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Ju H, Zhang J, Zou Y, Xie F, Tang X, Zhang S, Li J. Bacteria undergo significant shifts while archaea maintain stability in Pocillopora damicornis under sustained heat stress. Environ Res 2024; 250:118469. [PMID: 38354884 DOI: 10.1016/j.envres.2024.118469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 02/05/2024] [Accepted: 02/10/2024] [Indexed: 02/16/2024]
Abstract
Global warming reportedly poses a critical risk to coral reef ecosystems. Bacteria and archaea are crucial components of the coral holobiont. The response of archaea associated with warming is less well understood than that of the bacterial community in corals. Also, there have been few studies on the dynamics of the microbial community in the coral holobiont under long-term heat stress. In order to track the dynamic alternations in the microbial communities within the heat-stressed coral holobiont, three-week heat-stress monitoring was carried out on the coral Pocillopora damicornis. The findings demonstrate that the corals were stressed at 32 °C, and showed a gradual decrease in Symbiodiniaceae density with increasing duration of heat stress. The archaeal community in the coral holobiont remained relatively unaltered by the increasing temperature, whereas the bacterial community was considerably altered. Sustained heat stress exacerbated the dissimilarities among parallel samples of the bacterial community, confirming the Anna Karenina Principle in animal microbiomes. Heat stress leads to more complex and unstable microbial networks, characterized by an increased average degree and decreased modularity, respectively. With the extension of heat stress duration, the relative abundances of the gene (nifH) and genus (Tistlia) associated with nitrogen fixation increased in coral samples, as well as the potential pathogenic bacteria (Flavobacteriales) and opportunistic bacteria (Bacteroides). Hence, our findings suggest that coral hosts might recruit nitrogen-fixing bacteria during the initial stages of suffering heat stress. An environment that is conducive to the colonization and development of opportunistic and pathogenic bacteria when the coral host becomes more susceptible as heat stress duration increases.
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Affiliation(s)
- Huimin Ju
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jian Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; Sanya National Marine Ecosystem Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Yiyang Zou
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Feiyang Xie
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Xiaoyu Tang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Si Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; Sanya National Marine Ecosystem Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China
| | - Jie Li
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; Sanya National Marine Ecosystem Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China.
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Yuan Y, Chen Z, Huang X, Wang F, Guo H, Huang Z, Yang H. Comparative analysis of nitrogen content and its influence on actinorhizal nodule and rhizospheric microorganism diversity in three Alnus species. Front Microbiol 2023; 14:1230170. [PMID: 38169791 PMCID: PMC10758417 DOI: 10.3389/fmicb.2023.1230170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 11/24/2023] [Indexed: 01/05/2024] Open
Abstract
Alnus spp. (alder) are typical nonleguminous nitrogen-fixing trees that have a symbiotic relationship with Frankia. To explore the differences in nitrogen-fixing microorganisms between three alders (A. cremastogyne, A. glutinosa, and A. formosana) with different chromosome ploidies, the community structure and compositional diversity of potential nitrogen-fixing microorganism in root nodules and rhizosphere soil were comparatively analyzed using 16S rRNA and nitrogenase (nifH) gene sequencing. The nitrogen contents in the root nodules and rhizosphere soil were also determined. The results showed that the contents of total nitrogen and nitrate nitrogen in the root nodules of the three alders are significantly higher than those in the rhizosphere soils, while the ammonium nitrogen content show the opposite trend. The family, genus, and species levels showed obviously differences between root nodules and rhizosphere soils, while there were no significant differences at the classification level between the three alders. At the phylum level, the dominant phyla from 16S rRNA and nifH gene data in the root nodules and rhizosphere soil of the three alders are phylum Actinomycetota and phylum Pseudomonadota, respectively. The LEfSe results showed that there are significant differences in the dominant groups in the root nodules and rhizosphere oil of the three alders. The relative abundances of dominant groups also showed obvious differences between the root nodules and rhizosphere soils of three alders. The relative abundances of Frankia and unclassified_Frankia in root nodules are obviously higher than those in rhizosphere soils, and their relative abundances in A. glutinosa root nodules are significantly higher than those in A. cremastogyne and A. formosana at the genus and species levels. The diversity of potential nitrogen-fixing microorganism from 16S rRNA and nifH gene data in the A. glutinosa root nodules and rhizosphere soils are all higher than those in A. cremastogyne and A. formosana. The results of functional prediction also showed that the OTUs for nitrogen fixation, nitrate respiration, and ureolysis in A. glutinosa root nodules are higher than those in the other two alders. Redundancy analysis revealed that the total nitrogen content mostly affects the Frankia community. Overall, there are significant differences in the community composition and structure of potential nitrogen-fixing microorganism in the root nodules and rhizosphere soils between the three alders. A. glutinosa showed a relatively stronger nitrogen fixation capacity than A. formosana and A. cremastogyne. The results help elucidates how the community structure and nitrogen-fixing ability of potential nitrogen-fixing microorganism differ between alder species and serve as a reference for applying Frankia to alder plantations.
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Affiliation(s)
- Yuwei Yuan
- Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, National Forestry and Grassland Administration Key Laboratory of Forest Resource Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, Rainy Area of West China Plantation Ecosystem Permanent Scientific Research Base, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Zhi Chen
- Sichuan Key Laboratory of Ecological Restoration and Conservation for Forest and Wetland, Sichuan Academy of Forestry, Chengdu, China
| | - Xin Huang
- Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, National Forestry and Grassland Administration Key Laboratory of Forest Resource Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, Rainy Area of West China Plantation Ecosystem Permanent Scientific Research Base, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Fang Wang
- Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, National Forestry and Grassland Administration Key Laboratory of Forest Resource Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, Rainy Area of West China Plantation Ecosystem Permanent Scientific Research Base, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Hongying Guo
- Sichuan Academy of Grassland Sciences, Chengdu, China
| | - Zhen Huang
- Sichuan Key Laboratory of Ecological Restoration and Conservation for Forest and Wetland, Sichuan Academy of Forestry, Chengdu, China
| | - Hanbo Yang
- Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, National Forestry and Grassland Administration Key Laboratory of Forest Resource Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, Rainy Area of West China Plantation Ecosystem Permanent Scientific Research Base, College of Forestry, Sichuan Agricultural University, Chengdu, China
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Zhu YG, Peng J, Chen C, Xiong C, Li S, Ge A, Wang E, Liesack W. Harnessing biological nitrogen fixation in plant leaves. Trends Plant Sci 2023; 28:1391-1405. [PMID: 37270352 DOI: 10.1016/j.tplants.2023.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 06/05/2023]
Abstract
The importance of biological nitrogen fixation (BNF) in securing food production for the growing world population with minimal environmental cost has been increasingly acknowledged. Leaf surfaces are one of the biggest microbial habitats on Earth, harboring diverse free-living N2-fixers. These microbes inhabit the epiphytic and endophytic phyllosphere and contribute significantly to plant N supply and growth. Here, we summarize the contribution of phyllosphere-BNF to global N cycling, evaluate the diversity of leaf-associated N2-fixers across plant hosts and ecosystems, illustrate the ecological adaptation of N2-fixers to the phyllosphere, and identify the environmental factors driving BNF. Finally, we discuss potential BNF engineering strategies to improve the nitrogen uptake in plant leaves and thus sustainable food production.
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Affiliation(s)
- Yong-Guan Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
| | - Jingjing Peng
- State Key Laboratory of Nutrient Use and Management, College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, China Agricultural University, Beijing, 100193, China
| | - Cai Chen
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Chao Xiong
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Shule Li
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Anhui Ge
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, SIBS, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Ertao Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, SIBS, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Werner Liesack
- Max Planck Institute for Terrestrial Microbiology, Marburg, 35043, Germany
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Hu J, Wang J, Yang S, Qi S, Jiang Z, Dai H, Zhou J. Soil nitrogen functional transformation microbial genes response to biochar application in different irrigation paddy field in southern China. Environ Sci Pollut Res Int 2023; 30:7770-7785. [PMID: 36044151 DOI: 10.1007/s11356-022-22728-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
Growing evidence points to the controlled irrigation (CI) and biochar application (BA) having agricultural economic value and ecological benefits, but their synergistic effect and microbial mechanism of nitrogen conversion remain unknown in paddy fields. The effects of different BA (0, 20, 40 t/hm2) on the soil nitrogen functional transformation microbial genes (nifH, AOA-amoA, AOB-amoA) in different irrigation (CI, flooding irrigation) were clarified. After one seasonal growth of paddy, the correlation between the abundance of functional genes OUT and soil nitrogen transformation environment factors during the typical growth period was analyzed. High-throughput sequencing results illustrated that the application of CC (40 t/hm2 biochar) increased the nifH genes bacterial community abundance; the abundance of dominant microorganism increased by 79.68~86.19%. Because biochar can potentially control the rates of N cycling in soil systems by adsorbing ammonia and increasing NH4+ storage, it increased soil NH4+-N and NO3--N content by 60.77% and 26.14%, improving microbial nitrogen fixation. Rare species Nitrosopumilus, Nitrosococcus, and Methylocystis appeared in biochar treatments group, which increased the diversity of microbial in paddy. The combined use of CI and BA affected soil inorganic nitrogen content, temperature (T), pH, Eh, etc., which affected urease, urea hydrolysis, and nitrogen functional transformation microorganism genes. Correlation analysis shows that soil NH4+-N, T, and Eh, respectively, are significant factors for the formation of nifH, AOA-amoA, and AOB-amoA soil bacterial communities, respectively. This study suggests that to maintain the biodiversity of soil and realize the sustainable development of rice cultivation, CI is of great importance in combination with BA.
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Affiliation(s)
- Jiazhen Hu
- College of Agricultural Science and Engineering, Hohai University, 8th Focheng West Road, Jiangning District, Nanjing, 210098, China
| | - Jie Wang
- Development Center for Science and Technology of Rural Water Resources of Jiangsu Province, Nanjing, 210029, China
| | - Shihong Yang
- College of Agricultural Science and Engineering, Hohai University, 8th Focheng West Road, Jiangning District, Nanjing, 210098, China.
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, 210098, China.
| | - Suting Qi
- College of Agricultural Science and Engineering, Hohai University, 8th Focheng West Road, Jiangning District, Nanjing, 210098, China
| | - Zewei Jiang
- College of Agricultural Science and Engineering, Hohai University, 8th Focheng West Road, Jiangning District, Nanjing, 210098, China
| | - Huidong Dai
- Urban Water Scheduling and Information Management Department of Kunshan City, Kunshan, 215300, China
| | - Jiaoyan Zhou
- Urban Water Scheduling and Information Management Department of Kunshan City, Kunshan, 215300, China
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Ai J, Yu T, Liu X, Jiang Y, Hao Z, Zhao X, Wang E, Deng Z. Nodule-associated diazotrophic community succession is driven by developmental phases combined with microhabitat of Sophora davidii. Front Microbiol 2022; 13:1078208. [PMID: 36532429 PMCID: PMC9751200 DOI: 10.3389/fmicb.2022.1078208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022] Open
Abstract
Nodule-associated nitrogen-fixing microorganisms (diazotrophs) residing in legume root nodules, and they have the potential to enhance legume survival. However, the succession characteristics and mechanisms of leguminous diazotrophic communities remain largely unexplored. We performed a high-throughput nifH amplicon sequencing with samples of root nodules and soil in the three developmental phases (young nodules, active nodules and senescent nodules) of the Sophora davidii (Franch.) Skeels root nodules, aiming to investigate the dynamics of nodule-endophytic diazotrophs during three developmental phases of root nodules. The results demonstrated the presence of diverse diazotrophic bacteria and successional community shifting dominated by Mesorhizobium and Bradyrhizobium inside the nodule according to the nodule development. The relative abundance decreased for Mesorhizobium, while decreased first and then increased for Bradyrhizobium in nodule development from young to active to senescent. Additionally, strains M. amorphae BT-30 and B. diazoefficiens B-26 were isolated and selected to test the interaction between them in co-cultured conditions. Under co-culture conditions: B. diazoefficiens B-26 significantly inhibited the growth of M. amorphae BT-30. Intriguingly, growth of B. diazoefficiens B-26 was significantly promoted by co'culture with M. amorphae BT-30 and could utilize some carbon and nitrogen sources that M. amorphae BT-30 could not. Additionally, the composition of microbial community varied in root nodules, in rhizosphere and in bulk soil. Collectively, our study highlights that developmental phases of nodules and the host microhabitat were the key driving factors for the succession of nodule-associated diazotrophic community.
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Affiliation(s)
- Jiamin Ai
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Tianfei Yu
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Xiaodong Liu
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Yingying Jiang
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Ziwei Hao
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Xiaoyu Zhao
- College of Life Sciences, Yan’an University, Yan’an, China
| | - Entao Wang
- , Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Zhenshan Deng
- College of Life Sciences, Yan’an University, Yan’an, China,*Correspondence: Zhenshan Deng,
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Gradoville MR, Dugenne M, Hynes AM, Zehr JP, White AE. Empirical relationship between nifH gene abundance and diazotroph cell concentration in the North Pacific Subtropical Gyre. J Phycol 2022; 58:829-833. [PMID: 36266252 DOI: 10.1111/jpy.13289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Cyanobacterial N2 -fixing microorganisms (diazotrophs) play a critical role in nitrogen and carbon cycling in the oceans; hence, accurate measurements of diazotroph abundance are imperative for understanding ocean biogeochemistry. Marine diazotroph abundances are often assessed using qPCR of the nifH gene, a sensitive, taxa-specific, and time/cost-efficient method. However, the validity of nifH abundance as a proxy for cell concentration has recently been questioned. Here, we compare nifH gene abundances to cell counts for four diazotroph taxa (Trichodesmium, Crocosphaera, Richelia, and Calothrix) on two cruises to the North Pacific Subtropical Gyre, one of the largest habitats for marine diazotrophs. nifH:cell relationships were strong and significant for Crocosphaera, Richelia, and Calothrix (nifH:cell 1.51-2.58; R2 = 0.89-0.96) but were not significant for Trichodesmium, despite previous studies reporting significant nifH:cell relationships for this organism. Limited available data suggest that empirical nifH:cell can vary among studies but that relationships are usually significantly linear and >1:1. Our study indicates that nifH gene abundance, while not a direct measure of cells, is a useful quantitative proxy for diazotroph abundance.
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Affiliation(s)
- Mary R Gradoville
- Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, California, 95064, USA
| | - Mathilde Dugenne
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, Hawaii, 96822, USA
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawai'i at Mānoa, Honolulu, Hawaii, 96822, USA
| | - Annette M Hynes
- School of Oceanography, University of Washington, Seattle, Washington, 98195, USA
| | - Jonathan P Zehr
- Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, California, 95064, USA
| | - Angelicque E White
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, Hawaii, 96822, USA
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawai'i at Mānoa, Honolulu, Hawaii, 96822, USA
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Rui J, Hu J, Wang F, Zhao Y, Li C. Altitudinal niches of symbiotic, associative and free-living diazotrophs driven by soil moisture and temperature in the alpine meadow on the Tibetan Plateau. Environ Res 2022; 211:113033. [PMID: 35276191 DOI: 10.1016/j.envres.2022.113033] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Legume-associated symbiotic diazotrophs contribute more to nitrogen (N) fixation than non-symbiotic diazotrophs in many terrestrial ecosystems. However, the percentage of legume biomass is low in alpine meadows on the Tibetan Plateau. Therefore, non-symbiotic diazotrophs may play important roles in N fixation in alpine meadow soils. Moreover, Tibetan alpine meadows are fragile and sensitive to global climate change, and the investigating of the key factor driving soil diazotrophic community still entails several challenges. To address these issues, we investigated diazotrophic spatial distribution and diversity along the elevational gradient between 3200 and 4200 m in the alpine meadow using amplicon sequencing of nifH gene. The result clearly showed that soil moisture and temperature were key factors driving soil diazotrophic community structures. Both altitude and soil depth significantly differentiated diazotrophic community composition. Alpha diversity indices of diazotrophic communities showed unimodal distribution along elevation gradient, strongly affected by soil moisture. Altitudinal niches were occupied by different diazotrophs. Soils at lower elevations were dominated by symbiotic diazotrophs and associative diazotrophs related to high biomass of plant hosts, while those at higher elevations were dominated by free-living psychrophiles such as Polaromonas. Furthermore, high moisture stimulated free-living anaerobes at middle elevations, such as Geobacter and Anaeromyxobacter, while suppressed legumes and symbiotic Mezorhizobium. Soil temperature not only directly affected temperature-sensitive diazotrophs, but also indirectly affected them through plants and soil properties such as pH and ammonium content. Our results suggest that climate change may strongly affect biological nitrogen fixation (BNF), and free-living diazotrophs may play important roles in BNF of alpine meadow system on the Tibetan Plateau.
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Affiliation(s)
- Junpeng Rui
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China; Center for Grassland Microbiome, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China.
| | - Jingjing Hu
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Fuxin Wang
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Yuwei Zhao
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Chao Li
- State Key Laboratory of Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
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Abstract
BACKGROUND The importance of symbiosis has long been recognized on coral reefs, where the photosynthetic dinoflagellates of corals (Symbiodiniaceae) are the primary symbiont. Numerous studies have now shown that a diverse assemblage of prokaryotes also make-up part of the microbiome of corals. A subset of these prokaryotes is capable of fixing nitrogen, known as diazotrophs, and is also present in the microbiome of scleractinian corals where they have been shown to supplement the holobiont nitrogen budget. Here, an analysis of the microbiomes of 16 coral species collected from Australia, Curaçao, and Hawai'i using three different marker genes (16S rRNA, nifH, and ITS2) is presented. These data were used to examine the effects of biogeography, coral traits, and ecological life history characteristics on the composition and diversity of the microbiome in corals and their diazotrophic communities. RESULTS The prokaryotic microbiome community composition (i.e., beta diversity) based on the 16S rRNA gene varied between sites and ecological life history characteristics, but coral morphology was the most significant factor affecting the microbiome of the corals studied. For 15 of the corals studied, only two species Pocillopora acuta and Seriotopora hystrix, both brooders, showed a weak relationship between the 16S rRNA gene community structure and the diazotrophic members of the microbiome using the nifH marker gene, suggesting that many corals support a microbiome with diazotrophic capabilities. The order Rhizobiales, a taxon that contains primarily diazotrophs, are common members of the coral microbiome and were eight times greater in relative abundances in Hawai'i compared to corals from either Curacao or Australia. However, for the diazotrophic component of the coral microbiome, only host species significantly influenced the composition and diversity of the community. CONCLUSIONS The roles and interactions between members of the coral holobiont are still not well understood, especially critical functions provided by the coral microbiome (e.g., nitrogen fixation), and the variation of these functions across species. The findings presented here show the significant effect of morphology, a coral "super trait," on the overall community structure of the microbiome in corals and that there is a strong association of the diazotrophic community within the microbiome of corals. However, the underlying coral traits linking the effects of host species on diazotrophic communities remain unknown. Video Abstract.
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Affiliation(s)
- Kathleen M Morrow
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
- Present address: Thomas Jefferson High School for Science and Technology, 6560 Braddock Rd, Alexandria, VA, 22312, USA
| | - M Sabrina Pankey
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Michael P Lesser
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA.
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Kim N, Riggins CW, Zabaloy MC, Rodriguez-Zas SL, Villamil MB. Limited Impacts of Cover Cropping on Soil N-Cycling Microbial Communities of Long-Term Corn Monocultures. Front Microbiol 2022; 13:926592. [PMID: 35755999 PMCID: PMC9226624 DOI: 10.3389/fmicb.2022.926592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/11/2022] [Indexed: 11/17/2022] Open
Abstract
Cover cropping (CC) is a promising in-field practice to mitigate soil health degradation and nitrogen (N) losses from excessive N fertilization. Soil N-cycling microbial communities are the fundamental drivers of these processes, but how they respond to CC under field conditions is poorly documented for typical agricultural systems. Our objective was to investigate this relationship for a long-term (36 years) corn [Zea mays L.] monocultures under three N fertilizer rates (N0, N202, and N269; kg N/ha), where a mixture of cereal rye [Secale cereale L.] and hairy vetch [Vicia villosa Roth.] was introduced for two consecutive years, using winter fallows as controls (BF). A 3 × 2 split-plot arrangement of N rates and CC treatments in a randomized complete block design with three replications was deployed. Soil chemical and physical properties and potential nitrification (PNR) and denitrification (PDR) rates were measured along with functional genes, including nifH, archaeal and bacterial amoA, nirK, nirS, and nosZ-I, sequenced in Illumina MiSeq system and quantified in high-throughput quantitative polymerase chain reaction (qPCR). The abundances of nifH, archaeal amoA, and nirS decreased with N fertilization (by 7.9, 4.8, and 38.9 times, respectively), and correlated positively with soil pH. Bacterial amoA increased by 2.4 times with CC within N269 and correlated positively with soil nitrate. CC increased the abundance of nirK by 1.5 times when fertilized. For both bacterial amoA and nirK, N202 and N269 did not differ from N0 within BF. Treatments had no significant effects on nosZ-I. The reported changes did not translate into differences in functionality as PNR and PDR did not respond to treatments. These results suggested that N fertilization disrupts the soil N-cycling communities of this system primarily through soil acidification and high nutrient availability. Two years of CC may not be enough to change the N-cycling communities that adapted to decades of disruption from N fertilization in corn monoculture. This is valuable primary information to understand the potentials and limitations of CC when introduced into long-term agricultural systems.
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Affiliation(s)
- Nakian Kim
- Department of Crop Sciences, University of Illinois, Urbana, IL, United States
| | - Chance W. Riggins
- Department of Crop Sciences, University of Illinois, Urbana, IL, United States
| | - María C. Zabaloy
- Centro de Recursos Naturales Renovables de la Zona Semiárida, UNS-CONICET, Departamento de Agronomía, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | | | - María B. Villamil
- Department of Crop Sciences, University of Illinois, Urbana, IL, United States
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Malviya MK, Li CN, Lakshmanan P, Solanki MK, Wang Z, Solanki AC, Nong Q, Verma KK, Singh RK, Singh P, Sharma A, Guo DJ, Dessoky ES, Song XP, Li YR. High-Throughput Sequencing-Based Analysis of Rhizosphere and Diazotrophic Bacterial Diversity Among Wild Progenitor and Closely Related Species of Sugarcane ( Saccharum spp. Inter-Specific Hybrids). Front Plant Sci 2022; 13:829337. [PMID: 35283913 PMCID: PMC8908384 DOI: 10.3389/fpls.2022.829337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/04/2022] [Indexed: 05/14/2023]
Abstract
Considering the significant role of genetic background in plant-microbe interactions and that most crop rhizospheric microbial research was focused on cultivars, understanding the diversity of root-associated microbiomes in wild progenitors and closely related crossable species may help to breed better cultivars. This study is aimed to fill a critical knowledge gap on rhizosphere and diazotroph bacterial diversity in the wild progenitors of sugarcane, the essential sugar and the second largest bioenergy crop globally. Using a high-throughput sequencing (HTS) platform, we studied the rhizosphere and diazotroph bacterial community of Saccharum officinarum L. cv. Badila (BRS), Saccharum barberi (S. barberi) Jesw. cv Pansahi (PRS), Saccharum robustum [S. robustum; (RRS), Saccharum spontaneum (S. spontaneum); SRS], and Saccharum sinense (S. sinense) Roxb. cv Uba (URS) by sequencing their 16S rRNA and nifH genes. HTS results revealed that a total of 6,202 bacteria-specific operational taxonomic units (OTUs) were identified, that were distributed as 107 bacterial groups. Out of that, 31 rhizobacterial families are commonly spread in all five species. With respect to nifH gene, S. barberi and S. spontaneum recorded the highest and lowest number of OTUs, respectively. These results were validated by quantitative PCR analysis of both genes. A total of 1,099 OTUs were identified for diazotrophs with a core microbiome of 9 families distributed among all the sugarcane species. The core microbiomes were spread across 20 genera. The increased microbial diversity in the rhizosphere was mainly due to soil physiochemical properties. Most of the genera of rhizobacteria and diazotrophs showed a positive correlation, and few genera negatively correlated with the soil properties. The results showed that sizeable rhizospheric diversity exists across progenitors and close relatives. Still, incidentally, the rhizosphere microbial abundance of progenitors of modern sugarcane was at the lower end of the spectrum, indicating the prospect of Saccharum species introgression breeding may further improve nutrient use and disease and stress tolerance of commercial sugarcane. The considerable variation for rhizosphere microbiome seen in Saccharum species also provides a knowledge base and an experimental system for studying the evolution of rhizobacteria-host plant association during crop domestication.
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Affiliation(s)
- Mukesh Kumar Malviya
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Chang-Ning Li
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Prakash Lakshmanan
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, China
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, St. Lucia, QLD, Australia
| | - Manoj Kumar Solanki
- Plant Cytogenetics and Molecular Biology Group, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Zhen Wang
- Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology, College of Biology and Pharmacy, Yulin Normal University, Yulin, China
| | | | - Qian Nong
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Krishan K. Verma
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Rajesh Kumar Singh
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Pratiksha Singh
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Anjney Sharma
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Dao-Jun Guo
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
- College of Agriculture, Guangxi University, Nanning, China
| | | | - Xiu-Peng Song
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
- *Correspondence: Xiu-Peng Song
| | - Yang-Rui Li
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
- College of Agriculture, Guangxi University, Nanning, China
- Yang-Rui Li ; orcid.org/0000-0002-7559-9244
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11
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Etto RM, Jesus EDC, Cruz LM, Schneider BSF, Tomachewski D, Urrea-Valencia S, Gonçalves DRP, Galvão F, Ayub RA, Curcio GR, Steffens MBR, Galvão CW. Influence of environmental factors on the tropical peatlands diazotrophic communities from the Southern Brazilian Atlantic Rain Forest. Lett Appl Microbiol 2021; 74:543-554. [PMID: 34951701 DOI: 10.1111/lam.13638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 10/10/2021] [Accepted: 12/17/2021] [Indexed: 11/26/2022]
Abstract
The tropical peatlands of southern Brazil are essential for the maintenance of the Atlantic Rain Forest, one of the 25 hotspots of biodiversity in the world. Although diazotrophic microorganisms are essential for the maintenance of this nitrogen limited ecosystem, so far studies have focused only on microorganisms involved in the carbon cycle. In this work, peat samples were collected from three tropical peatland regions during dry and rainy seasons and their chemical and microbial characteristics were evaluated. Our results showed that the structure of the diazotrophic communities in the Brazilian tropical peatlands differs in the evaluated seasons. The abundance of the genus Bradyrhizobium showed to be affected by rainfall and peat pH. Despite the shifts of the nitrogen fixing population in the tropical peatland caused by seasonality it showed to be constantly dominated by α-Proteobacteria followed by Cyanobacteria. In addition, more than 50% of nifH gene sequences have not been classified, indicating the necessity for more studies in tropical peatland, since the reduction of N supply in the peatlands stimulates the recalcitrant organic matter decomposition performed by peatland microorganisms, influencing the C stock.
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Affiliation(s)
- Rafael Mazer Etto
- Microbial Molecular Biology Laboratory, State University of Ponta Grossa, CEP, 84030-900, Ponta Grossa - PR, Brazil
| | | | - Leonardo Magalhães Cruz
- Nucleus of Nitrogen Fixation, Federal University of Paraná, CEP, 81531-980, Curitiba - PR, Brazil
| | | | - Douglas Tomachewski
- Microbial Molecular Biology Laboratory, State University of Ponta Grossa, CEP, 84030-900, Ponta Grossa - PR, Brazil
| | - Salomé Urrea-Valencia
- Microbial Molecular Biology Laboratory, State University of Ponta Grossa, CEP, 84030-900, Ponta Grossa - PR, Brazil
| | - Daniel Ruiz Potma Gonçalves
- Microbial Molecular Biology Laboratory, State University of Ponta Grossa, CEP, 84030-900, Ponta Grossa - PR, Brazil
| | - Franklin Galvão
- Forest Ecology Laboratory, Universidade Federal do Paraná, CEP, 80210-170, Curitiba - PR, Brazil
| | - Ricardo Antônio Ayub
- Applied Biotechnology Laboratory, State University of Ponta Grossa, CEP, 84030-900, Ponta Grossa - PR, Brazil
| | | | | | - Carolina Weigert Galvão
- Microbial Molecular Biology Laboratory, State University of Ponta Grossa, CEP, 84030-900, Ponta Grossa - PR, Brazil
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12
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Yamada S, Suzuki Y, Kouzuma A, Watanabe K. Development of a CRISPR interference system for selective gene knockdown in Acidithiobacillus ferrooxidans. J Biosci Bioeng 2021; 133:105-109. [PMID: 34865958 DOI: 10.1016/j.jbiosc.2021.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/18/2021] [Accepted: 10/29/2021] [Indexed: 11/26/2022]
Abstract
Acidithiobacillus ferrooxidans is an iron-oxidizing chemolithotroph used for bioleaching of precious metals and is also regarded as a potential host for bioelectrochemical production of value-added chemicals. Despite its industrial utility, however, it is difficult to genetically engineer A. ferrooxidans due to low transformation and recombination efficiencies. Here, we developed a clustered regularly interspaced short palindromic repeats interference (CRISPRi) system that can selectively repress the expression of a target gene in A. ferrooxidans. The mutated gene encoding a nuclease-deactivated Cas9 protein was cloned into the broad-host-range plasmid pBBR1-MCS2, and the applicability of the CRISPRi system was examined using the nitrogenase nifH gene as a knockdown target. Introduction of the CRISPRi plasmid into A. ferrooxidans resulted in decreased nifH transcription and retarded cell growth in the absence of nitrogen sources, demonstrating that the CRISPRi system altered the phenotype of this bacterium via selective gene knockdown. We suggest that the CRISPRi system developed in this study provides an efficient technique for constructing A. ferrooxidans knockdown mutants that are useful for the genetic dissection of this bacterium.
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Affiliation(s)
- Shohei Yamada
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Yusuke Suzuki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
| | - Kazuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
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13
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Zani RDOA, Ferro M, Bacci M. Three phylogenetically distinct and culturable diazotrophs are perennial symbionts of leaf-cutting ants. Ecol Evol 2021; 11:17686-17699. [PMID: 35003632 PMCID: PMC8717316 DOI: 10.1002/ece3.8213] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 09/06/2021] [Accepted: 09/21/2021] [Indexed: 02/04/2023] Open
Abstract
The obligate mutualistic basidiomycete fungus, Leucocoprinus gongylophorus, mediates nutrition of leaf-cutting ants with carbons from vegetal matter. In addition, diazotrophic Enterobacteriales in the fungus garden and intestinal Rhizobiales supposedly mediate assimilation of atmospheric nitrogen, and Entomoplasmatales in the genus Mesoplasma, as well as other yet unidentified strains, supposedly mediate ant assimilation of other compounds from vegetal matter, such as citrate, fructose, and amino acids. Together, these nutritional partners would support the production of high yields of leafcutter biomass. In the present investigation, we propose that three phylogenetically distinct and culturable diazotrophs in the genera Ralstonia, Methylobacterium, and Pseudomonas integrate this symbiotic nutrition network, facilitating ant nutrition on nitrogen. Strains in these genera were often isolated and directly sequenced in 16S rRNA libraries from the ant abdomen, together with the nondiazotrophs Acinetobacter and Brachybacterium. These five isolates were underrepresented in libraries, suggesting that none of them is dominant in vivo. Libraries have been dominated by four uncultured Rhizobiales strains in the genera Liberibacter, Terasakiella, and Bartonella and, only in Acromyrmex ants, by the Entomoplasmatales in the genus Mesoplasma. Acromyrmex also presented small amounts of two other uncultured Entomoplasmatales strains, Entomoplasma and Spiroplasma. The absence of Entomoplasmatales in Atta workers implicates that the association with these bacteria is not mandatory for ant biomass production. Most of the strains that we detected in South American ants were genetically similar with strains previously described in association with leafcutters from Central and North America, indicating wide geographic dispersion, and suggesting fixed ecological services.
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Affiliation(s)
| | - Milene Ferro
- Centro de Estudos de Insetos Sociais (CEIS)Universidade Estadual Paulista (UNESP)Rio Claro ‐ SPBrazil
| | - Maurício Bacci
- Centro de Estudos de Insetos Sociais (CEIS)Universidade Estadual Paulista (UNESP)Rio Claro ‐ SPBrazil
- Departamento de Biologia Geral e AplicadaUniversidade Estadual Paulista (UNESP)Rio Claro ‐ SPBrazil
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14
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Li L, Wu C, Huang D, Ding C, Wei Y, Sun J. Integrating Stochastic and Deterministic Process in the Biogeography of N 2-Fixing Cyanobacterium Candidatus Atelocyanobacterium Thalassa. Front Microbiol 2021; 12:654646. [PMID: 34745020 PMCID: PMC8566894 DOI: 10.3389/fmicb.2021.654646] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 09/22/2021] [Indexed: 11/13/2022] Open
Abstract
UCYN-A is one of the most widespread and important marine diazotrophs. Its unusual distribution in both cold/warm and coastal/oceanic waters challenges current understanding about what drives the biogeography of diazotrophs. This study assessed the community assembly processes of the nitrogen-fixing cyanobacterium UCYN-A, developing a framework of assembly processes underpinning the microbial biogeography and diversity. High-throughput sequencing and a qPCR approach targeting the nifH gene were used to investigate three tropical seas: the Bay of Bengal, the Western Pacific Ocean, and the South China Sea. Based on the neutral community model and two types of null models calculating the β-nearest taxon index and the normalized stochasticity ratio, we found that stochastic assembly processes could explain 66-92% of the community assembly; thus, they exert overwhelming influence on UCYN-A biogeography and diversity. Among the deterministic processes, temperature and coastal/oceanic position appeared to be the principal environmental factors driving UCYN-A diversity. In addition, a close linkage between assembly processes and UCYN-A abundance/diversity/drivers can provide clues for the unusual global distribution of UCYN-A.
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Affiliation(s)
- Liuyang Li
- College of Marine Science and Technology, China University of Geosciences, Wuhan, China.,State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chao Wu
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China
| | - Danyue Huang
- College of Marine Science and Technology, China University of Geosciences, Wuhan, China.,School of Oceanography, Shanghai Jiao Tong University, Shanghai, China
| | - Changling Ding
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China.,College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Yuqiu Wei
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Jun Sun
- College of Marine Science and Technology, China University of Geosciences, Wuhan, China
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15
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Wang H, Li X, Li X, Li F, Su Z, Zhang H. Community Composition and Co-Occurrence Patterns of Diazotrophs along a Soil Profile in Paddy Fields of Three Soil Types in China. Microb Ecol 2021; 82:961-970. [PMID: 33660069 DOI: 10.1007/s00248-021-01716-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 02/07/2021] [Indexed: 06/12/2023]
Abstract
Diazotrophs play a key role in biological nitrogen (N2) fixation. However, we know little about the distribution of the diazotrophic community along the soil profile in paddy fields. Here, we used Illumina MiSeq sequencing, targeting the nitrogenase reductase (nifH) gene, to investigate changes with depth (0-100 cm) in the diazotrophic community in paddy soils of three regions (Changshu, Hailun, and Yingtan) in China. The results indicated that most diazotrophs belonged to the phylum Proteobacteria, accounting for 78.05% of the total number of sequences. The diazotrophic diversity was generally highest in the 10-20 cm layer, and then significantly decreased with soil depth. Principal coordinate analysis and PERMANOVA indicated that the diazotrophic community structure was significantly affected by region and soil depth. There were obvious differences in the composition of the diazotrophic community between the topsoil (0-40 cm) and the subsoil (40-100 cm). Anaeromyxobacter, Sideroxydans, Methylomonas, Nostoc, Methanocella, and Methanosaeta were enriched in the topsoil, while Geobacter, Azoarcus, Bradyrhizobium, and Dechloromonas were concentrated in the subsoil. Furthermore, co-occurrence network analysis showed that the diazotrophic network in the topsoil was more complex than that in the subsoil. Distance-based redundancy analysis indicated that soil total C and N content and pH were the main factors influencing the vertical variation in the diazotrophic community. These results highlighted that depth has a great impact on the diazotrophic diversity, community composition, and co-occurrence patterns in paddy soil.
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Affiliation(s)
- Huanhuan Wang
- Shandong Provincial Key Laboratory of Energy Genetics, Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Xu Li
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
| | - Xinyu Li
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China.
| | - Fuli Li
- Shandong Provincial Key Laboratory of Energy Genetics, Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Zhencheng Su
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
| | - Huiwen Zhang
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
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16
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Koirala A, Brözel VS. Phylogeny of Nitrogenase Structural and Assembly Components Reveals New Insights into the Origin and Distribution of Nitrogen Fixation across Bacteria and Archaea. Microorganisms 2021; 9:microorganisms9081662. [PMID: 34442741 PMCID: PMC8399215 DOI: 10.3390/microorganisms9081662] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/16/2021] [Accepted: 07/30/2021] [Indexed: 11/16/2022] Open
Abstract
The phylogeny of nitrogenase has only been analyzed using the structural proteins NifHDK. As nifHDKENB has been established as the minimum number of genes necessary for in silico prediction of diazotrophy, we present an updated phylogeny of diazotrophs using both structural (NifHDK) and cofactor assembly proteins (NifENB). Annotated Nif sequences were obtained from InterPro from 963 culture-derived genomes. Nif sequences were aligned individually and concatenated to form one NifHDKENB sequence. Phylogenies obtained using PhyML, FastTree, RapidNJ, and ASTRAL from individuals and concatenated protein sequences were compared and analyzed. All six genes were found across the Actinobacteria, Aquificae, Bacteroidetes, Chlorobi, Chloroflexi, Cyanobacteria, Deferribacteres, Firmicutes, Fusobacteria, Nitrospira, Proteobacteria, PVC group, and Spirochaetes, as well as the Euryarchaeota. The phylogenies of individual Nif proteins were very similar to the overall NifHDKENB phylogeny, indicating the assembly proteins have evolved together. Our higher resolution database upheld the three cluster phylogeny, but revealed undocumented horizontal gene transfers across phyla. Only 48% of the 325 genera containing all six nif genes are currently supported by biochemical evidence of diazotrophy. In addition, this work provides reference for any inter-phyla comparison of Nif sequences and a quality database of Nif proteins that can be used for identifying new Nif sequences.
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Affiliation(s)
- Amrit Koirala
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USA;
| | - Volker S. Brözel
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USA;
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0004, South Africa
- Correspondence: ; Tel.: +1-605-688-6144
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17
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Landa M, Turk-Kubo KA, Cornejo-Castillo FM, Henke BA, Zehr JP. Critical Role of Light in the Growth and Activity of the Marine N 2-Fixing UCYN-A Symbiosis. Front Microbiol 2021; 12:666739. [PMID: 34025621 PMCID: PMC8139342 DOI: 10.3389/fmicb.2021.666739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/08/2021] [Indexed: 11/27/2022] Open
Abstract
The unicellular N2-fixing cyanobacteria UCYN-A live in symbiosis with haptophytes in the Braarudosphaera bigelowii lineage. Maintaining N2-fixing symbioses between two unicellular partners requires tight coordination of multiple biological processes including cell growth and division and, in the case of the UCYN-A symbiosis, N2 fixation of the symbiont and photosynthesis of the host. In this system, it is thought that the host photosynthesis supports the high energetic cost of N2 fixation, and both processes occur during the light period. However, information on this coordination is very limited and difficult to obtain because the UCYN-A symbiosis has yet to be available in culture. Natural populations containing the UCYN-A2 symbiosis were manipulated to explore the effects of alterations of regular light and dark periods and inhibition of host photosynthesis on N2 fixation (single cell N2 fixation rates), nifH gene transcription, and UCYN-A2 cell division (fluorescent in situ hybridization and nifH gene abundances). The results showed that the light period is critical for maintenance of regular patterns of gene expression, N2 fixation and symbiont replication and cell division. This study suggests a crucial role for the host as a producer of fixed carbon, rather than light itself, in the regulation and implementation of these cellular processes in UCYN-A.
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Affiliation(s)
- Marine Landa
- Ocean Sciences Department, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Kendra A Turk-Kubo
- Ocean Sciences Department, University of California, Santa Cruz, Santa Cruz, CA, United States
| | | | - Britt A Henke
- Ocean Sciences Department, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Jonathan P Zehr
- Ocean Sciences Department, University of California, Santa Cruz, Santa Cruz, CA, United States
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18
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Smercina DN, Evans SE, Friesen ML, Tiemann LK. Impacts of nitrogen addition on switchgrass root-associated diazotrophic community structure and function. FEMS Microbiol Ecol 2021; 96:5920613. [PMID: 33038234 DOI: 10.1093/femsec/fiaa208] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 10/08/2020] [Indexed: 02/02/2023] Open
Abstract
Cellulosic bioenergy crops, like switchgrass (Panicum virgatum), have potential for growth on lands unsuitable for food production coupled with potential for climate mitigation. Sustainability of these systems lies in identifying conditions that promote high biomass yields on marginal lands under low-input agricultural practices. Associative nitrogen fixation (ANF) is a potentially important nitrogen (N) source for these crops, yet ANF contributions to plant N, especially under fertilizer N addition are unclear. In this study, we assess structure (nifH) and function (ANF) of switchgrass root-associated diazotrophic communities to long-term and short-term N additions using soil from three marginal land sites. ANF rates were variable and often unexpectedly high, sometimes 10× greater than reported in the literature, and did not respond in repeatable ways to long-term or short-term N. We found few impacts of N addition on root-associated diazotrophic community structure or membership. Instead, we found a very consistent root-associated diazotrophic community even though switchgrass seeds were germinated in soil from field sites with distinct diazotrophic communities. Ultimately, this work demonstrates that root-associated diazotrophic communities have the potential to contribute to switchgrass N demands, independent of N addition, and this may be driven by selection of the diazotrophic community by switchgrass roots.
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Affiliation(s)
- Darian N Smercina
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA
| | - Sarah E Evans
- W.K. Kellogg Biological Station, Department of Integrative Biology, Michigan State University, Hickory Corners, MI 49060, USA
| | - Maren L Friesen
- Department of Plant Pathology, Washington State University, Pullman, WA 99164, USA.,Department of Crop and Soil Sciences, Washington State University, Pullman, WA 99164, USA
| | - Lisa K Tiemann
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA
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19
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Chen H, Zheng C, Qiao Y, Du S, Li W, Zhang X, Zhao Z, Cao C, Zhang W. Long-term organic and inorganic fertilization alters the diazotrophic abundance, community structure, and co-occurrence patterns in a vertisol. Sci Total Environ 2021; 766:142441. [PMID: 33097271 DOI: 10.1016/j.scitotenv.2020.142441] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 09/10/2020] [Accepted: 09/12/2020] [Indexed: 06/11/2023]
Abstract
Diazotrophs play a critical role in converting air-inactive nitrogen to bio-available nitrogen. Assessing the influences of different fertilization regimes on diazotrophs is essential for a better understanding of their maintenance of soil fertility and agricultural sustainability. In this study, we targeted the nifH gene to investigate the effects of different long-term fertilization on the diazotrophic community in a vertisol, using real-time quantitative polymerase chain reaction (PCR) and MiSeq sequencing. Five fertilization regimes were tested: no fertilizer (CK), chemical nitrogen, phosphorus, and potassium fertilizer (NPK), organic fertilizer (O), chemical NPK plus organic fertilizer with an equivalent application rate of nitrogen (NPKO), and chemical NPK plus organic fertilizer with a high application rate of nitrogen (HNPKO). Our results showed that fertilization significantly affected the diazotrophic activity, abundance and composition. NPK tended to reduce the activity, abundance, operational taxonomic units (OTU)-richness and alpha-diversity of the diazotrophs, while O had the opposite effect. The effects of inorganic and organic fertilization on the diazotrophs depended on the N application rate, showing that the diazotrophic activity, abundance, and alpha-diversity in NPKO were higher than that of HNPKO. For the diazotrophic community structure, CK, O, and NPKO were grouped and separated from NPK and HNPKO. The diazotrophic community structure strongly correlated with the soil pH, electrical conductivity (EC), total carbon content (TC), and total nitrogen content (TN), among which pH was the major factor shaping the diazotrophic community structure. Different network patterns were observed between the long-term organic and non-organic fertilizers, suggesting that the organic amendment resulted in a more complicated diazotrophic community than the non-organic amendments. Rhizobium was the most important hub connecting members in the community. These results indicated that organic amendments are beneficial to diazotrophic activity, abundance, OTU richness, alpha-diversity, and the diazotrophic communities' potential interactions, which may enhance biological nitrogen fixation in vertisols.
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Affiliation(s)
- Huan Chen
- Crop Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China; Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Chengyan Zheng
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yuqiang Qiao
- Crop Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Shizhou Du
- Crop Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Wei Li
- Crop Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Xiangqian Zhang
- Crop Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Zhu Zhao
- Crop Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Chengfu Cao
- Crop Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China.
| | - Weijian Zhang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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20
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Jabir T, Vipindas PV, Jesmi Y, Divya PS, Adarsh BM, Nafeesathul Miziriya HS, Mohamed Hatha AA. Influence of environmental factors on benthic nitrogen fixation and role of sulfur reducing diazotrophs in a eutrophic tropical estuary. Mar Pollut Bull 2021; 165:112126. [PMID: 33667934 DOI: 10.1016/j.marpolbul.2021.112126] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 05/20/2023]
Abstract
Benthic nitrogen fixation in the tropical estuaries plays a major role in marine nitrogen cycle, its contribution to nitrogen budget and players behind process is not well understood. The present study was estimated the benthic nitrogen fixation rate in a tropical estuary (Cochin) and also evaluated the contribution of various diazotrophic bacterial communities. Nitrogen fixation was detected throughout year (0.1-1.11 nmol N g-1 h-1); higher activity was observed in post-monsoon. The nifH gene abundance was varied from 0.8 × 104 to 0.6 × 108 copies g-1dry sediment; highest was detected in post-monsoon. The Cluster I and Cluster III were the dominant diazotrophs. Sulfur reducing bacterial phylotypes (Deltaproteobacteria) contributed up to 2-72% of total nitrogen fixation. These bacteria may provide new nitrogen to these systems, counteracting nitrogen loss via denitrification and anammox. Overall, the study explained the importance of benthic nitrogen fixation and role of diazotrophs in a monsoon influenced tropical estuarine environments.
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Affiliation(s)
- T Jabir
- Department of Marine Biology, Microbiology, Biochemistry, School of Marine Sciences, Cochin University of Science and Technology (CUSAT), Kochi 682016, India; National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Headland Sada, Vasco-da-Gama, Goa 403 804, India.
| | - P V Vipindas
- Department of Marine Biology, Microbiology, Biochemistry, School of Marine Sciences, Cochin University of Science and Technology (CUSAT), Kochi 682016, India; National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Headland Sada, Vasco-da-Gama, Goa 403 804, India
| | - Y Jesmi
- Department of Marine Biology, Microbiology, Biochemistry, School of Marine Sciences, Cochin University of Science and Technology (CUSAT), Kochi 682016, India
| | - P S Divya
- Department of Marine Biology, Microbiology, Biochemistry, School of Marine Sciences, Cochin University of Science and Technology (CUSAT), Kochi 682016, India
| | - B M Adarsh
- Department of Marine Biology, Microbiology, Biochemistry, School of Marine Sciences, Cochin University of Science and Technology (CUSAT), Kochi 682016, India
| | - H S Nafeesathul Miziriya
- Department of Marine Biology, Microbiology, Biochemistry, School of Marine Sciences, Cochin University of Science and Technology (CUSAT), Kochi 682016, India
| | - A A Mohamed Hatha
- Department of Marine Biology, Microbiology, Biochemistry, School of Marine Sciences, Cochin University of Science and Technology (CUSAT), Kochi 682016, India; CUSAT-NCPOR Centre for Polar Sciences, Cochin University of Science and Technology (CUSAT), Kochi 682 016, India.
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21
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Gao H, Li S, Wu F. Impact of Intercropping on the Diazotrophic Community in the Soils of Continuous Cucumber Cropping Systems. Front Microbiol 2021; 12:630302. [PMID: 33868191 PMCID: PMC8044418 DOI: 10.3389/fmicb.2021.630302] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/08/2021] [Indexed: 11/19/2022] Open
Abstract
Diazotrophs are important soil components that help replenish biologically available nitrogen (N) in the soil and contribute to minimizing the use of inorganic N fertilizers in agricultural ecosystems. However, there is little understanding of how diazotrophs respond to intercropping and soil physicochemical properties in cucumber continuous cropping systems. In this study, using the nifH gene as a marker, we have examined the impacts of seven intercropping plants on diazotrophic community diversity and composition compared to a cucumber continuous cropping system during two cropping seasons. The results showed that intercropping increased the abundance of the nifH gene, which was negatively correlated with available phosphorous in the fall. Diazotrophic diversity and richness were higher in the rape-cucumber system than in the monoculture. Multivariate regression tree analysis revealed that the diversity of the diazotrophic communties was shaped mainly by soil moisture and available phosphorous. Skermanella were the dominant genera in all of the samples, which increased significantly in the mustard-cucumber system in the fall. There was no effect of intercropping on the structure of the diazotrophic community in this case. Non-metric multidimensional scaling analysis showed that cropping season had a greater effect than intercropping on the community structure of the diazotrophs. Overall, our results suggest that intercropping altered the abundance and diversity rather than the structure of the diazotrophic community, which may potentially affect the N fixation ability of continuous cropping systems.
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Affiliation(s)
- Huan Gao
- Department of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, China
| | - Sen Li
- Department of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, China
| | - Fengzhi Wu
- Department of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, China
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22
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Halim MA, Choo QC, Ghazali AHA, Wajidi MFF, Najimudin N. Transcriptional analysis of nitrogen fixation in Paenibacillus durus during growth in nitrogen-enriched medium. Lett Appl Microbiol 2021; 72:610-618. [PMID: 33525052 DOI: 10.1111/lam.13455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 11/25/2020] [Accepted: 01/21/2021] [Indexed: 11/28/2022]
Abstract
Paenibacillus durus strain ATCC 35681T is a Gram-positive diazotroph that displayed capability of fixing nitrogen even in the presence of nitrate or ammonium. However, the nitrogen fixation activity was detected only at day 1 of growth when cultured in liquid nitrogen-enriched medium. The transcripts of all the nifH homologues were present throughout the 9-day study. When grown in nitrogen-depleted medium, nitrogenase activities occurred from day 1 until day 6 and the nifH transcripts were also present during the course of the study albeit at different levels. In both studies, the absence of nitrogen fixation activity regardless of the presence of the nifH transcripts raised the possibility of a post-transcriptional or post-translational regulation of the system. A putative SigA box sequence was found upstream of the transcription start site of nifB1, the first gene in the major nitrogen fixation cluster. The upstream region of nifB2 showed a promoter recognizable by SigE, a sigma factor normally involved in sporulation.
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Affiliation(s)
- M A Halim
- School of Biological Sciences, Universiti Sains Malaysia, Gelugor, Malaysia.,Biotechnology Research Institute, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Q C Choo
- Department of Biological Sciences, Universiti Tunku Abdul Rahman, Kampar, Malaysia
| | - A H A Ghazali
- School of Biological Sciences, Universiti Sains Malaysia, Gelugor, Malaysia
| | - M F F Wajidi
- School of Distance Education, Universiti Sains Malaysia, Gelugor, Malaysia
| | - N Najimudin
- School of Biological Sciences, Universiti Sains Malaysia, Gelugor, Malaysia
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Jabir T, Vipindas PV, Krishnan KP, Mohamed Hatha AA. Abundance and diversity of diazotrophs in the surface sediments of Kongsfjorden, an Arctic fjord. World J Microbiol Biotechnol 2021; 37:41. [PMID: 33544264 DOI: 10.1007/s11274-020-02993-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 12/27/2020] [Indexed: 10/22/2022]
Abstract
Diazotrophy in the Arctic environment is poorly understood compared to tropical and subtropical regions. Hence in this study, we report the abundance and diversity of diazotrophs in Arctic fjord sediments and elucidate the role of environmental factors on the distribution of diazotrophs. The study was conducted during the boreal summer in the Kongsfjorden, an Arctic fjord situated in the western coast of Spitsbergen. The abundance of nifH gene was measured through quantitative real-time PCR and the diversity of diazotrophs was assessed by nifH targeted clone library and next generation sequence analysis. Results revealed that the abundance of nifH gene in the surface sediments ranged from 2.3 × 106 to 3.7 × 107 copies g- 1. The δ-proteobacterial diazotrophs (71% of total sequence) were the dominant class observed in this study. Major genera retrieved from the sequence analysis were Desulfovibrionaceae (25% of total sequence), Desulfuromonadaceae (18% of total sequence) and Desulfobacteriaceae (10% of total sequence); these are important diazotrophic iron and sulfur-reducing bacterial clade in the Kongsfjorden sediments. The abundance of nifH gene showed a significant positive correlation TOC/TN ratio (r2 = 0.96, p ≤ 0.05) and total organic carbon (p ≤ 0.05) content in the fjord sediments. The higher TOC/TN ratio (4.24-14.5) indicated low nitrogen content organic matter in the fjord sediments through glacier runoff, which enhances the abundance and diversity of nitrogen fixing microorganisms.
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Affiliation(s)
- T Jabir
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences (Government of India), Headland Sada, Vasco-da-Gama, Goa, 403 804, India
| | - P V Vipindas
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences (Government of India), Headland Sada, Vasco-da-Gama, Goa, 403 804, India
| | - K P Krishnan
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences (Government of India), Headland Sada, Vasco-da-Gama, Goa, 403 804, India. .,CUSAT-NCPOR Centre for Polar Sciences, Cochin University of Science and Technology (CUSAT), Kochi, 682 016, India.
| | - A A Mohamed Hatha
- Department of Marine Biology, Microbiology, Biochemistry, School of Marine Sciences, Cochin University of Science and Technology (CUSAT), Kochi, 682 016, India.,CUSAT-NCPOR Centre for Polar Sciences, Cochin University of Science and Technology (CUSAT), Kochi, 682 016, India
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24
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Marzocchi U, Bonaglia S, Zaiko A, Quero GM, Vybernaite-Lubiene I, Politi T, Samuiloviene A, Zilius M, Bartoli M, Cardini U. Zebra Mussel Holobionts Fix and Recycle Nitrogen in Lagoon Sediments. Front Microbiol 2021; 11:610269. [PMID: 33542710 PMCID: PMC7851879 DOI: 10.3389/fmicb.2020.610269] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/29/2020] [Indexed: 01/04/2023] Open
Abstract
Bivalves are ubiquitous filter-feeders able to alter ecosystems functions. Their impact on nitrogen (N) cycling is commonly related to their filter-feeding activity, biodeposition, and excretion. A so far understudied impact is linked to the metabolism of the associated microbiome that together with the host constitute the mussel's holobiont. Here we investigated how colonies of the invasive zebra mussel (Dreissena polymorpha) alter benthic N cycling in the shallow water sediment of the largest European lagoon (the Curonian Lagoon). A set of incubations was conducted to quantify the holobiont's impact and to quantitatively compare it with the indirect influence of the mussel on sedimentary N transformations. Zebra mussels primarily enhanced the recycling of N to the water column by releasing mineralized algal biomass in the form of ammonium and by stimulating dissimilatory nitrate reduction to ammonium (DNRA). Notably, however, not only denitrification and DNRA, but also dinitrogen (N2) fixation was measured in association with the holobiont. The diazotrophic community of the holobiont diverged substantially from that of the water column, suggesting a unique niche for N2 fixation associated with the mussels. At the densities reported in the lagoon, mussel-associated N2 fixation may account for a substantial (and so far, overlooked) source of bioavailable N. Our findings contribute to improve our understanding on the ecosystem-level impact of zebra mussel, and potentially, of its ability to adapt to and colonize oligotrophic environments.
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Affiliation(s)
- Ugo Marzocchi
- Integrative Marine Ecology Department, Stazione Zoologica Anton Dohrn, National Institute of Marine Biology, Ecology and Biotechnology, Naples, Italy
- Marine Research Institute, Klaipėda University, Klaipėda, Lithuania
- Center for Water Technology (WATEC), Department of Biology, Aarhus University, Aarhus, Denmark
| | - Stefano Bonaglia
- Marine Research Institute, Klaipėda University, Klaipėda, Lithuania
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- Nordcee, Department of Biology, University of Southern Denmark, Odense, Denmark
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Anastasija Zaiko
- Marine Research Institute, Klaipėda University, Klaipėda, Lithuania
- Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
- Institute of Marine Science, University of Auckland, Auckland, New Zealand
| | - Grazia M. Quero
- Integrative Marine Ecology Department, Stazione Zoologica Anton Dohrn, National Institute of Marine Biology, Ecology and Biotechnology, Naples, Italy
- Institute for Biological Resources and Marine Biotechnologies, National Research Council of Italy, Ancona, Italy
| | | | - Tobia Politi
- Marine Research Institute, Klaipėda University, Klaipėda, Lithuania
| | | | - Mindaugas Zilius
- Marine Research Institute, Klaipėda University, Klaipėda, Lithuania
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Marco Bartoli
- Marine Research Institute, Klaipėda University, Klaipėda, Lithuania
- Department of Chemistry, Life science and Environmental Sustainability, Parma University, Parma, Italy
| | - Ulisse Cardini
- Integrative Marine Ecology Department, Stazione Zoologica Anton Dohrn, National Institute of Marine Biology, Ecology and Biotechnology, Naples, Italy
- Marine Research Institute, Klaipėda University, Klaipėda, Lithuania
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25
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von Friesen LW, Riemann L. Nitrogen Fixation in a Changing Arctic Ocean: An Overlooked Source of Nitrogen? Front Microbiol 2021; 11:596426. [PMID: 33391213 PMCID: PMC7775723 DOI: 10.3389/fmicb.2020.596426] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 11/17/2020] [Indexed: 11/13/2022] Open
Abstract
The Arctic Ocean is the smallest ocean on Earth, yet estimated to play a substantial role as a global carbon sink. As climate change is rapidly changing fundamental components of the Arctic, it is of local and global importance to understand and predict consequences for its carbon dynamics. Primary production in the Arctic Ocean is often nitrogen-limited, and this is predicted to increase in some regions. It is therefore of critical interest that biological nitrogen fixation, a process where some bacteria and archaea termed diazotrophs convert nitrogen gas to bioavailable ammonia, has now been detected in the Arctic Ocean. Several studies report diverse and active diazotrophs on various temporal and spatial scales across the Arctic Ocean. Their ecology and biogeochemical impact remain poorly known, and nitrogen fixation is so far absent from models of primary production in the Arctic Ocean. The composition of the diazotroph community appears distinct from other oceans – challenging paradigms of function and regulation of nitrogen fixation. There is evidence of both symbiotic cyanobacterial nitrogen fixation and heterotrophic diazotrophy, but large regions are not yet sampled, and the sparse quantitative data hamper conclusive insights. Hence, it remains to be determined to what extent nitrogen fixation represents a hitherto overlooked source of new nitrogen to consider when predicting future productivity of the Arctic Ocean. Here, we discuss current knowledge on diazotroph distribution, composition, and activity in pelagic and sea ice-associated environments of the Arctic Ocean. Based on this, we identify gaps and outline pertinent research questions in the context of a climate change-influenced Arctic Ocean – with the aim of guiding and encouraging future research on nitrogen fixation in this region.
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Affiliation(s)
- Lisa W von Friesen
- Marine Biology Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Lasse Riemann
- Marine Biology Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
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26
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Okamoto T, Shinjo R, Nishihara A, Uesaka K, Tanaka A, Sugiura D, Kondo M. Genotypic Variation of Endophytic Nitrogen-Fixing Activity and Bacterial Flora in Rice Stem Based on Sugar Content. Front Plant Sci 2021; 12:719259. [PMID: 34447404 PMCID: PMC8383490 DOI: 10.3389/fpls.2021.719259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/09/2021] [Indexed: 05/14/2023]
Abstract
Enhancement of the nitrogen-fixing ability of endophytic bacteria in rice is expected to result in improved nitrogen use under low-nitrogen conditions. Endophytic nitrogen-fixing bacteria require a large amount of energy to fix atmospheric nitrogen. However, it is unknown which carbon source and bacteria would affect nitrogen-fixing activity in rice. Therefore, this study examined genotypic variations in the nitrogen-fixing ability of rice plant stem as affected by non-structural carbohydrates and endophytic bacterial flora in field-grown rice. In the field experiments, six varieties and 10 genotypes of rice were grown in 2017 and 2018 to compare the acetylene reduction activity (nitrogen-fixing activity) and non-structural carbohydrates (glucose, sucrose, and starch) concentration in their stems at the heading stage. For the bacterial flora analysis, two genes were amplified using a primer set of 16S rRNA and nitrogenase (NifH) gene-specific primers. Next, acetylene reduction activity was correlated with sugar concentration among genotypes in both years, suggesting that the levels of soluble sugars influenced stem nitrogen-fixing activity. Bacterial flora analysis also suggested the presence of common and genotype-specific bacterial flora in both 16S rRNA and nifH genes. Similarly, bacteria classified as rhizobia, such as Bradyrhizobium sp. (Alphaproteobacteria) and Paraburkholderia sp. (Betaproteobacteria), were highly abundant in all rice genotypes, suggesting that these bacteria make major contributions to the nitrogen fixation process in rice stems. Gammaproteobacteria were more abundant in CG14 as well, which showed the highest acetylene reduction activity and sugar concentration among genotypes and is also proposed to contribute to the higher amount of nitrogen-fixing activity.
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Affiliation(s)
- Takanori Okamoto
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- *Correspondence: Takanori Okamoto
| | - Rina Shinjo
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Arisa Nishihara
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Kazuma Uesaka
- Center for Gene Research, Nagoya University, Nagoya, Japan
| | - Aiko Tanaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Daisuke Sugiura
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Motohiko Kondo
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- Motohiko Kondo
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27
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Ahmed W, Payyappat S, Cassidy M, Harrison N, Marinoni O, Besley C. Prevalence and abundance of traditional and host-associated fecal indicators in urban estuarine sediments: Potential implications for estuarine water quality monitoring. Water Res 2020; 184:116109. [PMID: 32818744 DOI: 10.1016/j.watres.2020.116109] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/25/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
This study aimed to determine the prevalence and abundance of sewage and animal fecal contamination of sediment at seven estuarine locations in Sydney, NSW, Australia. Sediment samples were tested for the occurrence of microbial targets including molecular marker genes of enterococci (ENT), Bacteroides HF183 (HF183), Methanobrevibacter smithii (nifH), human adenovirus (HAdV) and emerging sewage-associated marker genes crAssphage (CPQ_056) and Lachnospiraceae (Lachno3) and animal feces-associated marker genes, including avian feces-associated Helicobacter spp. (GFD), canine-feces associated Bacteroides (DogBact), cattle-feces associated (cowM2) and horse feces-associated Bacteroides (HoF597). Results from this study showed that urban estuarine sediment can act as a reservoir of fecal indicator bacteria (FIB) and several microbial source tracking (MST) marker genes, including previously unreported Lachno3. The sewage-associated marker gene CPQ_056 was most prevalent, in 63.8% of sediment samples, while the avian associated marker gene GFD had the highest mean abundance. The GFD marker gene was highly abundant and widely detected in sediment samples from all seven locations compared to the other animal feces-associated marker genes. In all, 31 (44.9%) sediment samples were positive for at least two sewage-associated marker genes. However, the non-quantifiable detection of the HAdV marker gene did not always align with the detection of two or more sewage-associated marker genes. In addition, the most frequent wet weather overflow exposure occurred at locations that did not have a consistent pattern of detection of the sewage-associated marker genes, suggesting sediments may not be a suitable measure of recent sewage contamination. To assist water quality and public health managers better understand past microbial contamination of estuarine sediment, further studies seem justified to explore the role of decay of MST marker genes in sediment. Further work is also needed on the role of resuspension of MST marker genes from sediment during storm events to the water column as a source of contamination for both the GFD and sewage-associated marker genes.
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Affiliation(s)
- Warish Ahmed
- CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Dutton Park, QLD, 4102, Australia.
| | - Sudhi Payyappat
- Sydney Water, 1 Smith Street, Parramatta, NSW, 2150, Australia
| | - Michele Cassidy
- Sydney Water, 1 Smith Street, Parramatta, NSW, 2150, Australia
| | - Nathan Harrison
- Sydney Water, 1 Smith Street, Parramatta, NSW, 2150, Australia
| | - Oswald Marinoni
- CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Dutton Park, QLD, 4102, Australia
| | - Colin Besley
- Sydney Water, 1 Smith Street, Parramatta, NSW, 2150, Australia
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28
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Yang Y, Liu L, Singh RP, Meng C, Ma S, Jing C, Li Y, Zhang C. Nodule and Root Zone Microbiota of Salt-Tolerant Wild Soybean in Coastal Sand and Saline-Alkali Soil. Front Microbiol 2020; 11:2178. [PMID: 33071999 PMCID: PMC7536311 DOI: 10.3389/fmicb.2020.523142] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 08/17/2020] [Indexed: 11/13/2022] Open
Abstract
Soil salinization limits crop growth and yield in agro-ecosystems worldwide by reducing soil health and altering the structure of microbial communities. Salt-tolerant plant growth-promoting rhizobacteria (PGPR) alleviate plant salinity stress. Wild soybean (Glycine soja Sieb. and Zucc.) is unique in agricultural ecosystems owing to its ability to grow in saline-alkali soils and fix atmospheric nitrogen via symbiotic interactions with diverse soil microbes. However, this rhizosphere microbiome and the nodule endosymbionts have not been investigated to identify PGPR. In this study, we investigated the structural and functional rhizosphere microbial communities in saline-alkali soil from the Yellow River Delta and coastal soil in China, as well as wild soybean root nodule endosymbionts. To reveal the composition of the microbial ecosystem, we performed 16S rRNA and nifH gene amplicon sequencing on root nodules and root zones under different environmental conditions. In addition, we used culture-independent methods to examine the root bacterial microbiome of wild soybean. For functional characterization of individual members of the microbiome and their impact on plant growth, we inoculated isolates from the root microbiome with wild soybean and observed nodulation. Sinorhizobium/Ensifer accounted for 97% of the root nodule microbiome, with other enriched members belonging to the phyla Actinobacteria, Bacteroidetes, Chloroflexi, Acidobacteria, and Gemmatimonadetes; the genera Sphingomonas, Microbacterium, Arthrobacter, Nocardioides, Streptomyces, Flavobacterium, Flavisolibacter, and Pseudomonas; and the family Enterobacteriaceae. Compared to saline-alkali soil from the Yellow River Delta, coastal soil was highly enriched for soybean nodules and displayed significant differences in the abundance and diversity of β-proteobacteria, δ-proteobacteria, Actinobacteria, and Bacteroidetes. Overall, the wild soybean root nodule microbiome was dominated by nutrient-providing Sinorhizobium/Ensifer and was enriched for bacterial genera that may provide salt resistance. Thus, this reductionist experimental approach provides an avenue for future systematic and functional studies of the plant root microbiome.
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Affiliation(s)
- Yingjie Yang
- Marine Agriculture Research Center, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Lei Liu
- Bureau of Agriculture and Rural Affairs of Laoshan District, Qingdao, China
| | - Raghvendra Pratap Singh
- Department of Research and Development, Biotechnology, Uttaranchal University, Dehradun, India
| | - Chen Meng
- Marine Agriculture Research Center, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Siqi Ma
- Marine Agriculture Research Center, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Changliang Jing
- Marine Agriculture Research Center, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Yiqiang Li
- Marine Agriculture Research Center, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Chengsheng Zhang
- Marine Agriculture Research Center, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
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Han LL, Wang Q, Shen JP, Di HJ, Wang JT, Wei WX, Fang YT, Zhang LM, He JZ. Multiple factors drive the abundance and diversity of the diazotrophic community in typical farmland soils of China. FEMS Microbiol Ecol 2020; 95:5531308. [PMID: 31295349 DOI: 10.1093/femsec/fiz113] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 07/10/2019] [Indexed: 11/12/2022] Open
Abstract
Biological nitrogen fixation plays an important role in nitrogen cycling by transferring atmospheric N2 to plant-available N in the soil. However, the diazotrophic activity and distribution in different types of soils remain to be further explored. In this study, 152 upland soils were sampled to examine the diazotrophic abundance, nitrogenase activity, diversity and community composition by quantitative polymerase chain reaction, acetylene reduction assay and the MiSeq sequencing of nifH genes, respectively. The results showed that diazotrophic abundance and nitrogenase activity varied among the three soil types. The diazotrophic community was mainly dominated by Bradyrhizobium, Azospirillum, Myxobacter, Desulfovibrio and Methylobacterium. The symbiotic diazotroph Bradyrhizobium was widely distributed among soils, while the distribution of free-living diazotrophs showed large variation and was greatly affected by multiple factors. Crop type and soil properties directly affected the diazotrophic ɑ-diversity, while soil properties, climatic factors and spatial distance together influenced the diazotrophic community. Network structures were completely different among all three types of soils, with most complex interactions observed in the Red soil. These findings suggest that diazotrophs have various activities and distributions in the three soil types, which played different roles in nitrogen input in agricultural soil in China, being driven by multiple environmental factors.
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Affiliation(s)
- Li-Li Han
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Qing Wang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.,Guangdong Key Laboratory of Sugarcane Improvement and Biorefinery, Guangdong Provincial Bioengineering Institute (Guangzhou Sugarcane Industry Research Institute), Guangzhou 510316, China
| | - Ju-Pei Shen
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Hong J Di
- Centre for Soil and Environmental Research, Lincoln University, Lincoln 7674, New Zealand
| | - Jun-Tao Wang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Wen-Xue Wei
- Key Laboratory of Agro-Ecological Processes in Subtropical Regions and Taoyuan Station of Agro-Ecology Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
| | - Yun-Ting Fang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Li-Mei Zhang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Ji-Zheng He
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.,University of the Chinese Academy of Sciences, Beijing 100049, China.,Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
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Gupta VVSR, Zhang B, Penton CR, Yu J, Tiedje JM. Diazotroph Diversity and Nitrogen Fixation in Summer Active Perennial Grasses in a Mediterranean Region Agricultural Soil. Front Mol Biosci 2019; 6:115. [PMID: 31750314 PMCID: PMC6848460 DOI: 10.3389/fmolb.2019.00115] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/11/2019] [Indexed: 12/16/2022] Open
Abstract
Summer-growing perennial grasses such as Panicum coloratum L. cv. Bambatsi (Bambatsi panic), Chloris gayana Kunth cv. Katambora (Rhodes grass) and Digitaria eriantha Steud. cv. Premier (Premier digit grass) growing in the poor fertility sandy soils in the Mediterranean regions of southern Australia and western Australia mainly depend upon soil N and biological N inputs through diazotrophic (free living or associative) N fixation. We investigated the community composition and diversity (nifH-amplicon sequencing), abundance (qPCR) and functional capacity (15N incubation assay) of the endophytic diazotrophic community in the below and above ground plant parts of field grown and unfertilized grasses. Results showed a diverse and abundant diazotrophic community inside plant both above and below-ground and there was a distinct diazotrophic assemblage in the different plant parts in all the three grasses. There was a limited difference in the diversity between leaves, stems and roots except that Panicum grass roots harbored greater species richness. Nitrogen fixation potentials ranged between 0.24 and 5.9 mg N kg-1 day-1 and N fixation capacity was found in both the above and below ground plant parts. Results confirmed previous reports of plant species-based variation and that Alpha-Proteobacteria were the dominant group of nifH-harboring taxa both in the belowground and aboveground parts of the three grass species. Results also showed a well-structured nifH-harboring community in all plant parts, an example for a functional endophytic community. Overall, the variation in the number and identity of module hubs and connectors among the different plant parts suggests that co-occurrence patterns within the nifH-harboring community specific to individual compartments and local environments of the niches within each plant part may dictate the overall composition of diazotrophs within a plant.
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Affiliation(s)
| | - Bangzhou Zhang
- Institute for Microbial Ecology, School of Medicine, Xiamen University, Xiamen, China
- Center for Microbial Ecology, Michigan State University, East Lansing, MI, United States
| | - Christopher Ryan Penton
- College of Integrative Sciences and Arts, Arizona State University, Mesa, AZ, United States
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Julian Yu
- College of Integrative Sciences and Arts, Arizona State University, Mesa, AZ, United States
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - James M. Tiedje
- Center for Microbial Ecology, Michigan State University, East Lansing, MI, United States
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Abstract
Azotobacters have been used as biofertilizer since more than a century. Azotobacters fix nitrogen aerobically, elaborate plant hormones, solubilize phosphates and also suppress phytopathogens or reduce their deleterious effect. Application of wild type Azotobacters results in better yield of cereals like corn, wheat, oat, barley, rice, pearl millet and sorghum, of oil seeds like mustard and sunflower, of vegetable crops like tomato, eggplant, carrot, chillies, onion, potato, beans and sugar beet, of fruits like mango and sugar cane, of fiber crops like jute and cotton and of tree like oak. In addition to the structural genes of the enzyme nitrogenase and of other accessory proteins, A. vinelandii chromosomes contain the regulatory genes nifL and nifA. NifA must bind upstream of the promoters of all nif operons for enabling their expression. NifL on activation by oxygen or ammonium, interacts with NifA and neutralizes it. Nitrogen fixation has been enhanced by deletion of nifL and by bringing nifA under the control of a constitutive promoter, resulting in a strain that continues to fix nitrogen in presence of urea fertilizer. Additional copies of nifH (the gene for the Fe-protein of nitrogenase) have been introduced into A. vinelandii, thereby augmenting nitrogen fixation. The urease gene complex ureABC has been deleted, the ammonia transport gene amtB has been disrupted and the expression of the glutamine synthase gene has been regulated to enhance urea and ammonia excretion. Gluconic acid has been produced by introducing the glucose dehydrogenase gene, resulting in enhanced solubilization of phosphate.
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Hrynkiewicz K, Patz S, Ruppel S. Salicornia europaea L. as an underutilized saline-tolerant plant inhabited by endophytic diazotrophs. J Adv Res 2019; 19:49-56. [PMID: 31341669 PMCID: PMC6630021 DOI: 10.1016/j.jare.2019.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 05/07/2019] [Accepted: 05/09/2019] [Indexed: 12/31/2022] Open
Abstract
Revealing of the community composition of diazotrophic endophytes of S. europaea. The abundance of bacterial diazotrophs in plant organs of S. europaea. Domination of endophytic diazotrophs from Actinobacteria in higher salinity. Indication of new diazotrophic species associated with halophytes. Selection of diazotrophic endophytes useful in agriculture.
Despite the great interest in using halophyte Salicornia europaea L. as a crop in extreme saline habitats, little is known about the role played by associated endophytic bacteria in increasing tolerance of the host-plant to nutrient deficiency. Main objectives of this study were to investigate the community composition of diazotrophic endophytes of S. europaea grown under natural conditions, and determine the proportion of plant-growth promoting bacterial strains able to fix N2. To quantify the abundance of diazotrophic bacterial endophytes in stems and roots of S. europaea, nifH gene and 16S rDNA copy numbers were assessed by quantitative real-time PCR, and characterized the taxonomic structure of cultivable bacteria based on selective medium for diazotrophs. The highest copy numbers of nifH and 16S rDNA were observed in the stems of plants growing at the test site characterized by lower salinity, and correlated with high N concentrations in plant tissues. The abundance of bacterial diazotrophs isolated from plant tissues ranged from 3.6 to 6.3 (log10 of cfu per gram dry plant tissue) and varied in a site- and plant-organ manner. Proteobacteria dominated in plants growing in lower salinity while Actinobacteria prevailed in plants originating from higher salinity, what suggest better adaptation of this group of bacteria to extreme salinity. The results provide insights into new species of diazotrophs associated with halophytes that can be used to optimize strategies for selecting biostimulants useful in saline soils.
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Affiliation(s)
- Katarzyna Hrynkiewicz
- Department of Microbiology, Faculty of Biology and Environmental Protection, N. Copernicus University in Torun, Lwowska 1, PL-87-100 Torun, Poland
| | - Sascha Patz
- Algorithms in Bioinformatics, Center for Bioinformatics, University of Tuebingen, Sand 14, D-72076 Tuebingen, Germany
| | - Silke Ruppel
- Leibniz Institute of Vegetable- and Ornamental Crops, Theodor-Echtermeyer-Weg 1, D-14979 Grossbeeren, Germany
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Qaisrani MM, Zaheer A, Mirza MS, Naqqash T, Qaisrani TB, Hanif MK, Rasool G, Malik KA, Ullah S, Jamal MS, Mirza Z, Karim S, Rasool M. A comparative study of bacterial diversity based on culturable and culture-independent techniques in the rhizosphere of maize ( Zea mays L.). Saudi J Biol Sci 2019; 26:1344-1351. [PMID: 31762594 PMCID: PMC6864194 DOI: 10.1016/j.sjbs.2019.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/22/2019] [Accepted: 03/31/2019] [Indexed: 11/29/2022] Open
Abstract
Objective Maize is an important crop for fodder, food and feed industry. The present study explores the plant-microbe interactions as alternative eco-friendly sustainable strategies to enhance the crop yield. Methodology Bacterial diversity was studied in the rhizosphere of maize by culture-dependent and culture-independent techniques by soil sampling, extraction of DNA, amplification of gene of interest, cloning of desired fragment and library construction. Results Culturable bacteria were identified as Achromobacter, Agrobacterium, Azospirillum, Bacillus, Brevibacillus, Bosea, Enterobacter, Microbacterium, Pseudomonas, Rhodococcus, Stenotrophomonas and Xanthomonas genera. For culture-independent approach, clone library of 16S ribosomal RNA gene was assembled and 100 randomly selected clones were sequenced. Majority of the sequences were related to Firmicutes (17%), Acidobacteria (16%), Actinobacteria (17%), Alpha-Proteobacteria (7%), Delta-proteobacteria (4.2%) and Gemmatimonadetes (4.2%) However, some of the sequences (30%) were novel that showed no homologies to phyla of cultured bacteria in the database. Diversity of diazotrophic bacteria in the rhizosphere investigated by analysis of PCR-amplified nifH gene sequence that revealed abundance of sequences belonging to genera Azoarcus (25%), Aeromonas (10%), Pseudomonas (10%). The diazotrophic genera Azotobacter, Agrobacterium and Zoogloea related nifH sequences were also detected but no sequence related to Azospirillum was found showing biasness of the growth medium rather than relative abundance of diazotrophs in the rhizosphere. Conclusion The study provides a foundation for future research on focussed isolation of the Azoarcus and other diazotrophs found in higher abundance in the rhizosphere.
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Affiliation(s)
- Muther Mansoor Qaisrani
- Department of Bioinformatics, Khwaja Fareed University of Engineering & IT, Rahim Yar Khan, Pakistan
| | - Ahmad Zaheer
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
| | - Muhammad Sajjad Mirza
- National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Tahir Naqqash
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | | | | | - Ghulam Rasool
- Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Pakistan
| | - Kauser Abdulla Malik
- Department of Biological Sciences, Forman Christian College (A Chartered University), Lahore, Pakistan
| | - Saleem Ullah
- Department of Bioinformatics, Khwaja Fareed University of Engineering & IT, Rahim Yar Khan, Pakistan
| | - Mohammad Sarwar Jamal
- King Fahd Medical Research Center (KFMRC), King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Zeenat Mirza
- King Fahd Medical Research Center (KFMRC), King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sajjad Karim
- Center of Excellence in Genomic Medicine Research (CEGMR), King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mahmood Rasool
- Center of Excellence in Genomic Medicine Research (CEGMR), King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
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Marques ELS, Dias JCT, Gross E, Silva ABCE, de Moura SR, Rezende RP. Purple Sulfur Bacteria Dominate Microbial Community in Brazilian Limestone Cave. Microorganisms 2019; 7:E29. [PMID: 30678083 DOI: 10.3390/microorganisms7020029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 11/16/2022] Open
Abstract
The mineralogical composition of caves makes the environment ideal for inhabitation by microbes. However, the bacterial diversity in the cave ecosystem remains largely unexplored. In this paper, we described the bacterial community in an oxic chamber of the Sopradeira cave, an iron-rich limestone cave, in the semiarid region of Northeast Brazil. The microbial population in the cave samples was studied by 16S rDNA next-generation sequencing. A type of purple sulfur bacteria (PSB), Chromatiales, was found to be the most abundant in the sediment (57%), gravel-like (73%), and rock samples (96%). The predominant PSB detected were Ectothiorhodospiraceae, Chromatiaceae, and Woeseiaceae. We identified the PSB in a permanently aphotic zone, with no sulfur detected by energy-dispersive X-ray (EDX) spectroscopy. The absence of light prompted us to investigate for possible nitrogen fixing (nifH) and ammonia oxidizing (amoA) genes in the microbial samples. The nifH gene was found to be present in higher copy numbers than the bacterial-amoA and archaeal-amoA genes, and archaeal-amoA dominated the ammonia-oxidizing community. Although PSB dominated the bacterial community in the samples and may be related to both nitrogen-fixing and ammonia oxidizing bacteria, nitrogen-fixing associated gene was the most detected in those samples, especially in the rock. The present work demonstrates that this cave is an interesting hotspot for the study of ammonia-oxidizing archaea and aphotic PSB.
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Du P, Wu X, Xu J, Dong F, Liu X, Zhang Y, Zheng Y. Clomazone influence soil microbial community and soil nitrogen cycling. Sci Total Environ 2018; 644:475-485. [PMID: 29990898 DOI: 10.1016/j.scitotenv.2018.06.214] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/17/2018] [Accepted: 06/17/2018] [Indexed: 06/08/2023]
Abstract
We designed an indoor mesocosm experiment to investigate the long-term effects of exposure to clomazone, a widely used herbicide, on soil microbial communities and their nitrogen (N) cycling functions. Clomazone was applied to two typical soils from China at three concentrations: 0.8 (the recommended dosage), 8 and 80 mg kg-1 soil dry weight, and the mix was incubated for 90 days. Samples were removed periodically for assay with several techniques. The half-lives of clomazone in this experiment were 11-126 d. Results were significant only for the highest clomazone concentration. Next-generation sequencing of the 16S and 18S rDNA genes revealed that bacterial diversity significantly decreased whereas fungal abundance increased after day 60 but with no detectable effect on the microbial community. Hierarchical cluster and principal coordinates analysis revealed that the bacterial community structure was negatively impacted. Linear discriminant analysis of effect size identified Sphingomonas and Arthrobacter as the predominant bacterial species. Finally, we measured soil NH4+ and NO3- concentrations and used real-time PCR to analyze the abundance of the N-cycling genes, nifH and amoA. In the first 30 days, the NO3--N content and the number of ammonia-oxidizing bacteria increased. N2-fixing bacteria were inhibited after 60 days, but the NH4+-N concentration remained unchanged and was likely provided by ammoniation.
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Affiliation(s)
- Pengqiang Du
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing 100193, China; College of Chemistry, Central China Normal University, No. 152 Luoyu Road, Wuhan 430079, China
| | - Xiaohu Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing 100193, China; Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-product Quality and Safety, Ministry of Agriculture and Rural Affairs of the People's Republic of China, China.
| | - Jun Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing 100193, China; Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agri-product Quality and Safety, Ministry of Agriculture and Rural Affairs of the People's Republic of China, China
| | - Fengshou Dong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing 100193, China
| | - Xingang Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing 100193, China
| | - Ying Zhang
- Institute of Plant Protection, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China
| | - Yongquan Zheng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing 100193, China
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Pedersen JN, Bombar D, Paerl RW, Riemann L. Diazotrophs and N 2-Fixation Associated With Particles in Coastal Estuarine Waters. Front Microbiol 2018; 9:2759. [PMID: 30505296 PMCID: PMC6250843 DOI: 10.3389/fmicb.2018.02759] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/29/2018] [Indexed: 11/13/2022] Open
Abstract
Putative heterotrophic bacteria carrying out N2-fixation, so-called non-cyanobacterial diazotrophs (NCDs), are widely distributed in marine waters, but details of how the O2-inhibited N2-fixation process is promoted in the oxic water column remains ambiguous. Here we carried out two experiments with water from a eutrophic temperate fjord to examine whether low-oxygen microenvironments within particulate organic matter could be loci suitable for N2-fixation. First, water enriched with natural particles or sediment showed higher N2-fixation rates than bulk water, and nitrogenase genes (nifH) revealed that specific diazotrophs were affiliated with the particulate matter. Second, pristine artificial surfaces were rapidly colonized by diverse bacteria, while putative diazotrophs emerged relatively late (after 80 h) during the colonization, and phylotypes related to Pseudomonas and to anaerobic bacteria became dominant with time. Our study pinpoints natural particles as sites of N2-fixation, and indicates that resuspension of sediment material can elevate pelagic N2-fixation. Moreover, we show that diverse natural diazotrophs can colonize artificial surfaces, but colonization by “pioneer” bacterioplankton that more rapidly associate with surfaces appears to be a prerequisite. Whereas our experimental study supports the idea of pelagic particles as sites of N2-fixation by heterotrophic bacteria, future in situ studies are needed in order to establish identity, activity and ecology of particle associated NCDs as a function of individual particle characteristics.
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Affiliation(s)
- Jeppe N Pedersen
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Deniz Bombar
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Ryan W Paerl
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
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Birnbaum C, Bissett A, Teste FP, Laliberté E. Symbiotic N 2-Fixer Community Composition, but Not Diversity, Shifts in Nodules of a Single Host Legume Across a 2-Million-Year Dune Chronosequence. Microb Ecol 2018; 76:1009-1020. [PMID: 29663039 DOI: 10.1007/s00248-018-1185-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 04/05/2018] [Indexed: 06/08/2023]
Abstract
Long-term soil age gradients are useful model systems to study how changes in nutrient limitation shape communities of plant root mutualists because they represent strong natural gradients of nutrient availability, particularly of nitrogen (N) and phosphorus (P). Here, we investigated changes in the dinitrogen (N2)-fixing bacterial community composition and diversity in nodules of a single host legume (Acacia rostellifera) across the Jurien Bay chronosequence, a retrogressive 2 million-year-old sequence of coastal dunes representing an exceptionally strong natural soil fertility gradient. We collected nodules from plants grown in soils from five chronosequence stages ranging from very young (10s of years; associated with strong N limitation for plant growth) to very old (> 2,000,000 years; associated with strong P limitation), and sequenced the nifH gene in root nodules to determine the composition and diversity of N2-fixing bacterial symbionts. A total of 335 unique nifH gene operational taxonomic units (OTUs) were identified. Community composition of N2-fixing bacteria within nodules, but not diversity, changed with increasing soil age. These changes were attributed to pedogenesis-driven shifts in edaphic conditions, specifically pH, exchangeable manganese, resin-extractable phosphate, nitrate and nitrification rate. A large number of common N2-fixing bacteria genera (e.g. Bradyrhizobium, Ensifer, Mesorhizobium and Rhizobium) belonging to the Rhizobiaceae family (α-proteobacteria) comprised 70% of all raw sequences and were present in all nodules. However, the oldest soils, which show some of the lowest soil P availability ever recorded, harboured the largest proportion of unclassified OTUs, suggesting a unique set of N2-fixing bacteria adapted to extreme P limitation. Our results show that N2-fixing bacterial composition varies strongly during long-term ecosystem development, even within the same host, and therefore rhizobia show strong edaphic preferences.
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Affiliation(s)
- Christina Birnbaum
- Environmental and Conservation Sciences, School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Perth, Western Australia, 6150, Australia.
- Department of Ecology and Evolutionary Biology, School of Science and Engineering, Tulane University, 6823 St Charles Ave, New Orleans, LA, 70118, USA.
| | | | - Francois P Teste
- Grupo de Estudios Ambientales, IMASL-CONICET & Universidad Nacional de San Luis, Av. Ejercito de los Andes 950, 5700, San Luis, Argentina
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, (Perth), Western Australia, 6009, Australia
| | - Etienne Laliberté
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, (Perth), Western Australia, 6009, Australia
- Centre sur la biodiversité, Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, 4101 Sherbrooke Est, Montréal, Quebec, H1X 2B2, Canada
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Kucho KI, Tobita H, Ikebe M, Shibata M, Imaya A, Kabeya D, Saitoh T, Okamoto T, Ono K, Morisada K. Frankia communities at revegetating sites in Mt. Ontake, Japan. Antonie Van Leeuwenhoek 2018; 112:91-99. [PMID: 30155663 DOI: 10.1007/s10482-018-1151-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/25/2018] [Indexed: 11/24/2022]
Abstract
In 1984 at Mt. Ontake in Japan, an earthquake caused a devastating landslide, and as a result, the vegetation on the south slope of the mountain was completely eliminated. In higher elevation (2000 m) areas, revegetation has not yet been completed even 30 years after the landslide. Revegetation progress throughout the area was heterogeneous. In the partially revegetated areas, actinorhizal plant species such as Alnus maximowiczii and Alnus matsumurae have been found. In the present study, we investigated the Frankia communities in the higher-elevation area using sequence analysis of the amplified nifH (dinitrogenase reductase) gene from nodule and soil samples collected in the disturbed region, undisturbed forest, and in the boundary between the disturbed region and the undisturbed forest. Phylogenetic analysis of partial nifH sequences revealed the presence of six clusters, each of which consisted of highly similar (> 99%) sequences. Four clusters showed significant sequence similarity to Frankia (three Alnus- and a Casuarina-infecting strains). Diversity in the Frankia community was relatively low-only one or two clusters were detected in a site. At most of the sampling sites, a dominant cluster in a nodule coincided with that in rhizosphere soil, indicating that community structure in the rhizosphere is a primary factor that determines occupancy in a nodule. No significant difference in community structure was observed between plant species. Diversity in the Frankia community varied depending on revegetation progress. Cluster A, which was the most dominant in the disturbed region, was likely to have invaded from undisturbed forest.
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Affiliation(s)
- Ken-Ichi Kucho
- Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, 890-0065, Japan.
| | - Hiroyuki Tobita
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, 305-8687, Japan
| | - Mari Ikebe
- Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, 890-0065, Japan
| | - Mitsue Shibata
- Department of Forest Vegetation, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, 305-8687, Japan
| | - Akihiro Imaya
- Forestry Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki, 305-8686, Japan
| | - Daisuke Kabeya
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, 305-8687, Japan
| | - Tomoyuki Saitoh
- Tohoku Research Center, Forestry and Forest Products Research Institute, 2-25 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate, 020-0123, Japan
| | - Toru Okamoto
- Kansai Research Center, Forestry and Forest Products Research Institute, 68 Nagaikyutaroh, Momoyama, Fushimi, Kyoto, 612-0855, Japan
| | - Kenji Ono
- Tohoku Research Center, Forestry and Forest Products Research Institute, 2-25 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate, 020-0123, Japan
| | - Kazuhito Morisada
- Department of Forest Soil, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, 305-8687, Japan
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Turk-Kubo KA, Connell P, Caron D, Hogan ME, Farnelid HM, Zehr JP. In Situ Diazotroph Population Dynamics Under Different Resource Ratios in the North Pacific Subtropical Gyre. Front Microbiol 2018; 9:1616. [PMID: 30090092 PMCID: PMC6068237 DOI: 10.3389/fmicb.2018.01616] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/28/2018] [Indexed: 11/13/2022] Open
Abstract
Major advances in understanding the diversity, distribution, and activity of marine N2-fixing microorganisms (diazotrophs) have been made in the past decades, however, large gaps in knowledge remain about the environmental controls on growth and mortality rates. In order to measure diazotroph net growth rates and microzooplankton grazing rates on diazotrophs, nutrient perturbation experiments and dilution grazing experiments were conducted using free-floating in situ incubation arrays in the vicinity of Station ALOHA in March 2016. Net growth rates for targeted diazotroph taxa as well as Prochlorococcus, Synechococcus and photosynthetic picoeukaryotes were determined under high (H) and low (L) nitrate:phosphate (NP) ratio conditions at four depths in the photic zone (25, 45, 75, and 100 m) using quantitative PCR and flow cytometry. Changes in the prokaryote community composition in response to HNP and LNP treatments were characterized using 16S rRNA variable region tag sequencing. Microzooplankton grazing rates on diazotrophs were measured using a modified dilution technique at two depths in the photic zone (15 and 125 m). Net growth rates for most of the targeted diazotrophs after 48 h were not stimulated as expected by LNP conditions, rather enhanced growth rates were often measured in HNP treatments. Interestingly, net growth rates of the uncultivated prymnesiophyte symbiont UCYN-A1 were stimulated in HNP treatments at 75 and 100 m, suggesting that N used for growth was acquired through continuing to fix N2 in the presence of nitrate. Net growth rates for UCYN-A1, UCYN-C, Crocosphaera sp. (UCYN-B) and the diatom symbiont Richelia (associated with Rhizosolenia) were uniformly high at 45 m (up to 1.6 ± 0.5 d-1), implying that all were growing optimally at the onset of the experiment at that depth. Differences in microzooplankton grazing rates on UCYN-A1 and UCYN-C in 15 m waters indicate that the grazer assemblage preyed preferentially on UCYN-A1. Deeper in the water column (125 m), both diazotrophs were grazed at substantial rates, suggesting grazing pressure may increase with depth in the photic zone. Constraining in situ diazotroph growth and mortality rates are important steps for improving parameterization for diazotrophs in global ecosystem models.
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Affiliation(s)
- Kendra A. Turk-Kubo
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Paige Connell
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - David Caron
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - Mary E. Hogan
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Hanna M. Farnelid
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden
| | - Jonathan P. Zehr
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
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Du P, Wu X, Xu J, Dong F, Liu X, Zheng Y. Effects of trifluralin on the soil microbial community and functional groups involved in nitrogen cycling. J Hazard Mater 2018; 353:204-213. [PMID: 29674095 DOI: 10.1016/j.jhazmat.2018.04.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 03/13/2018] [Accepted: 04/04/2018] [Indexed: 06/08/2023]
Abstract
Large amounts of trifluralin are applied each year for weed control; however, its effects on soil microbial communities and functions are unknown. Two agricultural soils, one silty loam and one silty clay were spiked with TFL (0, 0.84, 8.4, and 84 mg kg-1) and studied the effects using a laboratory microcosm approach. The half-lives were 44.19-61.83 d in all cases. Bacterial abundance increased 1.12-5.56 times by TFL, but the diversity decreased. From the next-generation sequencing results, TFL altered the bacterial community structure, which initially diverged from the control community structure, then recovered, and then diverged again. Linear discriminant analysis effect size indicated that Sphingomonas and Xanthomonadaceae were the predominant species on day 7 and 15 in TFL treatments. N2-fixing bacteria were initially increased, then decreased, and then recovered, and it was positively correlated with NH4+-N content. Compared with the control, ammonia-oxidizing bacteria were decreased by 25.51-92.63%, ammonia-oxidizing archaea were decreased by 17.12-85.21% (except day 7), and the NO3--N concentration was also inhibited. In contrast to bacteria, fungal abundance was inhibited without any observable effects on fungal diversity or community structure. These results suggest that TFL impacts soil bacterial community and alters functional microorganisms involved in soil N processing.
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Affiliation(s)
- Pengqiang Du
- College of Chemistry, Central China Normal University, No. 152 Luoyu Road, Wuhan, 430079, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing, 100193, China
| | - Xiaohu Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing, 100193, China
| | - Jun Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing, 100193, China
| | - Fengshou Dong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing, 100193, China.
| | - Xingang Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing, 100193, China.
| | - Yongquan Zheng
- College of Chemistry, Central China Normal University, No. 152 Luoyu Road, Wuhan, 430079, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Beijing, 100193, China.
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Grün AL, Straskraba S, Schulz S, Schloter M, Emmerling C. Long-term effects of environmentally relevant concentrations of silver nanoparticles on microbial biomass, enzyme activity, and functional genes involved in the nitrogen cycle of loamy soil. J Environ Sci (China) 2018; 69:12-22. [PMID: 29941247 DOI: 10.1016/j.jes.2018.04.013] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 04/13/2018] [Accepted: 04/13/2018] [Indexed: 05/14/2023]
Abstract
The increasing production and use of engineered silver nanoparticles (AgNP) in industry and private households are leading to increased concentrations of AgNP in the environment. An ecological risk assessment of AgNP is needed, but it requires understanding the long term effects of environmentally relevant concentrations of AgNP on the soil microbiome. Hence, the aim of this study was to reveal the long-term effects of AgNP on soil microorganisms. The study was conducted as a laboratory incubation experiment over a period of one year using a loamy soil and AgNP concentrations ranging from 0.01 to 1 mg AgNP/kg soil. The short term effects of AgNP were, in general, limited. However, after one year of exposure to 0.01 mg AgNP/kg, there were significant negative effects on soil microbial biomass (quantified by extractable DNA; p = 0.000) and bacterial ammonia oxidizers (quantified by amoA gene copy numbers; p = 0.009). Furthermore, the tested AgNP concentrations significantly decreased the soil microbial biomass, the leucine aminopeptidase activity (quantified by substrate turnover; p = 0.014), and the abundance of nitrogen fixing microorganisms (quantified by nifH gene copy numbers; p = 0.001). The results of the positive control with AgNO3 revealed predominantly stronger effects due to Ag+ ion release. Thus, the increasing toxicity of AgNP during the test period may reflect the long-term release of Ag+ ions. Nevertheless, even very low concentrations of AgNP caused disadvantages for the microbial soil community, especially for nitrogen cycling, and our results confirmed the risks of releasing AgNP into the environment.
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Affiliation(s)
- Anna-Lena Grün
- Faculty of Regional and Environmental Sciences, Department of Soil Science, University of Trier, Trier, Germany.
| | - Susanne Straskraba
- J.W. Goethe University, Institute of Molecular Biosciences, Frankfurt am Main, Germany
| | - Stefanie Schulz
- Research for Comparative Microbiome Analysis, Helmholtz Zentrum München, Oberschleissheim, Germany
| | - Michael Schloter
- Research for Comparative Microbiome Analysis, Helmholtz Zentrum München, Oberschleissheim, Germany; Chair for Soil Science, Technische Universität München, Freising, Germany
| | - Christoph Emmerling
- Faculty of Regional and Environmental Sciences, Department of Soil Science, University of Trier, Trier, Germany
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Yu Y, Zhang J, Petropoulos E, Baluja MQ, Zhu C, Zhu J, Lin X, Feng Y. Divergent Responses of the Diazotrophic Microbiome to Elevated CO 2 in Two Rice Cultivars. Front Microbiol 2018; 9:1139. [PMID: 29910783 PMCID: PMC5992744 DOI: 10.3389/fmicb.2018.01139] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 05/14/2018] [Indexed: 01/20/2023] Open
Abstract
The species-specific responses of plant growth to elevated atmospheric CO2 concentration (eCO2) could lead to N limitation and potentially influence the sustainability of ecosystem. Questions remain unanswered with regards to the response of soil N2-fixing community to eCO2 when developing high-yielding agroecosystem to dampen the future rate of increase in CO2 levels and associated climate warming. This study demonstrates the divergent eCO2 influences on the paddy diazotrophic community between weak- and strong-responsive rice cultivars. In response to eCO2, the diazotrophic abundance increased more for the strong-responsive cultivar treatments than for the weak-responsive ones. Only the strong-responsive cultivars decreased the alpha diversity and separated the composition of diazotrophic communities in response to eCO2. The topological indices of the ecological networks further highlighted the different co-occurrence patterns of the diazotrophic microbiome in rice cultivars under eCO2. Strong-responsive cultivars destabilized the diazotrophic community by complicating and centralizing the co-occurrence network as well as by shifting the hub species from Bradyrhizobium to Dechloromonas in response to eCO2. On the contrary, the network pattern of the weak-responsive cultivars was simplified and decentralized in response to eCO2, with the hub species shifting from Halorhodospira under aCO2 to Sideroxydans under eCO2. Collectively, the above information indicates that the strong-responsive cultivars could potentially undermine the belowground ecosystem from the diazotrophs perspective in response to eCO2. This information highlights that more attention should be paid to the stability of the belowground ecosystem when developing agricultural strategies to adapt prospective climatic scenarios by growing high-yielding crop cultivars under eCO2.
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Affiliation(s)
- Yongjie Yu
- College of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jianwei Zhang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | | | - Marcos Q. Baluja
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Chunwu Zhu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Jianguo Zhu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Xiangui Lin
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Youzhi Feng
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
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Wang M, Veldsink JH, Dini-Andreote F, Salles JF. Compositional and abundance changes of nitrogen-cycling genes in plant-root microbiomes along a salt marsh chronosequence. Antonie Van Leeuwenhoek 2018; 111:2061-78. [PMID: 29846874 DOI: 10.1007/s10482-018-1098-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/14/2018] [Indexed: 10/14/2022]
Abstract
Disentangling the relative influences of soil properties and plant-host on root-associated microbiomes in natural systems is challenging, given that spatially segregated soil types display distinct historical legacies. In addition, distant locations may also lead to biogeographical patterns of microbial communities. Here, we used an undisturbed salt marsh chronosequence spanning over a century of ecosystem development to investigate changes in the community composition and abundance of a set of nitrogen-cycling genes. Specifically, we targeted genes of diazotrophs and ammonia oxidizers associated with the bulk and rhizosphere soil of the plant species Limonium vulgare. Samples were collected across five distinct successional stages of the chronosequence (ranging from 5 to 105 years) at two time-points. Our results indicate that soil variables such as sand:silt:clay % content and pH strongly relates to the abundance of N-cycling genes in the bulk soil. However, in the rhizosphere samples, the abundance of ammonia-oxidizing organisms (both bacteria and archaea, AOB and AOA, respectively) was relatively constant across most of the successional stages, albeit displaying seasonal variation. This result indicates a potentially stronger control of plant host (rather than soil) on the abundance of these organisms. Interestingly, the plant host did not have a significant effect on the composition of AOA and AOB communities, being mostly divergent according to soil successional stages. The abundance of diazotrophic communities in rhizosphere samples was more affected by seasonality than those of bulk soil. Moreover, the abundance pattern of diazotrophs in the rhizosphere related to the systematic increase of plant biomass and soil organic matter along the successional gradient. These results suggest a potential season-dependent regulation of diazotrophs exerted by the plant host. Overall, this study contributes to a better understanding of how the natural formation of a soil and host plants influence the compositional and abundance changes of nitrogen-cycling genes in bulk and rhizosphere soil microhabitats.
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Abstract
Semi-selective enrichment, followed by PCR screening, resulted in the successful direct isolation of fast-growing Rhizobia from a dryland agricultural soil. Over 50% of these isolates belong to the genus Neorhizobium, as concluded from partial rpoB and near-complete 16S rDNA sequence analysis. Further genotypic and genomic analysis of five representative isolates confirmed that they form a coherent group within Neorhizobium, closer to N. galegae than to the remaining Neorhizobium species, but clearly differentiated from the former, and constituting at least one new genomospecies within Neorhizobium. All the isolates lacked nod and nif symbiotic genes but contained a repABC replication/maintenance region, characteristic of rhizobial plasmids, within large contigs from their draft genome sequences. These repABC sequences were related, but not identical, to repABC sequences found in symbiotic plasmids from N. galegae, suggesting that the non-symbiotic isolates have the potential to harbor symbiotic plasmids. This is the first report of non-symbiotic members of Neorhizobium from soil.
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Affiliation(s)
- Amalia Soenens
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain
| | - Juan Imperial
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Pozuelo de Alarcón, Madrid, Spain.,Instituto de Ciencias Agrarias, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Caton IR, Caton TM, Schneegurt MA. Nitrogen-fixation activity and the abundance and taxonomy of nifH genes in agricultural, pristine, and urban prairie stream sediments chronically exposed to different levels of nitrogen loading. Arch Microbiol 2018; 200:623-633. [PMID: 29333588 PMCID: PMC5908754 DOI: 10.1007/s00203-018-1475-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 12/13/2017] [Accepted: 01/03/2018] [Indexed: 10/18/2022]
Abstract
Small streams exert great influences on the retention and attenuation of nitrogen (N) within stream networks. Human land use can lead to increased transport of dissolved inorganic N compounds and downstream eutrophication. Microbial activity in streams is important for maintaining an actively functioning N cycle. Chronically high N loading in streams affects the rates of the central processes of the N cycle by increasing rates of nitrification and denitrification, with biota exhibiting decreased efficiency of N use. The LINXII project measured N-cycle parameters in small streams using 15NO3- tracer release experiments. We concurrently measured N2 fixation rates in six streams of three types (agricultural, pristine, and urban prairie streams) as part of this broader study of major N-cycle processes. Nitrogen fixation in streams was significantly negatively correlated with nitrate levels, dissolved inorganic N levels, and denitrification rates. Algal mat and leaf litter samples generally exhibited the highest rates of N2 fixation. The abundance of nifH genes, as measured by real-time PCR, was marginally correlated with N2-fixation rates, but not to other N-cycle processes or stream characteristics. The nifH sequences observed were assigned to cyanobacteria, Deltaproteobacteria, Methylococcus, and Rhizobia. Seasonal changes, disturbances, and varying inputs may encourage a diverse, flexible, stable N2-fixing guild. Patchiness in the streams should be considered when assessing the overall impact of N2 fixation, since algal biomass exhibited high rates of N2 fixation.
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Affiliation(s)
- Ingrid R Caton
- Department of Biological Sciences, Wichita State University, 1845 Fairmount, Wichita, KS, 67260, USA
- Bio-Rad Laboratories, Vacaville, CA, 95688, USA
| | - Todd M Caton
- Department of Biological Sciences, Wichita State University, 1845 Fairmount, Wichita, KS, 67260, USA
| | - Mark A Schneegurt
- Department of Biological Sciences, Wichita State University, 1845 Fairmount, Wichita, KS, 67260, USA.
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Yin Y, Gu J, Wang X, Zhang K, Hu T, Ma J, Wang Q. Impact of copper on the diazotroph abundance and community composition during swine manure composting. Bioresour Technol 2018; 255:257-265. [PMID: 29428780 DOI: 10.1016/j.biortech.2018.01.120] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/23/2018] [Accepted: 01/24/2018] [Indexed: 06/08/2023]
Abstract
Biological nitrogen fixation is a major pathway in ecosystems. This study investigated the effects of adding Cu at different levels (0, 200, and 2000 mg kg-1) on the diazotroph community during swine manure composting. Quantitative PCR and high-throughput sequencing were used to analyze the abundances of diazotrophs and the community composition based on the nifH gene. The nifH gene copy number was relatively high in the early stage of composting and Cu had a significant inhibitory effect on the nifH copy number. Furthermore, Cu decreased the diversity of nifH and changed the microbial community structure in the early stage. The nifH genes from members of Firmicutes and Clostridium were most abundant. Co-occurrence ecological network analysis showed that the Cu treatments affected the co-occurrence patterns of diazotroph communities and reduced the associations between different diazotrophs. Interestingly, Cu may weaken symbiotic diazotrophic interactions and enhance the roles of free-living diazotrophs.
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Affiliation(s)
- Yanan Yin
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China
| | - Jie Gu
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China; Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Xiaojuan Wang
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China; Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Kaiyu Zhang
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China
| | - Ting Hu
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China
| | - Jiyue Ma
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China
| | - Qianzhi Wang
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China
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Henke BA, Turk-Kubo KA, Bonnet S, Zehr JP. Distributions and Abundances of Sublineages of the N 2-Fixing Cyanobacterium Candidatus Atelocyanobacterium thalassa (UCYN-A) in the New Caledonian Coral Lagoon. Front Microbiol 2018; 9:554. [PMID: 29674998 PMCID: PMC5895702 DOI: 10.3389/fmicb.2018.00554] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 03/12/2018] [Indexed: 11/21/2022] Open
Abstract
Nitrogen (N2) fixation is a major source of nitrogen that supports primary production in the vast oligotrophic areas of the world’s oceans. The Western Tropical South Pacific has recently been identified as a hotspot for N2 fixation. In the Noumea lagoon (New Caledonia), high abundances of the unicellular N2-fixing cyanobacteria group A (UCYN-A), coupled with daytime N2 fixation rates associated with the <10 μm size fraction, suggest UCYN-A may be an important diazotroph (N2-fixer) in this region. However, little is known about the seasonal variability and diversity of UCYN-A there. To assess this, surface waters from a 12 km transect from the mouth of the Dumbea River to the Dumbea Pass were sampled monthly between July 2012 and March 2014. UCYN-A abundances for two of the defined sublineages, UCYN-A1 and UCYN-A2, were quantified using qPCR targeting the nifH gene, and the nifH-based diversity of UCYN-A was characterized by identifying oligotypes, alternative taxonomic units defined by nucleotide positions with high variability. UCYN-A abundances were dominated by the UCYN-A1 sublineage, peaked in September and October and could be predicted by a suite of nine environmental parameters. At the sublineage level, UCYN-A1 abundances could be predicted based on lower temperatures (<23°C), nitrate concentrations, precipitation, wind speed, while UCYN-A2 abundances could be predicted based on silica, and chlorophyll a concentrations, wind direction, precipitation, and wind speed. Using UCYN-A nifH oligotyping, similar environmental variables explained the relative abundances of sublineages and their associated oligotypes, with the notable exception of the UCYN-A2 oligotype (oligo43) which had relative abundance patterns distinct from the dominant UCYN-A2 oligotype (oligo3). The results support an emerging pattern that UCYN-A is comprised of a diverse group of strains, with sublineages that may have different ecological niches. By identifying environmental factors that influence the composition and abundance of UCYN-A sublineages, this study helps to explain global UCYN-A abundance patterns, and is important for understanding the significance of N2 fixation at local and global scales.
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Affiliation(s)
- Britt A Henke
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Kendra A Turk-Kubo
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Sophie Bonnet
- IRD, MIO, UM 110 - IRD Centre of Noumea, Aix-Marseille University, University of South Toulon Var, CNRS/INSU, Noumea, France
| | - Jonathan P Zehr
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
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Ben Tekaya S, Guerra T, Rodriguez D, Dawson JO, Hahn D. Frankia Diversity in Host Plant Root Nodules Is Independent of Abundance or Relative Diversity of Frankia Populations in Corresponding Rhizosphere Soils. Appl Environ Microbiol 2018; 84:e02248-17. [PMID: 29247058 DOI: 10.1128/AEM.02248-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/09/2017] [Indexed: 12/17/2022] Open
Abstract
Actinorhizal plants form nitrogen-fixing root nodules in symbiosis with soil-dwelling actinobacteria within the genus Frankia, and specific Frankia taxonomic clusters nodulate plants in corresponding host infection groups. In same-soil microcosms, we observed that some host species were nodulated (Alnus glutinosa, Alnus cordata, Shepherdia argentea, Casuarina equisetifolia) while others were not (Alnus viridis, Hippophaë rhamnoides). Nodule populations were represented by eight different sequences of nifH gene fragments. Two of these sequences characterized frankiae in S. argentea nodules, and three others characterized frankiae in A. glutinosa nodules. Frankiae in A. cordata nodules were represented by five sequences, one of which was also found in nodules from A. glutinosa and C. equisetifolia, while another was detected in nodules from A. glutinosa Quantitative PCR assays showed that vegetation generally increased the abundance of frankiae in soil, independently of the target gene (i.e., nifH or the 23S rRNA gene). Targeted Illumina sequencing of Frankia-specific nifH gene fragments detected 24 unique sequences from rhizosphere soils, 4 of which were also found in nodules, while the remaining 4 sequences in nodules were not found in soils. Seven of the 24 sequences from soils represented >90% of the reads obtained in most samples; the 2 most abundant sequences from soils were not found in root nodules, and only 2 of the sequences from soils were detected in nodules. These results demonstrate large differences between detectable Frankia populations in soil and those in root nodules, suggesting that root nodule formation is not a function of the abundance or relative diversity of specific Frankia populations in soils.IMPORTANCE The nitrogen-fixing actinobacterium Frankia forms root nodules on actinorhizal plants, with members of specific Frankia taxonomic clusters nodulating plants in corresponding host infection groups. We assessed Frankia diversity in root nodules of different host plant species, and we related specific populations to the abundance and relative distribution of indigenous frankiae in rhizosphere soils. Large differences were observed between detectable Frankia populations in soil and those in root nodules, suggesting that root nodule formation is not a function of the abundance or relative diversity of specific Frankia populations in soils but rather results from plants potentially selecting frankiae from the soil for root nodule formation. These data also highlight the necessity of using a combination of different assessment tools so as to adequately address methodological constraints that could produce contradictory data sets.
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Duval C, Thomazeau S, Drelin Y, Yéprémian C, Bouvy M, Couloux A, Troussellier M, Rousseau F, Bernard C. Phylogeny and salt-tolerance of freshwater Nostocales strains: Contribution to their systematics and evolution. Harmful Algae 2018; 73:58-71. [PMID: 29602507 DOI: 10.1016/j.hal.2018.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/06/2018] [Accepted: 01/21/2018] [Indexed: 06/08/2023]
Abstract
Phylogenetic relationships among heterocytous genera (the Nostocales order) have been profoundly modified since the use of polyphasic approaches that include molecular data. There is nonetheless still ample scope for improving phylogenetic delineations of genera with broad ecological distributions, particularly by integrating specimens from specific or up-to-now poorly sampled habitats. In this context, we studied 36 new isolates belonging to Chrysosporum, Dolichospermum, Anabaena, Anabaenopsis, and Cylindrospermopsis from freshwater ecosystems of Burkina-Faso, Senegal, and Mayotte Island. Studying strains from these habitats is of particular interest as we suspected different range of salt variations during underwent periods of drought in small ponds and lakes. Such salt variation may cause different adaptation to salinity. We then undertook a polyphasic approach, combining molecular phylogenies, morphological analyses, and physiological measurements of tolerance to salinity. Molecular phylogenies of 117 Nostocales sequences showed that the 36 studied strains were distributed in seven lineages: Dolichospermum, Chrysosporum, Cylindrospermopsis/Raphidiopsis, Anabaenopsis, Anabaena sphaerica var tenuis/Sphaerospermopsis, and two independent Anabaena sphaerica lineages. Physiological data were congruent with molecular results supporting the separation into seven lineages. In an evolutionary context, salinity tolerance can be used as an integrative marker to reinforce the delineation of some cyanobacterial lineages. The history of this physiological trait contributes to a better understanding of processes leading to the divergence of cyanobacteria. In this study, most of the cyanobacterial strains isolated from freshwater environments were salt-tolerant, thus suggesting this trait constituted an ancestral trait of the heterocytous cyanobacteria and that it was probably lost two times secondarily and independently in the ancestor of Dolichospermum and of Cylindrospermopsis.
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Affiliation(s)
- Charlotte Duval
- UMR 7245 MCAM CNRS-MNHN, Muséum National d'Histoire Naturelle, CNRS, CP 39, 12 rue Buffon, F-75231 Paris Cedex 05, France
| | - Solène Thomazeau
- UMR 7245 MCAM CNRS-MNHN, Muséum National d'Histoire Naturelle, CNRS, CP 39, 12 rue Buffon, F-75231 Paris Cedex 05, France
| | - Yannick Drelin
- UMR 7245 MCAM CNRS-MNHN, Muséum National d'Histoire Naturelle, CNRS, CP 39, 12 rue Buffon, F-75231 Paris Cedex 05, France
| | - Claude Yéprémian
- UMR 7245 MCAM CNRS-MNHN, Muséum National d'Histoire Naturelle, CNRS, CP 39, 12 rue Buffon, F-75231 Paris Cedex 05, France
| | - Marc Bouvy
- UMR 9190 MARBEC, Université de Montpellier, CNRS, IRD Ifremer, CP 093, Place Eugène Bataillon, F-34095 Montpellier Cedex 5, France
| | - Arnaud Couloux
- Genoscope, Centre national de séquençage, 2, rue Gaston Crémieux, CP 5706, F-91057 Évry Cedex, France
| | - Marc Troussellier
- UMR 9190 MARBEC, Université de Montpellier, CNRS, IRD Ifremer, CP 093, Place Eugène Bataillon, F-34095 Montpellier Cedex 5, France
| | - Florence Rousseau
- UMR 7138ISYEB, Muséum National d'Histoire Naturelle, UPMC, CNRS, EPHE, CP39, 12 rue Buffon, F-75231 Paris Cedex 05, France
| | - Cécile Bernard
- UMR 7245 MCAM CNRS-MNHN, Muséum National d'Histoire Naturelle, CNRS, CP 39, 12 rue Buffon, F-75231 Paris Cedex 05, France.
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Dong M, Yang Z, Cheng G, Peng L, Xu Q, Xu J. Diversity of the Bacterial Microbiome in the Roots of Four Saccharum Species: S. spontaneum, S. robustum, S. barberi, and S. officinarum. Front Microbiol 2018. [PMID: 29515548 PMCID: PMC5826347 DOI: 10.3389/fmicb.2018.00267] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Endophytic bacteria are nearly ubiquitously present in the internal tissues of plants, and some endophytes can promote plant growth. In this study, we sampled the roots of four ancestral species of sugarcane (two genotypes per species) and two sugarcane cultivars, and used 16S rRNA and nifH gene sequencing to characterize the root endophytic bacterial communities and diazotroph diversity. A total of 7,198 operational taxonomic units (OTUs) were detected for the endophytic bacteria community. The endophytic bacterial communities exhibited significantly different α- and β-diversities. From the 202 detected families in the sugarcane roots, a core microbiome containing 13 families was identified. The nifH gene was successfully detected in 9 of 30 samples from the four sugarcane species assayed, and 1,734 OTUs were merged for endophytic diazotrophs. In the tested samples, 43 families of endophytic diazotrophs were detected, and six families showed differences across samples. Among the 20 most abundant detected genera, 10 have been reported to be involved in nitrogen fixation in sugarcane. These findings demonstrate the diversity of the microbial communities in different sugarcane germplasms and shed light on the mechanism of biological nitrogen fixation in sugarcane.
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Affiliation(s)
- Meng Dong
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zongtao Yang
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guangyuan Cheng
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lei Peng
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qian Xu
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jingsheng Xu
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, China
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