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Lang-Yona N, Alster A, Cummings D, Freiman Z, Kaplan-Levy R, Lupu A, Malinsky-Rushansky N, Ninio S, Sukenik A, Viner-Mozzini Y, Zohary T. Gloeotrichia pisum in Lake Kinneret: A successful epiphytic cyanobacterium. JOURNAL OF PHYCOLOGY 2023; 59:97-110. [PMID: 36371652 DOI: 10.1111/jpy.13301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
With climate change and re-oligotrophication of lakes due to restoration efforts, the relative importance of benthic cyanobacteria is increasing, but they are much less studied than their planktonic counterparts. Following a major water level rise event that inundated massive reed stands in Lake Kinneret, Israel, we discovered the appearance of a vast abundance of Gloeotrichia pisum (cyanobacteria). This provided an opportunity to investigate the biology and ecology of a benthic epiphytic colonial cyanobacterium, proliferating under altered environmental conditions, with possible toxin production potential and as a model for an invasive epiphyte. The species was identified by its typical morphology, and by sequencing its 16S rRNA gene and the intragenic space. We report on the abundance and spatial distribution of the detected colonies, their morphological characteristics, and pigment composition. High phycoerythrin content provides a brownish color and supports growth at low light levels. Genomic community composition analysis revealed that G. pisum colonies host a diverse microbial community of microalgae, cyanobacteria, bacteria, and archaea with a conserved and characteristic taxonomic composition. The Synechococcales order showed high relative abundance in the colony, as well as other prokaryotes producing secondary metabolites, such as the rhodopsin producer Pseudorhodobacter. The microbial consortium in the colonies performed nitrogen fixation. The diazotroph's phylogenetic relations were demonstrated. Tests for the presence of cyanotoxins (microcystin and cylindrospermopsin) proved negative. This study is the first documentation of this genus in Israel, providing insights into the invasive nature of G. pisum and the ecological implications of its appearance in a lake ecosystem.
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Affiliation(s)
- Naama Lang-Yona
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | - Alla Alster
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | - David Cummings
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | - Zohar Freiman
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | - Ruth Kaplan-Levy
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | - Achsa Lupu
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | | | - Shira Ninio
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | - Assaf Sukenik
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | - Yehudith Viner-Mozzini
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
| | - Tamar Zohary
- Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, 14950, Israel
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Kamran M, Imran QM, Ahmed MB, Falak N, Khatoon A, Yun BW. Endophyte-Mediated Stress Tolerance in Plants: A Sustainable Strategy to Enhance Resilience and Assist Crop Improvement. Cells 2022; 11:cells11203292. [PMID: 36291157 PMCID: PMC9600683 DOI: 10.3390/cells11203292] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 10/09/2022] [Accepted: 10/14/2022] [Indexed: 11/16/2022] Open
Abstract
Biotic and abiotic stresses severely affect agriculture by affecting crop productivity, soil fertility, and health. These stresses may have significant financial repercussions, necessitating a practical, cost-effective, and ecologically friendly approach to lessen their negative impacts on plants. Several agrochemicals, such as fertilizers, pesticides, and insecticides, are used to improve plant health and protection; however, these chemical supplements have serious implications for human health. Plants being sessile cannot move or escape to avoid stress. Therefore, they have evolved to develop highly beneficial interactions with endophytes. The targeted use of beneficial plant endophytes and their role in combating biotic and abiotic stresses are gaining attention. Therefore, it is important to experimentally validate these interactions and determine how they affect plant fitness. This review highlights research that sheds light on how endophytes help plants tolerate biotic and abiotic stresses through plant–symbiont and plant–microbiota interactions. There is a great need to focus research efforts on this vital area to achieve a system-level understanding of plant–microbe interactions that occur naturally.
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Affiliation(s)
- Muhammad Kamran
- School of Molecular Sciences, The University of Western Australia, M310, 35 Stirling Hwy, Perth, WA 6009, Australia
- Correspondence: (M.K.); (B.-W.Y.)
| | - Qari Muhammad Imran
- Department of Medical Biochemistry & Biophysics, Umea University, 90187 Umea, Sweden
- Laboratory of Plant Molecular Pathology and Functional Genomics, Division of Plant Biosciences, College of Agriculture and & Life Science, Kyungpook National University, Daegu 41566, Korea
| | - Muhammad Bilal Ahmed
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Korea
| | - Noreen Falak
- Laboratory of Plant Molecular Pathology and Functional Genomics, Division of Plant Biosciences, College of Agriculture and & Life Science, Kyungpook National University, Daegu 41566, Korea
| | - Amna Khatoon
- Department of Botany, Kohat University of Science and Technology, Kohat 26000, Pakistan
| | - Byung-Wook Yun
- Laboratory of Plant Molecular Pathology and Functional Genomics, Division of Plant Biosciences, College of Agriculture and & Life Science, Kyungpook National University, Daegu 41566, Korea
- Correspondence: (M.K.); (B.-W.Y.)
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Choi B, Kim TM, Jeong S, Kim Y, Kim E. Effects of Seed Endophytic Bacteria on Life History and Reproductive Traits in a Cosmopolitan Weed, Capsella bursa-pastoris. PLANTS (BASEL, SWITZERLAND) 2022; 11:2642. [PMID: 36235508 PMCID: PMC9570735 DOI: 10.3390/plants11192642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/27/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Diverse bacteria inhabit plant seeds, and at least some of them can enhance plant performance at the early developmental stage. However, it is still inconclusive whether seed bacteria can influence post-germination traits and their contribution to plant fitness. To explore the evolutionary and ecological consequences of seed endophytic bacteria, we isolated four bacterial strains from the seeds of an annual weedy plant species, Capsella bursa-pastoris, and conducted a common garden experiment using seeds inoculated by isolated bacteria. Seeds infected by bacteria tended to germinate in spring rather than in autumn. Bacterial treatment also altered the expression of plant life history and reproductive traits, including flowering dates, rosette diameter at bolting, number of inflorescences, and fruit production. The results of the path analyses suggested that such effects of bacterial treatments were due to bacterial inoculation as well as germination delayed until spring. Spring germinants with bacterial infection showed a weaker association between post-germination traits and relative fitness than those without bacterial infection. These results suggest that seed bacteria likely affect the expression of post-germination traits directly or indirectly by delaying the germination season. An altered contribution of plant traits to relative fitness implies the influence of seed bacteria on the strength of natural selection.
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Identification of the bacteria associated to the phycosphere of the Chlorella-like strain SEC_LI_ChL_1. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Verma SK, Chen Q, White JF. Evaluation of colonization and mutualistic endophytic symbiosis of Escherichia coli with tomato and Bermuda grass seedlings. PeerJ 2022; 10:e13879. [PMID: 35971430 PMCID: PMC9375544 DOI: 10.7717/peerj.13879] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 07/19/2022] [Indexed: 01/18/2023] Open
Abstract
Escherichia coli is generally considered a bacterium associated with animal microbiomes. However, we present evidence that E. coli may also mutualistically colonize roots of plant species, even to the extent that it may become endophytic in plants. In this study we used GFP tagged E. coli to observe its colonization and effects on tomato (Solanum lycopersicum) and Bermuda grass (Cynodon dactylon) seedling development and growth. Inoculation with the bacterium significantly improved root development of both seedlings tested. Treatment also increased the photosynthetic pigments in Bermuda grass seedlings. However, effects on shoot length in both seedlings were not significant. This bacterium was found to produce indole acetic acid (IAA) up to 8.68 ± 0.43 µg ml-1 in the broth medium amended with tryptophan. Effects on seedling root growth could, in part, be explained by IAA production. Bacteria successfully colonized the root surfaces and interiors of both seedlings. Tagged bacteria expressing the GFP were observed in the vascular tissues of Bermuda grass seedling roots. Seedlings with bacteria showed greater survival and were healthier than seedlings without bacteria, indicating that E. coli set up a successful mutualistic symbiosis with seedlings. E. coli is not commonly considered to be a plant endophyte but is more generally considered to be a crop contaminant. In this study we show that E. coli may also be an endophyte in plant tissues.
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Affiliation(s)
- Satish K. Verma
- Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Qiang Chen
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, United States of America
| | - James Francis White
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, United States of America
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Micci A, Zhang Q, Chang X, Kingsley K, Park L, Chiaranunt P, Strickland R, Velazquez F, Lindert S, Elmore M, Vines PL, Crane S, Irizarry I, Kowalski KP, Johnston-Monje D, White JF. Histochemical Evidence for Nitrogen-Transfer Endosymbiosis in Non-Photosynthetic Cells of Leaves and Inflorescence Bracts of Angiosperms. BIOLOGY 2022; 11:biology11060876. [PMID: 35741397 PMCID: PMC9220352 DOI: 10.3390/biology11060876] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/15/2022] [Accepted: 06/01/2022] [Indexed: 12/13/2022]
Abstract
Simple Summary We used light and confocal microscopy to visualize bacteria in leaf and bract cells of more than 30 species in 18 families of seed plants. We detected chemical exchanges between intracellular bacteria and plant cells. We found that endophytic bacteria that show evidence of the transfer of nitrogen to plants are present in non-photosynthetic cells of leaves and bracts of diverse plant species. Nitrogen transfer from bacteria was observed in epidermal cells, various filamentous and glandular trichomes, and other non-photosynthetic cells. The most efficient of the nitrogen-transfer endosymbioses were seen to involve glandular trichomes, as seen in hops (Humulus lupulus) and hemp (Cannabis sativa). Trichome chemistry is hypothesized to function to scavenge oxygen around bacteria to facilitate nitrogen fixation. Abstract We used light and confocal microscopy to visualize bacteria in leaf and bract cells of more than 30 species in 18 families of seed plants. Through histochemical analysis, we detected hormones (including ethylene and nitric oxide), superoxide, and nitrogenous chemicals (including nitric oxide and nitrate) around bacteria within plant cells. Bacteria were observed in epidermal cells, various filamentous and glandular trichomes, and other non-photosynthetic cells. Most notably, bacteria showing nitrate formation based on histochemical staining were present in glandular trichomes of some dicots (e.g., Humulus lupulus and Cannabis sativa). Glandular trichome chemistry is hypothesized to function to scavenge oxygen around bacteria and reduce oxidative damage to intracellular bacterial cells. Experiments to assess the differential absorption of isotopic nitrogen into plants suggest the assimilation of nitrogen into actively growing tissues of plants, where bacteria are most active and carbohydrates are more available. The leaf and bract cell endosymbiosis types outlined in this paper have not been previously reported and may be important in facilitating plant growth, development, oxidative stress resistance, and nutrient absorption into plants. It is unknown whether leaf and bract cell endosymbioses are significant in increasing the nitrogen content of plants. From the experiments that we conducted, it is impossible to know whether plant trichomes evolved specifically as organs for nitrogen fixation or if, instead, trichomes are structures in which bacteria easily colonize and where some casual nitrogen transfer may occur between bacteria and plant cells. It is likely that the endosymbioses seen in leaves and bracts are less efficient than those of root nodules of legumes in similar plants. However, the presence of endosymbioses that yield nitrate in plants could confer a reduced need for soil nitrogen and constitute increased nitrogen-use efficiency, even if the actual amount of nitrogen transferred to plant cells is small. More research is needed to evaluate the importance of nitrogen transfer within leaf and bract cells of plants.
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Affiliation(s)
- April Micci
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
- Correspondence: (A.M.); (J.F.W.); Tel.: +848-932-6286 (J.F.W.)
| | - Qiuwei Zhang
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Xiaoqian Chang
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Kathryn Kingsley
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Linsey Park
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Peerapol Chiaranunt
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Raquele Strickland
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Fernando Velazquez
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Sean Lindert
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Matthew Elmore
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Philip L. Vines
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
| | - Sharron Crane
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA;
| | - Ivelisse Irizarry
- School of Health and Sciences, Universidad del Sagrado Corazón, San Juan 00914, Puerto Rico;
| | - Kurt P. Kowalski
- US Geological Survey Great Lakes Science Center, Ann Arbor, MI 48105, USA;
| | - David Johnston-Monje
- Max Planck Tandem Group in Plant Microbial Ecology, Universidad del Valle, Cali 760043, Colombia;
| | - James F. White
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA; (Q.Z.); (X.C.); (K.K.); (L.P.); (P.C.); (R.S.); (F.V.); (S.L.); (M.E.); (P.L.V.)
- Correspondence: (A.M.); (J.F.W.); Tel.: +848-932-6286 (J.F.W.)
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Zheng F, Mou X, Zhang J, Zhang T, Xia L, Yin S, Wu L, Leng X, An S, Zhao D. Gradual Enhancement of the Assemblage Stability of the Reed Rhizosphere Microbiome with Recovery Time. Microorganisms 2022; 10:microorganisms10050937. [PMID: 35630381 PMCID: PMC9146439 DOI: 10.3390/microorganisms10050937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/21/2022] [Accepted: 04/27/2022] [Indexed: 12/04/2022] Open
Abstract
Rhizoplane microbes are considered proxies for evaluating the assemblage stability of the rhizosphere in wetland ecosystems due to their roles in plant growth and ecosystem health. However, our knowledge of how microbial assemblage stability is promoted in the reed rhizosphere of wetlands undergoing recovery is limited. We investigated the assemblage stability, diversity, abundance, co-occurrence patterns, and functional characteristics of reed rhizosphere microbes in restored wetlands. The results indicated that assemblage stability significantly increased with recovery time and that the microbial assemblages were capable of resisting seasonal fluctuations after more than 20 years of restoration. The number of bacterial indicators was greater in the restoration groups with longer restoration periods. Most bacterial indicators appeared in the 30-year restoration group. However, the core taxa and keystone species of module 2 exhibited greater abundance within longer recovery periods and were well organized, with rich and diverse functions that enhanced microbial assemblage stability. Our study provides insight into the connection between the rhizosphere microbiome and recovery period and presents a useful theoretical basis for the empirical management of wetland ecosystems.
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Affiliation(s)
- Fuchao Zheng
- Institute of Wetland Ecology, School of Life Science, Nanjing University, Nanjing 210023, China; (F.Z.); (X.M.); (J.Z.); (T.Z.); (L.X.); (X.L.)
| | - Xiaoming Mou
- Institute of Wetland Ecology, School of Life Science, Nanjing University, Nanjing 210023, China; (F.Z.); (X.M.); (J.Z.); (T.Z.); (L.X.); (X.L.)
| | - Jinghua Zhang
- Institute of Wetland Ecology, School of Life Science, Nanjing University, Nanjing 210023, China; (F.Z.); (X.M.); (J.Z.); (T.Z.); (L.X.); (X.L.)
| | - Tiange Zhang
- Institute of Wetland Ecology, School of Life Science, Nanjing University, Nanjing 210023, China; (F.Z.); (X.M.); (J.Z.); (T.Z.); (L.X.); (X.L.)
| | - Lu Xia
- Institute of Wetland Ecology, School of Life Science, Nanjing University, Nanjing 210023, China; (F.Z.); (X.M.); (J.Z.); (T.Z.); (L.X.); (X.L.)
| | - Shenglai Yin
- College of Life Sciences, Nanjing Normal University, Nanjing 210023, China;
| | - Lingye Wu
- Changshu Wetland Conservation and Management Station, Changshu 215500, China;
| | - Xin Leng
- Institute of Wetland Ecology, School of Life Science, Nanjing University, Nanjing 210023, China; (F.Z.); (X.M.); (J.Z.); (T.Z.); (L.X.); (X.L.)
| | - Shuqing An
- Institute of Wetland Ecology, School of Life Science, Nanjing University, Nanjing 210023, China; (F.Z.); (X.M.); (J.Z.); (T.Z.); (L.X.); (X.L.)
- Nanjing University Ecology Research Institute of Changshu, Changshu 215500, China
- Correspondence: (S.A.); (D.Z.)
| | - Dehua Zhao
- Institute of Wetland Ecology, School of Life Science, Nanjing University, Nanjing 210023, China; (F.Z.); (X.M.); (J.Z.); (T.Z.); (L.X.); (X.L.)
- Correspondence: (S.A.); (D.Z.)
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Hernández-Guzmán M, Pérez-Hernández V, Navarro-Noya YE, Luna-Guido ML, Verhulst N, Govaerts B, Dendooven L. Application of ammonium to a N limited arable soil enriches a succession of bacteria typically found in the rhizosphere. Sci Rep 2022; 12:4110. [PMID: 35260645 PMCID: PMC8904580 DOI: 10.1038/s41598-022-07623-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 02/01/2022] [Indexed: 12/30/2022] Open
Abstract
Crop residue management and tillage are known to affect the soil bacterial community, but when and which bacterial groups are enriched by application of ammonium in soil under different agricultural practices from a semi-arid ecosystem is still poorly understood. Soil was sampled from a long-term agronomic experiment with conventional tilled beds and crop residue retention (CT treatment), permanent beds with crop residue burned (PBB treatment) or retained (PBC) left unfertilized or fertilized with 300 kg urea-N ha−1 and cultivated with wheat (Triticum durum L.)/maize (Zea mays L.) rotation. Soil samples, fertilized or unfertilized, were amended or not (control) with a solution of (NH4)2SO4 (300 kg N ha−1) and were incubated aerobically at 25 ± 2 °C for 56 days, while CO2 emission, mineral N and the bacterial community were monitored. Application of NH4+ significantly increased the C mineralization independent of tillage-residue management or N fertilizer. Oxidation of NH4+ and NO2− was faster in the fertilized soil than in the unfertilized soil. The relative abundance of Nitrosovibrio, the sole ammonium oxidizer detected, was higher in the fertilized than in the unfertilized soil; and similarly, that of Nitrospira, the sole nitrite oxidizer. Application of NH4+ enriched Pseudomonas, Flavisolibacter, Enterobacter and Pseudoxanthomonas in the first week and Rheinheimera, Acinetobacter and Achromobacter between day 7 and 28. The application of ammonium to a soil cultivated with wheat and maize enriched a sequence of bacterial genera characterized as rhizospheric and/or endophytic independent of the application of urea, retention or burning of the crop residue, or tillage.
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Affiliation(s)
- Mario Hernández-Guzmán
- Laboratory of Soil Ecology, CINVESTAV, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Alcaldía Gustavo A Madero, Mexico City, Mexico
| | - Valentín Pérez-Hernández
- Laboratory of Soil Ecology, CINVESTAV, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Alcaldía Gustavo A Madero, Mexico City, Mexico.,Department of Chemistry and Biochemistry, Instituto Tecnológico de Tuxtla-Gutiérrez, Tuxtla Gutiérrez, Mexico
| | - Yendi E Navarro-Noya
- Centro de Investigación en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, Tlaxcala, México
| | - Marco L Luna-Guido
- Laboratory of Soil Ecology, CINVESTAV, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Alcaldía Gustavo A Madero, Mexico City, Mexico
| | - Nele Verhulst
- International Maize and Wheat Improvement Center (CIMMYT), El Batán, Texcoco, Mexico
| | - Bram Govaerts
- International Maize and Wheat Improvement Center (CIMMYT), El Batán, Texcoco, Mexico.,Cornell University, Ithaca, USA
| | - Luc Dendooven
- Laboratory of Soil Ecology, CINVESTAV, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, Alcaldía Gustavo A Madero, Mexico City, Mexico.
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Aiysha D, Latif Z. Assessing hydrolytic enzyme production ability of bacterial strains from bovine manure as potential biowaste conversion candidates. J Basic Microbiol 2021; 62:116-123. [DOI: 10.1002/jobm.202100294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 10/10/2021] [Accepted: 11/20/2021] [Indexed: 11/10/2022]
Affiliation(s)
- Dalaq Aiysha
- Institute of Microbiology and Molecular Genetics, Faculty of Life Sciences, Quaid‐i‐Azam Campus University of the Punjab Lahore Pakistan
| | - Zakia Latif
- Institute of Microbiology and Molecular Genetics, Faculty of Life Sciences, Quaid‐i‐Azam Campus University of the Punjab Lahore Pakistan
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10
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He R, Zeng J, Zhao D, Wang S, Wu QL. Decreased spatial variation and deterministic processes of bacterial community assembly in the rhizosphere of Phragmites australis across the Middle-Lower Yangtze plain. Mol Ecol 2021; 31:1180-1195. [PMID: 34846091 DOI: 10.1111/mec.16298] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/31/2021] [Accepted: 11/22/2021] [Indexed: 12/13/2022]
Abstract
Comparison of the spatial distribution and assembly processes between bulk and rhizosphere bacterial communities at multiple spatial scales is vital for understanding the generation and maintenance of microbial diversity under the influence of plants. However, biogeographical patterns and the underlying mechanisms of microbial communities in bulk and rhizosphere sediments of aquatic ecosystems remain unclear. Here, we collected 140 bulk and rhizosphere sediment samples of Phragmites australis from 14 lakeshore zones across a 510-km transect in the Middle-Lower Yangtze plain. We performed high-throughput sequencing to investigate the bacterial diversity, composition, spatial distribution and assembly processes of these samples. Bacterial communities in the rhizosphere sediment exhibited higher alpha diversity but lower beta diversity than those in the bulk sediment. Both bulk and rhizosphere sediment bacterial communities had significant distance-decay relationships, but spatial turnover of the rhizosphere sediment bacterial community was strikingly lower than that of bulk sediment. Despite variable selection dominating the assembly processes of bacterial communities in bulk sediment, the rhizosphere of P. australis enhanced the role of dispersal limitation in governing bacterial communities. The relative importance of different ecological processes in determining bacterial assembly presented distinct patterns of increasing or decreasing linearly with an increase of scale. This investigation highlights the convergent selection of the aquatic plant rhizosphere for surrounding bacterial communities and emphasizes the importance of different ecological processes on bacterial community assembly in sediment environments over different scales. Furthermore, we provide a preliminary framework for exploring the scale dependence of microbial community assembly in aquatic ecosystems.
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Affiliation(s)
- Rujia He
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.,Joint International Research Laboratory of Global Change and Water Cycle, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China
| | - Jin Zeng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Dayong Zhao
- Joint International Research Laboratory of Global Change and Water Cycle, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China
| | - Shuren Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.,Joint International Research Laboratory of Global Change and Water Cycle, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China
| | - Qinglong L Wu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.,Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing, China
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11
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Complete Genome Sequence of Achromobacter Strain ES-001, a Betaproteobacterium Associated with a Cellulolytic Soil Community. Microbiol Resour Announc 2021; 10:e0082821. [PMID: 34617787 PMCID: PMC8496361 DOI: 10.1128/mra.00828-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome sequence of the soilborne bacterium Achromobacter strain ES-001, assembled from Illumina NextSeq and Nanopore MinION reads, is rich in genes predicted to encode iron, arsenic, and hydrocarbon metabolism, as well as type 6 secretion components. The sequenced genome will aid in determining the roles of noncellulolytic species in cellulose-enriched environments.
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Naik B, Goyal SK, Tripathi AD, Kumar V. Exploring the diversity of endophytic fungi and screening for their pullulanase-producing capabilities. J Genet Eng Biotechnol 2021; 19:110. [PMID: 34324093 PMCID: PMC8322383 DOI: 10.1186/s43141-021-00208-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/09/2021] [Indexed: 11/10/2022]
Abstract
Background Pullulanases are the significant industrial group in the 13 glycosyl hydrolases category, known as the α-amylases family. There are very few reports on pullulanase from fungal sources. Based on the above research gap, the present study was undertaken to explore the endophytic fungi for their pullulanase-producing capabilities. Results A total of 126 endophytes were isolated from Tradescantia pallida, Zea mays, and Trifolium alexandrinum. Aspergillus, Penicillium, and Ganoderma species recovered highest from the stem of Tradescantia palida. Fusarium was dominant in the stem and leaf of Zea mays. Penicillium, Aspergillus, Ganoderma, Cladosporium, Fusarium, and Alternaria were recovered from the Trifolium alexandrium. The Shannon index in Tradescantia pallida was highest in leaves while in Zea mays and Trifolium alexandrinum, it is highest in the stem. The Simpson’s index is highest in the case of Zea mays stem and root. Species richness was indicated by Menhinick’s index, and it was found that this value was highest in the roots of Trifolium alexandrinum. As per our knowledge, no comparative data is available on the endophytic diversity of the above plants taken for the study. Out of 126 endophytes, only 2.38% produced pullulanase while 7.94% produced amylase. The recovery of pullulanase-producing endophytic fungi was very less. But the importance of pullulanase is high as compared to amylase because it has both α-1,6 and α-1,4 hydrolyzing ability. Therefore, the most promising isolates were identified by ITS sequence analysis. Based on spore chain morphology, isolates BHU-25 and BHU-30 were identified as Penicillium sp. and Aspergillus species, respectively. This is the first report of pullulanase from endophytic Aspergillus and Penicillium. Conclusion Endophytes Aspergillus sp. and Penicillium sp. produce pullulanase enzyme. This is the first report of pullulanase from endophytic Aspergillus and Penicillium. Supplementary Information The online version contains supplementary material available at 10.1186/s43141-021-00208-0.
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Affiliation(s)
- Bindu Naik
- Department of Agricultural Engineering (Formely Farm Engineering), Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, UP, 221005, India
| | - S K Goyal
- Department of Agricultural Engineering (Formely Farm Engineering), Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, UP, 221005, India
| | - Abhishek Dutt Tripathi
- Centre of Food Science and Technology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, UP, 221005, India
| | - Vijay Kumar
- Department of Biosciences, Swami Rama Himalayan University, Swami Rama Nagar, Jolly grant, Dehradun, Uttarakhand, 248140, India.
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13
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Invasive Lactuca serriola seeds contain endophytic bacteria that contribute to drought tolerance. Sci Rep 2021; 11:13307. [PMID: 34172799 PMCID: PMC8233371 DOI: 10.1038/s41598-021-92706-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 06/15/2021] [Indexed: 02/06/2023] Open
Abstract
The mutualistic relationship between alien plant species and microorganisms is proposed to facilitate or hinder invasive success, depending on whether plants can form novel associations with microorganisms in the introduced habitats. However, this hypothesis has not considered seed endophytes that would move together with plant propagules. Little information is available on the seed endophytic bacteria of invasive species and their effects on plant performance. We isolated the seed endophytic bacteria of a xerophytic invasive plant, Lactuca serriola, and examined their plant growth-promoting traits. In addition, we assessed whether these seed endophytes contributed to plant drought tolerance. Forty-two bacterial species were isolated from seeds, and all of them exhibited at least one plant growth-promoting trait. Kosakonia cowanii occurred in all four tested plant populations and produced a high concentration of exopolysaccharides in media with a highly negative water potential. Notably, applying K. cowanii GG1 to Arabidopsis thaliana stimulated plant growth under drought conditions. It also reduced soil water loss under drought conditions, suggesting bacterial production of exopolysaccharides might contribute to the maintenance of soil water content. These results imply that invasive plants can disperse along with beneficial bacterial symbionts, which potentially improve plant fitness and help to establish alien plant species.
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14
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Verma SK, Sahu PK, Kumar K, Pal G, Gond SK, Kharwar RN, White JF. Endophyte roles in nutrient acquisition, root system architecture development and oxidative stress tolerance. J Appl Microbiol 2021; 131:2161-2177. [PMID: 33893707 DOI: 10.1111/jam.15111] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/06/2021] [Accepted: 04/16/2021] [Indexed: 01/01/2023]
Abstract
Plants associate with communities of microbes (bacteria and fungi) that play critical roles in plant development, nutrient acquisition and oxidative stress tolerance. The major share of plant microbiota is endophytes which inhabit plant tissues and help them in various capacities. In this article, we have reviewed what is presently known with regard to how endophytic microbes interact with plants to modulate root development, branching, root hair formation and their implications in overall plant development. Endophytic microbes link the interactions of plants, rhizospheric microbes and soil to promote nutrient solubilization and further vectoring these nutrients to the plant roots making the soil-plant-microbe continuum. Further, plant roots internalize microbes and oxidatively extract nutrients from microbes in the rhizophagy cycle. The oxidative interactions between endophytes and plants result in the acquisition of nutrients by plants and are also instrumental in oxidative stress tolerance of plants. It is evident that plants actively cultivate microbes internally, on surfaces and in soils to acquire nutrients, modulate development and improve health. Understanding this continuum could be of greater significance in connecting endophytes with the hidden half of the plant that can also be harnessed in applied terms to enhance nutrient acquisition through the development of favourable root system architecture for sustainable production under stress conditions.
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Affiliation(s)
- S K Verma
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - P K Sahu
- National Bureau of Agriculturally Important Microorganism, Mau, Uttar Pradesh, India
| | - K Kumar
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - G Pal
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - S K Gond
- Botany Section, MMV, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - R N Kharwar
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - J F White
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA
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15
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Mello IS, Targanski S, Pietro-Souza W, Frutuoso Stachack FF, Terezo AJ, Soares MA. Endophytic bacteria stimulate mercury phytoremediation by modulating its bioaccumulation and volatilization. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 202:110818. [PMID: 32590206 DOI: 10.1016/j.ecoenv.2020.110818] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/24/2020] [Accepted: 05/25/2020] [Indexed: 05/27/2023]
Abstract
The quantification, efficiency, and possible mechanisms of mercury phytoremediation by endophytic bacteria are poorly understood. Here we selected 8 out of 34 previously isolated endophytic bacterial strains with a broad resistance profile to metals and 11 antibiotics: Acinetobacter baumannii BacI43, Bacillus sp. BacI34, Enterobacter sp. BacI14, Klebsiella pneumoniae BacI20, Pantoea sp. BacI23, Pseudomonas sp. BacI7, Pseudomonas sp. BacI38, and Serratia marcescens BacI56. Except for Klebsiella pneumoniae BacI20, the other seven bacterial strains promoted maize growth on a mercury-contaminated substrate. Acinetobacter baumannii BacI43 and Bacillus sp. BacI34 increased total dry biomass by approximately 47%. The bacteria assisted mercury remediation by decreasing the metal amount in the substrate, possibly by promoting its volatilization. The plants inoculated with Serratia marcescens BacI56 and Pseudomonas sp. BacI38 increased mercury volatilization to 47.16% and 62.42%, respectively. Except for Bacillus sp. BacI34 and Pantoea sp. BacI23, the other six bacterial strains favored mercury bioaccumulation in plant tissues. Endophytic bacteria-assisted phytoremediation contributed to reduce the substrate toxicity assessed in different model organisms. The endophytic bacterial strains selected herein are potential candidates for assisted phytoremediation that shall help reduce environmental toxicity of mercury-contaminated soils.
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Affiliation(s)
- Ivani Souza Mello
- Laboratório de Biotecnologia e Ecologia Microbiana, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Sabrina Targanski
- Laboratório de Biotecnologia e Ecologia Microbiana, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - William Pietro-Souza
- Instituto Federal de Educação, Ciência e Tecnologia de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | | | - Ailton Jose Terezo
- Central Analítica de Combustíveis, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Marcos Antônio Soares
- Laboratório de Biotecnologia e Ecologia Microbiana, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil.
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16
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Contrasting Patterns in Diversity and Community Assembly of Phragmites australis Root-Associated Bacterial Communities from Different Seasons. Appl Environ Microbiol 2020; 86:AEM.00379-20. [PMID: 32385080 DOI: 10.1128/aem.00379-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/01/2020] [Indexed: 12/13/2022] Open
Abstract
The common reed (Phragmites australis), a cosmopolitan aquatic macrophyte, plays an important role in the structure and function of aquatic ecosystems. We compared bacterial community compositions (BCCs) and their assembly processes in the root-associated compartments (i.e., rhizosphere and endosphere) of reed and bulk sediment between summer and winter. The BCCs were analyzed using high-throughput sequencing of the bacterial 16S rRNA gene; meanwhile, null-model analysis was employed to characterize their assembly mechanisms. The sources of the endosphere BCCs were quantitatively examined using SourceTracker from bulk sediment, rhizosphere, and seed. We observed the highest α-diversity and the lowest β-diversity of BCCs in the rhizosphere in both seasons. We also found a significant increase in α- and β-diversity in summer compared to that in winter among the three compartments. It was demonstrated that rhizosphere sediments were the main source (∼70%) of root endosphere bacteria during both seasons. Null-model tests indicated that stochastic processes primarily affected endosphere BCCs, whereas both deterministic and stochastic processes dictated bacterial assemblages of the rhizosphere, with the relative importance of stochastic versus deterministic processes depending on the season. This study suggests that multiple mechanisms of bacterial selection and community assembly exist both inside and outside P. australis roots in different seasons.IMPORTANCE Understanding the composition and assembly mechanisms of root-associated microbial communities of plants is crucial for understanding the interactions between plants and soil. Most previous studies of the plant root-associated microbiome focused on model and economic plants, with fewer temporal or seasonal investigations. The assembly mechanisms of root-associated bacterial communities in different seasons remain poorly known, especially for the aquatic macrophytes. In this study, we compared the diversity, composition, and relative importance of two different assembly processes (stochastic and deterministic processes) of bacterial communities associated with bulk sediment and the rhizosphere and endosphere of Phragmites australis in summer and winter. While we found apparent differences in composition, diversity, and assembly processes of bacterial communities among different compartments, season played important roles in determining BCCs and their diversity patterns and assemblages. We also found that endosphere bacteria mainly originated from the rhizosphere. The results add new knowledge regarding the plant-microbe interactions in aquatic ecosystems.
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17
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18
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19
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White JF, Kingsley KL, Verma SK, Kowalski KP. Rhizophagy Cycle: An Oxidative Process in Plants for Nutrient Extraction from Symbiotic Microbes. Microorganisms 2018; 6:microorganisms6030095. [PMID: 30227634 PMCID: PMC6164190 DOI: 10.3390/microorganisms6030095] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 09/01/2018] [Accepted: 09/05/2018] [Indexed: 12/20/2022] Open
Abstract
In this paper, we describe a mechanism for the transfer of nutrients from symbiotic microbes (bacteria and fungi) to host plant roots that we term the ‘rhizophagy cycle.’ In the rhizophagy cycle, microbes alternate between a root intracellular endophytic phase and a free-living soil phase. Microbes acquire soil nutrients in the free-living soil phase; nutrients are extracted through exposure to host-produced reactive oxygen in the intracellular endophytic phase. We conducted experiments on several seed-vectored microbes in several host species. We found that initially the symbiotic microbes grow on the rhizoplane in the exudate zone adjacent the root meristem. Microbes enter root tip meristem cells—locating within the periplasmic spaces between cell wall and plasma membrane. In the periplasmic spaces of root cells, microbes convert to wall-less protoplast forms. As root cells mature, microbes continue to be subjected to reactive oxygen (superoxide) produced by NADPH oxidases (NOX) on the root cell plasma membranes. Reactive oxygen degrades some of the intracellular microbes, also likely inducing electrolyte leakage from microbes—effectively extracting nutrients from microbes. Surviving bacteria in root epidermal cells trigger root hair elongation and as hairs elongate bacteria exit at the hair tips, reforming cell walls and cell shapes as microbes emerge into the rhizosphere where they may obtain additional nutrients. Precisely what nutrients are transferred through rhizophagy or how important this process is for nutrient acquisition is still unknown.
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Affiliation(s)
- James F White
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA.
| | - Kathryn L Kingsley
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA.
| | - Satish K Verma
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, UP 221005, India.
| | - Kurt P Kowalski
- U.S. Geological Survey, Great Lakes Science Center, 1451 Green Road, Ann Arbor, MI 48105-2807, USA.
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20
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Mathai PP, Dunn HM, Magnone P, Brown CM, Chun CL, Sadowsky MJ. Spatial and temporal characterization of epiphytic microbial communities associated with Eurasian watermilfoil: a highly invasive macrophyte in North America. FEMS Microbiol Ecol 2018; 94:5089967. [DOI: 10.1093/femsec/fiy178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 09/01/2018] [Indexed: 01/19/2023] Open
Affiliation(s)
- Prince P Mathai
- BioTechnology Institute, University of Minnesota, 140 Gortner Laboratory, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Hannah M Dunn
- BioTechnology Institute, University of Minnesota, 140 Gortner Laboratory, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Paolo Magnone
- BioTechnology Institute, University of Minnesota, 140 Gortner Laboratory, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Clairessa M Brown
- BioTechnology Institute, University of Minnesota, 140 Gortner Laboratory, 1479 Gortner Ave, St. Paul, MN 55108, USA
| | - Chan Lan Chun
- Department of Civil Engineering, University of Minnesota, 1405 University Drive, Duluth, MN 55812, USA
- National Resources Research Institute, University of Minnesota, 5013 Miller Trunk Highway, Duluth, MN 55811, USA
| | - Michael J Sadowsky
- BioTechnology Institute, University of Minnesota, 140 Gortner Laboratory, 1479 Gortner Ave, St. Paul, MN 55108, USA
- Department of Soil, Water, and Climate, University of Minnesota, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA
- Department of Plant and Microbial Biology, University of Minnesota, 140 Gortner Laboratory, 1479 Gortner Ave, St. Paul, MN 55108, USA
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21
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Verma SK, White JF. Indigenous endophytic seed bacteria promote seedling development and defend against fungal disease in browntop millet (Urochloa ramosa L.). J Appl Microbiol 2018; 124:764-778. [PMID: 29253319 DOI: 10.1111/jam.13673] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/22/2017] [Accepted: 12/11/2017] [Indexed: 11/29/2022]
Abstract
AIMS This study was conducted to investigate indigenous seed endophyte effects on browntop millet seedling development. We report that seed-inhabiting bacterial endophytes are responsible for promoting seedling development, including stimulation of root hair formation, increasing root and shoot length growth and increasing photosynthetic pigment content of seedlings. Bacterial endophytes also improved resistance of seedlings to disease. METHODS AND RESULTS A total of four endophytic bacteria were isolated from surface-sterilized seeds and identified by 16S rDNA sequencing as Curtobacterium sp. (M1), Microbacterium sp. (M2), Methylobacterium sp. (M3) and Bacillus amyloliquefaciens (M4). Removal of bacteria with streptomycin treatment from the seeds compromised seedling growth and development. When endophytes were reinoculated onto seeds, seedlings recovered normal development. Strains M3 and M4 were found to be most potent in promoting growth of seedlings. Bacteria were found to produce auxin, solubilize phosphate and inhibit fungal pathogens. Significant protection of seedlings from Fusarium infection was found using strain M4 in microcosm assays. The antifungal lipopeptide genes for surfactin and iturin were detected in M4; culture extracts of M4 showed a positive drop collapse result for surfactins. CONCLUSIONS This study demonstrates that browntop millet seeds vector indigenous endophytes that are responsible for modulation of seedling development and protection of seedlings from fungal disease. SIGNIFICANCE AND IMPACT OF THE STUDY This study is significant and original in that it is the first report of seed-inhabiting endophytes of browntop millet that influence seedling development and function in defence against soilborne pathogens. This study suggests that conservation and management of seed-vectored endophytes may be important in development of more sustainable agricultural practices.
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Affiliation(s)
- S K Verma
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA.,Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - J F White
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA
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22
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Multifunctional potential of endophytic and rhizospheric microbial isolates associated with Butia purpurascens roots for promoting plant growth. Antonie van Leeuwenhoek 2018; 111:2157-2174. [DOI: 10.1007/s10482-018-1108-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/24/2018] [Indexed: 01/29/2023]
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Diversity of cultivable fungal endophytes in Paullinia cupana (Mart.) Ducke and bioactivity of their secondary metabolites. PLoS One 2018; 13:e0195874. [PMID: 29649297 PMCID: PMC5897019 DOI: 10.1371/journal.pone.0195874] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 03/30/2018] [Indexed: 11/19/2022] Open
Abstract
Paullinia cupana is associated with a diverse community of pathogenic and endophytic microorganisms. We isolated and identified endophytic fungal communities from the roots and seeds of P. cupana genotypes susceptible and tolerant to anthracnose that grow in two sites of the Brazilian Amazonia forest. We assessed the antibacterial, antitumor and genotoxic activity in vitro of compounds isolated from the strains Trichoderma asperellum (1BDA) and Diaporthe phaseolorum (8S). In concert, we identified eight fungal species not previously reported as endophytes; some fungal species capable of inhibiting pathogen growth; and the production of antibiotics and compounds with bacteriostatic activity against Pseudomonas aeruginosa in both susceptible and multiresistant host strains. The plant genotype, geographic location and specially the organ influenced the composition of P. cupana endophytic fungal community. Together, our findings identify important functional roles of endophytic species found within the microbiome of P. cupana. This hypothesis requires experimental validation to propose management of this microbiome with the objective of promoting plant growth and protection.
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24
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Verma SK, Kingsley K, Irizarry I, Bergen M, Kharwar RN, White JF. Seed-vectored endophytic bacteria modulate development of rice seedlings. J Appl Microbiol 2017; 122:1680-1691. [PMID: 28375579 DOI: 10.1111/jam.13463] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 03/26/2017] [Accepted: 03/28/2017] [Indexed: 11/30/2022]
Abstract
AIM The aim of the present study was to evaluate the effects of the removal of indigenous bacteria from rice seeds on seedling growth and development. Here we report the presence of three indigenous endophytic bacteria in rice seeds that play important roles in modulating seedling development (shoot and root lengths, and formation of root hairs and secondary roots) and defence against pathogens. METHODS AND RESULTS Seed-associated bacteria were removed using surface sterilization with NaOCl (bleach) followed by antibiotic treatment. When bacteria were absent, growth of seedlings in terms of root hair development and overall seedling size was less than that of seedlings that contained bacteria. Reactive oxygen staining of seedlings showed that endophytic bacteria became intracellular in root parenchyma cells and root hairs. Roots containing endophytic bacteria were seen to stain densely for reactive oxygen, while roots free of bacteria stained lightly for reactive oxygen. Bacteria were isolated and identified as Enterobacter asburiae (VWB1), Pantoea dispersa (VWB2) and Pseudomonas putida (VWB3) by 16S rDNA sequencing. Bacteria were found to produce indole acetic acid (auxins), inhibited the pathogen Fusarium oxysporum and solubilized phosphate. Reinoculation of bacteria onto seedlings derived from surface-disinfected rice and Bermuda grass seeds significantly restored seedling growth and development. CONCLUSION Rice seeds harbour indigenous bacterial endophytes that greatly influence seedling growth and development, including root and shoot lengths, root hair formation and disease susceptibility of rice seedlings. SIGNIFICANCE AND IMPACT OF THE STUDY This study shows that seeds of rice naturally harbour bacterial endophytes that play key roles in modulation of seedling development.
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Affiliation(s)
- S K Verma
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA.,Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, UP, India
| | - K Kingsley
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA
| | - I Irizarry
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA
| | - M Bergen
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA
| | - R N Kharwar
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, UP, India
| | - J F White
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA
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Thomas P, Sekhar AC. Cultivation Versus Molecular Analysis of Banana (Musa sp.) Shoot-Tip Tissue Reveals Enormous Diversity of Normally Uncultivable Endophytic Bacteria. MICROBIAL ECOLOGY 2017; 73:885-899. [PMID: 27833995 DOI: 10.1007/s00248-016-0877-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/10/2016] [Indexed: 05/06/2023]
Abstract
The interior of plants constitutes a unique environment for microorganisms with various organisms inhabiting as endophytes. Unlike subterranean plant parts, aboveground parts are relatively less explored for endophytic microbial diversity. We employed a combination of cultivation and molecular approaches to study the endophytic bacterial diversity in banana shoot-tips. Cultivable bacteria from 20 sucker shoot-tips of cv. Grand Naine included 37 strains under 16 genera and three phyla (Proteobacteria, Actinobacteria, Firmicutes). 16S rRNA gene-ribotyping approach on 799f and 1492r PCR-amplicons to avoid plant organelle sequences was ineffective showing limited bacterial diversity. 16S rRNA metagene profiling targeting the V3-V4 hypervariable region after filtering out the chloroplast (74.2 %), mitochondrial (22.9 %), and unknown sequences (1.1 %) revealed enormous bacterial diversity. Proteobacteria formed the predominant phylum (64 %) succeeded by Firmicutes (12.1 %), Actinobacteria (9.5 %), Bacteroidetes (6.4 %), Planctomycetes, Cyanobacteria, and minor shares (<1 %) of 14 phyla including several candidate phyla besides the domain Euryarchaeota (0.2 %). Microbiome analysis of single shoot-tips through 16S rRNA V3 region profiling showed similar taxonomic richness and diversity and was less affected by plant sequence interferences. DNA extraction kit ominously influenced the phylogenetic diversity. The study has revealed vast diversity of normally uncultivable endophytic bacteria prevailing in banana shoot-tips (20 phyla, 46 classes) with about 2.6 % of the deciphered 269 genera and 1.5 % of the 656 observed species from the same source of shoot-tips attained through cultivation. The predominant genera included several agriculturally important bacteria. The study reveals an immense ecosystem of endophytic bacteria in banana shoot tissues endorsing the earlier documentation of intracellular "Cytobacts" and "Peribacts" with possible roles in plant holobiome and hologenome.
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Affiliation(s)
- Pious Thomas
- Endophytic and Molecular Microbiology Laboratory, Division of Biotechnology, ICAR-Indian Institute of Horticultural Research (IIHR), Hessaraghatta Lake, Bengaluru, 560089, India.
| | - Aparna Chandra Sekhar
- Endophytic and Molecular Microbiology Laboratory, Division of Biotechnology, ICAR-Indian Institute of Horticultural Research (IIHR), Hessaraghatta Lake, Bengaluru, 560089, India
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