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Liu X, Lertsethtakarn P, Mariscal VT, Yildiz F, Ottemann KM. Counterclockwise rotation of the flagellum promotes biofilm initiation in Helicobacter pylori. mBio 2024:e0044024. [PMID: 38700325 DOI: 10.1128/mbio.00440-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/26/2024] [Indexed: 05/05/2024] Open
Abstract
Motility promotes biofilm initiation during the early steps of this process: microbial surface association and attachment. Motility is controlled in part by chemotaxis signaling, so it seems reasonable that chemotaxis may also affect biofilm formation. There is a gap, however, in our understanding of the interactions between chemotaxis and biofilm formation, partly because most studies analyzed the phenotype of only a single chemotaxis signaling mutant, e.g., cheA. Here, we addressed the role of chemotaxis in biofilm formation using a full set of chemotaxis signaling mutants in Helicobacter pylori, a class I carcinogen that infects more than half the world's population and forms biofilms. Using mutants that lack each chemotaxis signaling protein, we found that chemotaxis signaling affected the biofilm initiation stage, but not mature biofilm formation. Surprisingly, some chemotaxis mutants elevated biofilm initiation, while others inhibited it in a manner that was not tied to chemotaxis ability or ligand input. Instead, the biofilm phenotype correlated with flagellar rotational bias. Specifically, mutants with a counterclockwise bias promoted biofilm initiation, e.g., ∆cheA, ∆cheW, or ∆cheV1; in contrast, those with a clockwise bias inhibited it, e.g., ∆cheZ, ∆chePep, or ∆cheV3. We tested this correlation using a counterclockwise bias-locked flagellum, which induced biofilm formation independent of the chemotaxis system. These CCW flagella, however, were not sufficient to induce biofilm formation, suggesting there are downstream players. Overall, our work highlights the new finding that flagellar rotational direction promotes biofilm initiation, with the chemotaxis signaling system operating as one mechanism to control flagellar rotation. IMPORTANCE Chemotaxis signaling systems have been reported to contribute to biofilm formation in many bacteria; however, how they regulate biofilm formation remains largely unknown. Chemotaxis systems are composed of many distinct kinds of proteins, but most previous work analyzed the biofilm effect of loss of only a few. Here, we explored chemotaxis' role during biofilm formation in the human-associated pathogenic bacterium Helicobacter pylori. We found that chemotaxis proteins are involved in biofilm initiation in a manner that correlated with how they affected flagellar rotation. Biofilm initiation was high in mutants with counterclockwise (CCW) flagellar bias and low in those with clockwise bias. We supported the idea that a major driver of biofilm formation is flagellar rotational direction using a CCW-locked flagellar mutant, which stays CCW independent of chemotaxis input and showed elevated biofilm initiation. Our data suggest that CCW-rotating flagella, independent of chemotaxis inputs, are a biofilm-promoting signal.
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Affiliation(s)
- Xiaolin Liu
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
| | - Paphavee Lertsethtakarn
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
| | - Vanessa T Mariscal
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
| | - Fitnat Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
| | - Karen M Ottemann
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA
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2
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Zhang B, Zhang J, Wang Y, Qu J, Jiang Z, Zhang X, Tao Y, Wang Y, Kang Z, Han S, Zhang J, Zhang Y. Biodegradation of atrazine with biochar-mediated functional bacterial biofilm: Construction, characterization and mechanisms. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133237. [PMID: 38113741 DOI: 10.1016/j.jhazmat.2023.133237] [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: 09/20/2023] [Revised: 11/05/2023] [Accepted: 12/10/2023] [Indexed: 12/21/2023]
Abstract
The abuse and residue of herbicides in the black soil area had seriously affected the soil structure, function and crop growth, posing severe threats to agricultural soil environment and public health. Given the limitation of routine microbial remediation, innovative and eco-friendly functional bacterial biofilm which could adapt under adverse conditions was developed on the biochar to investigate its enhanced bioremediation and metabolic characteristics of typical herbicide atrazine. Results revealed that the atrazine degrading strain Acinetobacter lwoffii had competitive advantage in soil indigenous microorganisms and formed dense biofilms on the biochar which was beneficial to cell viability maintenance and aggregations. Metatranscriptomics and RT-qPCR analysis demonstrated that the biochar-mediated biofilm improved the frequency of intercellular communications through quorum sensing and two-component signal regulation systems, and enhanced the atrazine biodegradation efficiency through horizontal gene transfer in co-metabolism mode, providing important scientific basis for the biological remediation of farmland soil non-point source pollution.
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Affiliation(s)
- Bo Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Jingdan Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Yuping Wang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Jianhua Qu
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Zhao Jiang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Xu Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Yue Tao
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Yifan Wang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Zhonghui Kang
- Longjiang Environmental Protection Group Co.,Ltd., Harbin 150050, PR China
| | - Songting Han
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Jingyi Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Ying Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China.
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3
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Li Y, Narayanan M, Shi X, Chen X, Li Z, Ma Y. Biofilms formation in plant growth-promoting bacteria for alleviating agro-environmental stress. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167774. [PMID: 37848152 DOI: 10.1016/j.scitotenv.2023.167774] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/02/2023] [Accepted: 10/10/2023] [Indexed: 10/19/2023]
Abstract
Biofilm formation represents a pivotal and adaptable trait among microorganisms within natural environments. This attribute plays a multifaceted role across diverse contexts, including environmental, aquatic, industrial, and medical systems. While previous research has primarily focused on the adverse impacts of biofilms, harnessing their potential effectively could confer substantial advantages to humanity. In the face of escalating environmental pressures (e.g., drought, salinity, extreme temperatures, and heavy metal pollution), which jeopardize global crop yields, enhancing crop stress tolerance becomes a paramount endeavor for restoring sufficient food production. Recently, biofilm-forming plant growth-promoting bacteria (PGPB) have emerged as promising candidates for agricultural application. These biofilms are evidence of microorganism colonization on plant roots. Their remarkable stress resilience empowers crops to thrive and yield even in harsh conditions. This is accomplished through increased root colonization, improved soil properties, and the synthesis of valuable secondary metabolites (e.g., ACC deaminase, acetin, 2,3-butanediol, proline, etc.). This article elucidates the mechanisms underpinning the role of biofilm-forming PGPB in bolstering plant growth amidst environmental challenges. Furthermore, it explores the tangible applications of these biofilms in agriculture and delves into strategies for manipulating biofilm formation to extract maximal benefits in practical crop production scenarios.
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Affiliation(s)
- Yujia Li
- College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Mathiyazhagan Narayanan
- Division of Research and Innovation, Department of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Science, Chennai 602105, Tamil Nadu, India
| | - Xiaojun Shi
- College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Xinping Chen
- College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Zhenlun Li
- College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Ying Ma
- College of Resources and Environment, Southwest University, Chongqing 400716, China.
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4
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Sher AW, Aufrecht JA, Herrera D, Zimmerman AE, Kim YM, Munoz N, Trejo JB, Paurus VL, Cliff JB, Hu D, Chrisler WB, Tournay RJ, Gomez-Rivas E, Orr G, Ahkami AH, Doty SL. Dynamic nitrogen fixation in an aerobic endophyte of Populus. THE ISME JOURNAL 2024; 18:wrad012. [PMID: 38365250 PMCID: PMC10833079 DOI: 10.1093/ismejo/wrad012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 11/11/2023] [Accepted: 11/21/2023] [Indexed: 02/18/2024]
Abstract
Biological nitrogen fixation by microbial diazotrophs can contribute significantly to nitrogen availability in non-nodulating plant species. In this study of molecular mechanisms and gene expression relating to biological nitrogen fixation, the aerobic nitrogen-fixing endophyte Burkholderia vietnamiensis, strain WPB, isolated from Populus trichocarpa served as a model for endophyte-poplar interactions. Nitrogen-fixing activity was observed to be dynamic on nitrogen-free medium with a subset of colonies growing to form robust, raised globular like structures. Secondary ion mass spectrometry (NanoSIMS) confirmed that N-fixation was uneven within the population. A fluorescent transcriptional reporter (GFP) revealed that the nitrogenase subunit nifH is not uniformly expressed across genetically identical colonies of WPB and that only ~11% of the population was actively expressing the nifH gene. Higher nifH gene expression was observed in clustered cells through monitoring individual bacterial cells using single-molecule fluorescence in situ hybridization. Through 15N2 enrichment, we identified key nitrogenous metabolites and proteins synthesized by WPB and employed targeted metabolomics in active and inactive populations. We cocultivated WPB Pnif-GFP with poplar within a RhizoChip, a synthetic soil habitat, which enabled direct imaging of microbial nifH expression within root epidermal cells. We observed that nifH expression is localized to the root elongation zone where the strain forms a unique physical interaction with the root cells. This work employed comprehensive experimentation to identify novel mechanisms regulating both biological nitrogen fixation and beneficial plant-endophyte interactions.
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Affiliation(s)
- Andrew W Sher
- School of Environmental and Forest Sciences, College of the Environment, University of Washington, Seattle, WA, 98195-2100, United States
| | - Jayde A Aufrecht
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Daisy Herrera
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Amy E Zimmerman
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Young-Mo Kim
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Nathalie Munoz
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Jesse B Trejo
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Vanessa L Paurus
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - John B Cliff
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Dehong Hu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - William B Chrisler
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Robert J Tournay
- School of Environmental and Forest Sciences, College of the Environment, University of Washington, Seattle, WA, 98195-2100, United States
| | - Emma Gomez-Rivas
- School of Environmental and Forest Sciences, College of the Environment, University of Washington, Seattle, WA, 98195-2100, United States
| | - Galya Orr
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Amir H Ahkami
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, United States
| | - Sharon L Doty
- School of Environmental and Forest Sciences, College of the Environment, University of Washington, Seattle, WA, 98195-2100, United States
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5
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Yi S, Zhu Z, Li F, Zhu L, Wu C, Ge F, Ji X, Tian J. Metagenomic and proteomic insights into the self-adaptive cell surface hydrophobicity of Sphingomonas sp. strain PAH02 reducing the migration of cadmium-phenanthrene co-pollutant in rice. Environ Microbiol 2024; 26:e16577. [PMID: 38183371 DOI: 10.1111/1462-2920.16577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/21/2023] [Indexed: 01/08/2024]
Abstract
Cell surface hydrophobicity (CSH) dominates the interactions between rhizobacteria and pollutants at the soil-water interface, which is critical for understanding the dissipation of pollutants in the rhizosphere microzone of rice. Herein, we explored the effects of self-adaptive CSH of Sphingomonas sp. strain PAH02 on the translocation and biotransformation behaviour of cadmium-phenanthrene (Cd-Phe) co-pollutant in rice and rhizosphere microbiome. We evidenced that strain PAH02 reduced the adsorption of Cd-Phe co-pollutant on the rice root surface while enhancing the degradation of Phe and adsorption of Cd via its self-adaptive CSH in the hydroponic experiment. The significant upregulation of key protein expression levels such as MerR, ARHDs and enoyl-CoA hydratase/isomerase, ensures self-adaptive CSH to cope with the stress of Cd-Phe co-pollutant. Consistently, the bioaugmentation of strain PAH02 promoted the formation of core microbiota in the rhizosphere soil of rice (Oryza sativa L.), such as Bradyrhizobium and Streptomyces and induced gene enrichment of CusA and PobA that are strongly associated with pollutant transformation. Consequently, the contents of Cd and Phe in rice grains at maturity decreased by 17.2% ± 0.2% and 65.7% ± 0.3%, respectively, after the bioaugmentation of strain PAH02. These findings present new opportunities for the implementation of rhizosphere bioremediation strategies of co-contaminants in paddy fields.
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Affiliation(s)
- Shengwei Yi
- College of Environment and Resources, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental and Ecological Health, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental Behavior and Control Principle of New Pollutants, Xiangtan University, Xiangtan, China
| | - Zhongnan Zhu
- College of Environment and Resources, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental and Ecological Health, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental Behavior and Control Principle of New Pollutants, Xiangtan University, Xiangtan, China
| | - Feng Li
- College of Environment and Resources, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental and Ecological Health, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental Behavior and Control Principle of New Pollutants, Xiangtan University, Xiangtan, China
| | - Lizhong Zhu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Chen Wu
- College of Environment and Resources, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental and Ecological Health, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental Behavior and Control Principle of New Pollutants, Xiangtan University, Xiangtan, China
| | - Fei Ge
- College of Environment and Resources, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental and Ecological Health, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental Behavior and Control Principle of New Pollutants, Xiangtan University, Xiangtan, China
| | - Xionghui Ji
- Hunan Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, China
| | - Jiang Tian
- College of Environment and Resources, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental and Ecological Health, Xiangtan University, Xiangtan, China
- Hunan Provincial University Key Laboratory for Environmental Behavior and Control Principle of New Pollutants, Xiangtan University, Xiangtan, China
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6
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Wang D, Naqvi STA, Lei F, Zhang Z, Yu H, Ma LZ. Glycosyl hydrolase from Pseudomonas fluorescens inhibits the biofilm formation of Pseudomonads. Biofilm 2023; 6:100155. [PMID: 37928620 PMCID: PMC10622837 DOI: 10.1016/j.bioflm.2023.100155] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 11/07/2023] Open
Abstract
Biofilms are complex microbial communities embedded in extracellular matrix. Pathogens within the biofilm become more resistant to the antibiotics than planktonic counterparts. Novel strategies are required to encounter biofilms. Exopolysaccharides are one of the major components of biofilm matrix and play a vital role in biofilm architecture. In previous studies, a glycosyl hydrolase, PslGPA, from Pseudomonas aeruginosa was found to be able to inhibit biofilm formation by disintegrating exopolysaccharide in biofilms. Here, we investigate the potential spectrum of PslG homologous protein with anti-biofilm activity. One glycosyl hydrolase from Pseudomonas fluorescens, PslGPF, exhibits anti-biofilm activities and the key catalytic residues of PslGPF are conserved with those of PslGPA. PslGPF at concentrations as low as 50 nM efficiently inhibits the biofilm formation of P. aeruginosa and disassemble its preformed biofilm. Furthermore, PslGPF exhibits anti-biofilm activity on a series of Pseudomonads, including P. fluorescens, Pseudomonas stutzeri and Pseudomonas syringae pv. phaseolicola. PslGPF stays active under various temperatures. Our findings suggest that P. fluorescens glycosyl hydrolase PslGPF has potential to be a broad spectrum inhibitor on biofilm formation of a wide range of Pseudomonads.
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Affiliation(s)
- Di Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, PR China
| | - Syed Tatheer Alam Naqvi
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, PR China
| | - Fanglin Lei
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, PR China
- Yunnan University, Kunming, 650500, PR China
| | - Zhenyu Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, PR China
- University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Haiying Yu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, PR China
| | - Luyan Z. Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, PR China
- University of Chinese Academy of Sciences, Beijing, 100049, PR China
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7
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Fernández-Juárez V, Hallstrøm S, Pacherres CO, Wang J, Coll-Garcia G, Kühl M, Riemann L. Biofilm formation and cell plasticity drive diazotrophy in an anoxygenic phototrophic bacterium. Appl Environ Microbiol 2023; 89:e0102723. [PMID: 37882569 PMCID: PMC10686084 DOI: 10.1128/aem.01027-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/14/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The contribution of non-cyanobacterial diazotrophs (NCDs) to total N2 fixation in the marine water column is unknown, but their importance is likely constrained by the limited availability of dissolved organic matter and low O2 conditions. Light could support N2 fixation and growth by NCDs, yet no examples from bacterioplankton exist. In this study, we show that the phototrophic NCD, Rhodopseudomonas sp. BAL398, which is a member of the diazotrophic community in the surface waters of the Baltic Sea, can utilize light. Our study highlights the significance of biofilm formation for utilizing light and fixing N2 under oxic conditions and the role of cell plasticity in regulating these processes. Our findings have implications for the general understanding of the ecology and importance of NCDs in marine waters.
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Affiliation(s)
- Víctor Fernández-Juárez
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Søren Hallstrøm
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Cesar O. Pacherres
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jiaqi Wang
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Guillem Coll-Garcia
- Microbiology, Biology Department, University of the Balearic Islands, Palma de Mallorca, Spain
- Environmental Microbiology Group, Mediterranean Institute for Advanced Studies (CSIC-UIB), Esporles, Spain
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Zayed O, Hewedy OA, Abdelmoteleb A, Ali M, Youssef MS, Roumia AF, Seymour D, Yuan ZC. Nitrogen Journey in Plants: From Uptake to Metabolism, Stress Response, and Microbe Interaction. Biomolecules 2023; 13:1443. [PMID: 37892125 PMCID: PMC10605003 DOI: 10.3390/biom13101443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 10/29/2023] Open
Abstract
Plants uptake and assimilate nitrogen from the soil in the form of nitrate, ammonium ions, and available amino acids from organic sources. Plant nitrate and ammonium transporters are responsible for nitrate and ammonium translocation from the soil into the roots. The unique structure of these transporters determines the specificity of each transporter, and structural analyses reveal the mechanisms by which these transporters function. Following absorption, the nitrogen metabolism pathway incorporates the nitrogen into organic compounds via glutamine synthetase and glutamate synthase that convert ammonium ions into glutamine and glutamate. Different isoforms of glutamine synthetase and glutamate synthase exist, enabling plants to fine-tune nitrogen metabolism based on environmental cues. Under stressful conditions, nitric oxide has been found to enhance plant survival under drought stress. Furthermore, the interaction between salinity stress and nitrogen availability in plants has been studied, with nitric oxide identified as a potential mediator of responses to salt stress. Conversely, excessive use of nitrate fertilizers can lead to health and environmental issues. Therefore, alternative strategies, such as establishing nitrogen fixation in plants through diazotrophic microbiota, have been explored to reduce reliance on synthetic fertilizers. Ultimately, genomics can identify new genes related to nitrogen fixation, which could be harnessed to improve plant productivity.
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Affiliation(s)
- Omar Zayed
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 9250, USA;
- Genetics Department, Faculty of Agriculture, Menoufia University, Shebin El-Kom 32511, Egypt;
| | - Omar A. Hewedy
- Genetics Department, Faculty of Agriculture, Menoufia University, Shebin El-Kom 32511, Egypt;
- Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Ali Abdelmoteleb
- Botany Department, Faculty of Agriculture, Menoufia University, Shebin El-Kom 32511, Egypt;
| | - Mohammed Ali
- Maryout Research Station, Genetic Resources Department, Desert Research Center, 1 Mathaf El-Matarya St., El-Matareya, Cairo 11753, Egypt;
| | - Mohamed S. Youssef
- Botany and Microbiology Department, Faculty of Science, Kafrelsheikh University, Kafrelsheikh 33516, Egypt;
- Department of Plant Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ahmed F. Roumia
- Department of Agricultural Biochemistry, Faculty of Agriculture, Menoufia University, Shibin El-Kom 32514, Egypt;
| | - Danelle Seymour
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 9250, USA;
| | - Ze-Chun Yuan
- Agriculture and Agri-Food Canada, 1391 Sandford Street, London, ON N5V 4T3, Canada
- Department of Microbiology and Immunology, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
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9
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Lu C, Hei R, Song X, Fan Z, Guo D, Luo J, Ma Y. Metal oxide nanoparticles inhibit nitrogen fixation and rhizosphere colonization by inducing ROS in associative nitrogen-fixing bacteria Pseudomonas stutzeri A1501. CHEMOSPHERE 2023:139223. [PMID: 37327828 DOI: 10.1016/j.chemosphere.2023.139223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/26/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
The potential effects of engineered metal oxide nanoparticles (MONPs) on bacterial nitrogen fixation are of great concern. Herein, the impact and mechanism of the increasing-used MONPs, including TiO2, Al2O3, and ZnO nanoparticles (TiO2NP, Al2O3NP, and ZnONP, respectively), on nitrogenase activity was studied at the concentrations ranging from 0 to 10 mg L-1 using associative rhizosphere nitrogen-fixing bacteria Pseudomonas stutzeri A1501. Nitrogen fixation capacity was inhibited by MONPs in an increasing degree of TiO2NP < Al2O3NP < ZnONP. Realtime qPCR analysis showed that the expressions of nitrogenase synthesis-related genes, including nifA and nifH, were inhibited significantly when MONPs were added. MONPs could cause the explosion of intracellular ROS, and ROS not only changed the permeability of the membrane but also inhibited the expression of nifA and biofilm formation on the root surface. The repressed nifA gene could inhibit transcriptional activation of nif-specific genes, and ROS reduced the biofilm formation on the root surface which had a negative effect on resisting environmental stress. This study demonstrated that MONPs, including TiO2NP, Al2O3NP, and ZnONP, inhibited bacterial biofilm formation and nitrogen fixation in the rice rhizosphere, which might have a negative effect on the nitrogen cycle in bacteria-rice system.
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Affiliation(s)
- Chao Lu
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
| | - Ruonan Hei
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China
| | - Xiuchao Song
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China
| | - Zixian Fan
- GenScript Biotech, Nanjing, 210003, China
| | - Dejie Guo
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China
| | - Jia Luo
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
| | - Yan Ma
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China.
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10
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Adeniyi A, Bello I, Mukaila T, Sarker NC, Hammed A. Trends in Biological Ammonia Production. BIOTECH 2023; 12:biotech12020041. [PMID: 37218758 DOI: 10.3390/biotech12020041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/01/2023] [Accepted: 05/16/2023] [Indexed: 05/24/2023] Open
Abstract
Food production heavily depends on ammonia-containing fertilizers to improve crop yield and profitability. However, ammonia production is challenged by huge energy demands and the release of ~2% of global CO2. To mitigate this challenge, many research efforts have been made to develop bioprocessing technologies to make biological ammonia. This review presents three different biological approaches that drive the biochemical mechanisms to convert nitrogen gas, bioresources, or waste to bio-ammonia. The use of advanced technologies-enzyme immobilization and microbial bioengineering-enhanced bio-ammonia production. This review also highlighted some challenges and research gaps that require researchers' attention for bio-ammonia to be industrially pragmatic.
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Affiliation(s)
- Adewale Adeniyi
- Environmental and Conservation Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Ibrahim Bello
- Agricultural and Biosystems Engineering, North Dakota State University, Fargo, ND 58102, USA
| | - Taofeek Mukaila
- Environmental and Conservation Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Niloy Chandra Sarker
- Agricultural and Biosystems Engineering, North Dakota State University, Fargo, ND 58102, USA
| | - Ademola Hammed
- Agricultural and Biosystems Engineering, North Dakota State University, Fargo, ND 58102, USA
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11
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Ramos G, Toulouze C, Rima M, Liot O, Duru P, Davit Y. Ultraviolet control of bacterial biofilms in microfluidic chips. BIOMICROFLUIDICS 2023; 17:024107. [PMID: 37124629 PMCID: PMC10132849 DOI: 10.1063/5.0135722] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 04/04/2023] [Indexed: 05/03/2023]
Abstract
Polydimethylsiloxane (PDMS) microfluidic systems have been instrumental in better understanding couplings between physical mechanisms and bacterial biofilm processes, such as hydrodynamic effects. However, precise control of the growth conditions, for example, the initial distribution of cells on the substrate or the boundary conditions in a flow system, has remained challenging. Furthermore, undesired bacterial colonization in crucial parts of the systems, in particular, in mixing zones or tubing, is an important factor that strongly limits the duration of the experiments and, therefore, impedes our ability to study the biophysics of biofilm evolving over long periods of time, as found in the environment, in engineering, or in medicine. Here, we develop a new approach that uses ultraviolet-C (UV-C) light-emitting diodes (LEDs) to confine bacterial development to specific zones of interest in the flow channels. The LEDs are integrated into a 3D printed light guide that is positioned upon the chip and used to irradiate germicidal UV-C directly through the PDMS. We first demonstrate that this system is successful in controlling undesired growth of Pseudomonas aeruginosa biofilm in inlet and outlet mixing zones during 48 h. We further illustrate how this can be used to define the initial distribution of bacteria to perturb already formed biofilms during an experiment and to control colonization for seven days-and possibly longer periods of time-therefore opening the way toward long-term biofilm experiments in microfluidic devices. Our approach is easily generalizable to existing devices at low cost and may, thus, become a standard in biofilm experiments in PDMS microfluidics.
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Affiliation(s)
- Gabriel Ramos
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
| | - Clara Toulouze
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
| | - Maya Rima
- Laboratoire de Génie Chimique (LGC), Université de Toulouse, CNRS, INPT, UPS, 31062 Toulouse, France
| | - Olivier Liot
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
| | - Paul Duru
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
| | - Yohan Davit
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
- Author to whom correspondence should be addressed:
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12
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Plant Growth-Promoting Bacteria (PGPB) with Biofilm-Forming Ability: A Multifaceted Agent for Sustainable Agriculture. DIVERSITY 2023. [DOI: 10.3390/d15010112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Plant growth-promoting bacteria (PGPB) enhance plant growth, as well as protect plants from several biotic and abiotic stresses through a variety of mechanisms. Therefore, the exploitation of PGPB in agriculture is feasible as it offers sustainable and eco-friendly approaches to maintaining soil health while increasing crop productivity. The vital key of PGPB application in agriculture is its effectiveness in colonizing plant roots and the phyllosphere, and in developing a protective umbrella through the formation of microcolonies and biofilms. Biofilms offer several benefits to PGPB, such as enhancing resistance to adverse environmental conditions, protecting against pathogens, improving the acquisition of nutrients released in the plant environment, and facilitating beneficial bacteria–plant interactions. Therefore, bacterial biofilms can successfully compete with other microorganisms found on plant surfaces. In addition, plant-associated PGPB biofilms are capable of protecting colonization sites, cycling nutrients, enhancing pathogen defenses, and increasing tolerance to abiotic stresses, thereby increasing agricultural productivity and crop yields. This review highlights the role of biofilms in bacterial colonization of plant surfaces and the strategies used by biofilm-forming PGPB. Moreover, the factors influencing PGPB biofilm formation at plant root and shoot interfaces are critically discussed. This will pave the role of PGPB biofilms in developing bacterial formulations and addressing the challenges related to their efficacy and competence in agriculture for sustainability.
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13
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Ammonia Production Using Bacteria and Yeast toward a Sustainable Society. BIOENGINEERING (BASEL, SWITZERLAND) 2023; 10:bioengineering10010082. [PMID: 36671654 PMCID: PMC9854848 DOI: 10.3390/bioengineering10010082] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/29/2022] [Accepted: 01/05/2023] [Indexed: 01/11/2023]
Abstract
Ammonia is an important chemical that is widely used in fertilizer applications as well as in the steel, chemical, textile, and pharmaceutical industries, which has attracted attention as a potential fuel. Thus, approaches to achieve sustainable ammonia production have attracted considerable attention. In particular, biological approaches are important for achieving a sustainable society because they can produce ammonia under mild conditions with minimal environmental impact compared with chemical methods. For example, nitrogen fixation by nitrogenase in heterogeneous hosts and ammonia production from food waste using microorganisms have been developed. In addition, crop production using nitrogen-fixing bacteria has been considered as a potential approach to achieving a sustainable ammonia economy. This review describes previous research on biological ammonia production and provides insights into achieving a sustainable society.
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14
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Chu D, Wang X, Fan J, Peng L, Liang J, Zheng Y, Wang R, You X, Jing C, Clark J, Li Y, Yuan Y. Ulva prolifera polysaccharide enhances the root colonisation by Bacillus amyloliquefaciens strain Cas02. Carbohydr Polym 2023; 299:120171. [PMID: 36876786 DOI: 10.1016/j.carbpol.2022.120171] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/15/2022] [Accepted: 09/26/2022] [Indexed: 10/14/2022]
Abstract
The application of biocontrol agent is important for the sustainable development of agriculture. Unsuccessful or limited colonisation by plant growth-promoting rhizobacteria (PGPR) has become an important constraint factor for their commercial application. Here, we report that Ulva prolifera polysaccharide (UPP) promotes root colonisation by Bacillus amyloliquefaciens strain Cas02. UPP serves as an environmental signal for bacterial biofilm formation and its glucose residue is used as a carbon source for the synthesis of the exopolysaccharides and poly-gamma-glutamate present in biofilm matrix. Greenhouse experiments demonstrated that UPP could effectively enhance the root colonisation by Cas02 in both the bacterial population and survival time under natural semiarid soil conditions. Furthermore, the microbiome analysis also indicated the promoted colonisation by Cas02, as well as the improved bacterial rhizosphere community structure, after combined treatment of UPP and Cas02. This study provides a practical approach to improve the biocontrol agent with seaweed polysaccharides.
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Affiliation(s)
- Depeng Chu
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Xiaoqiang Wang
- Key Laboratory of Tobacco Pest Monitoring & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Jiajun Fan
- Green Chemistry Centre of Excellence, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Lijuan Peng
- Yunnan Tobacco Quality Supervision and Test Station, Kunming 650106, China
| | - Jinchang Liang
- Key Laboratory of Tobacco Pest Monitoring & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Yanfen Zheng
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Rui Wang
- Enshi Tobacco Science and Technology Center, Enshi 445000, China
| | - Xiangwei You
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Changliang Jing
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - James Clark
- Green Chemistry Centre of Excellence, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Yiqiang Li
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China.
| | - Yuan Yuan
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China.
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15
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Guo DJ, Singh P, Yang B, Singh RK, Verma KK, Sharma A, Khan Q, Qin Y, Chen TS, Song XP, Zhang BQ, Li DP, Li YR. Complete genome analysis of sugarcane root associated endophytic diazotroph Pseudomonas aeruginosa DJ06 revealing versatile molecular mechanism involved in sugarcane development. Front Microbiol 2023; 14:1096754. [PMID: 37152763 PMCID: PMC10157262 DOI: 10.3389/fmicb.2023.1096754] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 03/27/2023] [Indexed: 05/09/2023] Open
Abstract
Sugarcane is an important sugar and bioenergy source and a significant component of the economy in various countries in arid and semiarid. It requires more synthetic fertilizers and fungicides during growth and development. However, the excess use of synthetic fertilizers and fungicides causes environmental pollution and affects cane quality and productivity. Plant growth-promoting bacteria (PGPB) indirectly or directly promote plant growth in various ways. In this study, 22 PGPB strains were isolated from the roots of the sugarcane variety GT42. After screening of plant growth-promoting (PGP) traits, it was found that the DJ06 strain had the most potent PGP activity, which was identified as Pseudomonas aeruginosa by 16S rRNA gene sequencing. Scanning electron microscopy (SEM) and green fluorescent protein (GFP) labeling technology confirmed that the DJ06 strain successfully colonized sugarcane tissues. The complete genome sequencing of the DJ06 strain was performed using Nanopore and Illumina sequencing platforms. The results showed that the DJ06 strain genome size was 64,90,034 bp with a G+C content of 66.34%, including 5,912 protein-coding genes (CDSs) and 12 rRNA genes. A series of genes related to plant growth promotion was observed, such as nitrogen fixation, ammonia assimilation, siderophore, 1-aminocyclopropane-1-carboxylic acid (ACC), deaminase, indole-3-acetic acid (IAA) production, auxin biosynthesis, phosphate metabolism, hydrolase, biocontrol, and tolerance to abiotic stresses. In addition, the effect of the DJ06 strain was also evaluated by inoculation in two sugarcane varieties GT11 and B8. The length of the plant was increased significantly by 32.43 and 12.66% and fresh weight by 89.87 and 135.71% in sugarcane GT11 and B8 at 60 days after inoculation. The photosynthetic leaf gas exchange also increased significantly compared with the control plants. The content of indole-3-acetic acid (IAA) was enhanced and gibberellins (GA) and abscisic acid (ABA) were reduced in response to inoculation of the DJ06 strain as compared with control in two sugarcane varieties. The enzymatic activities of oxidative, nitrogen metabolism, and hydrolases were also changed dramatically in both sugarcane varieties with inoculation of the DJ06 strain. These findings provide better insights into the interactive action mechanisms of the P. aeruginosa DJ06 strain and sugarcane plant development.
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Affiliation(s)
- Dao-Jun Guo
- College of Life Sciences and Engineering, Hexi University, Zhangye, Gansu, China
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Pratiksha Singh
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Bin Yang
- College of Life Sciences and Engineering, Hexi University, Zhangye, Gansu, China
| | - Rajesh Kumar Singh
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Krishan K. Verma
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Anjney Sharma
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Qaisar Khan
- College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Ying Qin
- College of Agriculture, Guangxi University, Nanning, Guangxi, China
| | - Ting-Su Chen
- Microbiology Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Xiu-Peng Song
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Bao-Qing Zhang
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Dong-Ping Li
- Microbiology Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
- Dong-Ping Li
| | - Yang-Rui Li
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
- *Correspondence: Yang-Rui Li
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16
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AlSalhi MS, Devanesan S, Rajasekar A, Kokilaramani S. Characterization of plants and seaweeds based corrosion inhibitors against microbially influenced corrosion in a cooling tower water environment. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.104513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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17
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Joublin-Delavat A, Touahri K, Crétin P, Morot A, Rodrigues S, Jesus B, Trigodet F, Delavat F. Genetic and physiological insights into the diazotrophic activity of a non-cyanobacterial marine diazotroph. Environ Microbiol 2022; 24:6510-6523. [PMID: 36302093 PMCID: PMC10099842 DOI: 10.1111/1462-2920.16261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 10/21/2022] [Indexed: 01/12/2023]
Abstract
Nitrogen (N2 ) fixation, or diazotrophy, supports a large part of primary production in oceans. Culture-independent approaches highlighted the presence in abundance of marine non-cyanobacterial diazotrophs (NCD), but their ecophysiology remains elusive, mostly because of the low number of isolated NCD and because of the lack of available genetic tools for these isolates. Here, a dual genetic and functional approach allowed unveiling the ecophysiology of a marine NCD affiliated to the species Vibrio diazotrophicus. Physiological characterization of the first marine NCD mutant obtained so far was performed using a soft-gellan assay, demonstrating that a ΔnifH mutant is not able to grow in nitrogen-free media. Furthermore, we demonstrated that V. diazotrophicus produces a thick biofilm under diazotrophic conditions, suggesting biofilm production as an adaptive response of this NCD to cope with the inhibition of nitrogen fixation by molecular oxygen. Finally, the genomic signature of V. diazotrophicus is essentially absent from metagenomic data of Tara Ocean expeditions, despite having been isolated from various marine environments. We think that the genetically tractable V. diazotrophicus strain used in this study may serve as an ideal model to study the ecophysiology of these overlooked procaryotic group.
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Affiliation(s)
| | - Katia Touahri
- Nantes Université, CNRS, US2B, UMR6286, Nantes, France.,Laboratoire Chimie et Biochimie de Molécules Bioactives, Université de Strasbourg/CNRS, UMR7177, Strasbourg, France
| | | | - Amandine Morot
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, Plouzané, France.,Université de Bretagne-Sud, UR3884, LBCM, IUEM, Lorient, France
| | | | - Bruno Jesus
- Nantes Université, RSBE2 ISOMer, UR2160, Nantes, France
| | - Florian Trigodet
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
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18
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Mokeev DI, Volokhina IV, Telesheva EM, Evstigneeva SS, Grinev VS, Pylaev TE, Petrova LP, Shelud’ko AV. Resistance of Biofilms Formed by the Soil Bacterium Azospirillum brasilense to Osmotic Stress. Microbiology (Reading) 2022. [DOI: 10.1134/s0026261722601567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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19
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Yan D, Tajima H, Cline LC, Fong RY, Ottaviani JI, Shapiro H, Blumwald E. Genetic modification of flavone biosynthesis in rice enhances biofilm formation of soil diazotrophic bacteria and biological nitrogen fixation. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:2135-2148. [PMID: 35869808 PMCID: PMC9616522 DOI: 10.1111/pbi.13894] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/05/2022] [Accepted: 07/15/2022] [Indexed: 05/06/2023]
Abstract
Improving biological nitrogen fixation (BNF) in cereal crops is a long-sought objective; however, no successful modification of cereal crops showing increased BNF has been reported. Here, we described a novel approach in which rice plants were modified to increase the production of compounds that stimulated biofilm formation in soil diazotrophic bacteria, promoted bacterial colonization of plant tissues and improved BNF with increased grain yield at limiting soil nitrogen contents. We first used a chemical screening to identify plant-produced compounds that induced biofilm formation in nitrogen-fixing bacteria and demonstrated that apigenin and other flavones induced BNF. We then used CRISPR-based gene editing targeting apigenin breakdown in rice, increasing plant apigenin contents and apigenin root exudation. When grown at limiting soil nitrogen conditions, modified rice plants displayed increased grain yield. Biofilm production also modified the root microbiome structure, favouring the enrichment of diazotrophic bacteria recruitment. Our results support the manipulation of the flavone biosynthetic pathway as a feasible strategy for the induction of biological nitrogen fixation in cereals and a reduction in the use of inorganic nitrogen fertilizers.
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Affiliation(s)
- Dawei Yan
- Department of Plant SciencesUniversity of CaliforniaDavisCaliforniaUSA
| | - Hiromi Tajima
- Department of Plant SciencesUniversity of CaliforniaDavisCaliforniaUSA
| | | | - Reedmond Y. Fong
- Department of NutritionUniversity of CaliforniaDavisCaliforniaUSA
| | - Javier I. Ottaviani
- Department of NutritionUniversity of CaliforniaDavisCaliforniaUSA
- Mars Inc.McLeanVirginiaUSA
| | | | - Eduardo Blumwald
- Department of Plant SciencesUniversity of CaliforniaDavisCaliforniaUSA
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20
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Molecular Origins of Transcriptional Heterogeneity in Diazotrophic Klebsiella oxytoca. mSystems 2022; 7:e0059622. [PMID: 36073804 PMCID: PMC9600154 DOI: 10.1128/msystems.00596-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Phenotypic heterogeneity in clonal bacterial batch cultures has been shown for a range of bacterial systems; however, the molecular origins of such heterogeneity and its magnitude are not well understood. Under conditions of extreme low-nitrogen stress in the model diazotroph Klebsiella oxytoca, we found remarkably high heterogeneity of nifHDK gene expression, which codes for the structural genes of nitrogenase, one key enzyme of the global nitrogen cycle. This heterogeneity limited the bulk observed nitrogen-fixing capacity of the population. Using dual-probe, single-cell RNA fluorescent in situ hybridization, we correlated nifHDK expression with that of nifLA and glnK-amtB, which code for the main upstream regulatory components. Through stochastic transcription models and mutual information analysis, we revealed likely molecular origins for heterogeneity in nitrogenase expression. In the wild type and regulatory variants, we found that nifHDK transcription was inherently bursty, but we established that noise propagation through signaling was also significant. The regulatory gene glnK had the highest discernible effect on nifHDK variance, while noise from factors outside the regulatory pathway were negligible. Understanding the basis of inherent heterogeneity of nitrogenase expression and its origins can inform biotechnology strategies seeking to enhance biological nitrogen fixation. Finally, we speculate on potential benefits of diazotrophic heterogeneity in natural soil environments. IMPORTANCE Nitrogen is an essential micronutrient for both plant and animal life and naturally exists in both reactive and inert chemical forms. Modern agriculture is heavily reliant on nitrogen that has been "fixed" into a reactive form via the energetically expensive Haber-Bosch process, with significant environmental consequences. Nitrogen-fixing bacteria provide an alternative source of fixed nitrogen for use in both biotechnological and agricultural settings, but this relies on a firm understanding of how the fixation process is regulated within individual bacterial cells. We examined the cell-to-cell variability in the nitrogen-fixing behavior of Klebsiella oxytoca, a free-living bacterium. The significance of our research is in identifying not only the presence of marked variability but also the specific mechanisms that give rise to it. This understanding gives insight into both the evolutionary advantages of variable behavior as well as strategies for biotechnological applications.
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21
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Li H, Wei Z, Song C, Chen X, Zhang R, Liu Y. Functional keystone drive nitrogen conversion during different animal manures composting. BIORESOURCE TECHNOLOGY 2022; 361:127721. [PMID: 35914672 DOI: 10.1016/j.biortech.2022.127721] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
In this study, nitrogen transformation of chicken manure (CM) and cattle dung (CD) during composting was analyzed and its related functional keystones were identified. The results showed that chicken manure showed more severe nitrogen conversion during composting. The main N conversion factors in cattle dung were nitrite nitrogen (NO2--N) and ammonium nitrogen (NH4+-N), while the main N conversion factors in chicken manure were NH4+-N and nitrate nitrogen (NO3--N). The nitrogen-transforming bacterial community in chicken manure was more diverse. Variations in functional keystone abundances in cattle dung tended to be confined to the cooling and maturation periods, whereas changes in chicken manure persisted throughout the composting process. Environmental factors affected the functional keystones of nitrogen transformation. This study may provide directions for regulating nitrogen conversion in animal manure composting.
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Affiliation(s)
- Huiying Li
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Zimin Wei
- College of Life Science, Northeast Agricultural University, Harbin 150030, China.
| | - Caihong Song
- College of Life Science, Liaocheng University, Liaocheng 252000, China
| | - Xiaomeng Chen
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Ruju Zhang
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Yumeng Liu
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
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22
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Nair S, Zhang Z, Li H, Zhao H, Shen H, Kao SJ, Jiao N, Zhang Y. Inherent tendency of Synechococcus and heterotrophic bacteria for mutualism on long-term coexistence despite environmental interference. SCIENCE ADVANCES 2022; 8:eabf4792. [PMID: 36179022 PMCID: PMC9524826 DOI: 10.1126/sciadv.abf4792] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 08/17/2022] [Indexed: 06/12/2023]
Abstract
Mutualism between Synechococcus and heterotrophic bacteria has been found to support their prolonged survival in nutrient-depleted conditions. However, environmental interference on the fate of their mutualism is not understood. Here, we show that exogenous nutrients disrupt their established mutualism. Once the exogenous nutrients were exhausted, Synechococcus and heterotrophic bacteria gradually reestablished their metabolic mutualism during 450 days of culture, which revived unhealthy Synechococcus cells. Using metagenomics, metatranscriptomics, and the 15N tracer method, we reveal that the associated bacterial nitrogen fixation triggered the reestablishment of the mutualism and revival of Synechococcus health. During this process, bacterial community structure and functions underwent tremendous adjustments to achieve the driving effect, and a cogeneration of nitrogen, phosphorus, iron, and vitamin by the heterotrophic bacteria sustained Synechococcus's prolonged healthy growth. Our findings suggest that Synechococcus and heterotrophic bacteria may have an inherent tendency toward mutualism despite environmental interference. This may exhibit their coevolutionary adaptations in nutrient-deficient environments.
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Affiliation(s)
- Shailesh Nair
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zenghu Zhang
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongmei Li
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanshuang Zhao
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hui Shen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361101, China
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou 570228, China
| | - Shuh-Ji Kao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361101, China
- State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou 570228, China
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361101, China
| | - Yongyu Zhang
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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23
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Chen Z, Dolfing J, Zhuang S, Wu Y. Periphytic biofilms-mediated microbial interactions and their impact on the nitrogen cycle in rice paddies. ECO-ENVIRONMENT & HEALTH (ONLINE) 2022; 1:172-180. [PMID: 38075597 PMCID: PMC10702904 DOI: 10.1016/j.eehl.2022.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 09/13/2022] [Accepted: 09/29/2022] [Indexed: 01/03/2024]
Abstract
Rice paddies are unique waterlogged wetlands artificially constructed for agricultural production. Periphytic biofilms (PBs) at the soil-water interface play an important role in rice paddies characterized by high nutrient input but low utilization efficiency. PBs are composed of microbial aggregates, including a wide variety of microorganisms (algae, bacteria, fungi, protozoa, and metazoa), extracellular polymeric substances and minerals (iron, aluminum, and calcium), which form an integrated food web and energy flux within a relatively stable micro-ecosystem. PBs are crucial to regulate and streamline the nitrogen cycle by neutralizing nitrogen losses and improving rice production since PBs can serve as both a sink by capturing surplus nitrogen and a source by slowly re-releasing this nitrogen for reutilization. Here the ecological advantages of PBs in regulating the nitrogen cycle in rice paddies are illustrated. We summarize the key functional importance of PBs, including the intricate and delicate community structure, microbial interactions among individual phylotypes, a wide diversity of self-produced organics, the active adaptation of PBs to constantly changing environments, and the intricate mechanisms by which PBs regulate the nitrogen cycle. We also identify the future challenges of microbial interspecific cooperation in PBs and their quantitative contributions to agricultural sustainability, optimizing nitrogen utilization and crop yields in rice paddies.
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Affiliation(s)
- Zhihao Chen
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Yichang 443605, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jan Dolfing
- Faculty of Energy and Environment, Northumbria University, Newcastle Upon Tyne NE1 8QH, UK
| | - Shunyao Zhuang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yonghong Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- Zigui Three Gorges Reservoir Ecosystem, Observation and Research Station of Ministry of Water Resources of the People's Republic of China, Yichang 443605, China
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Shi L, Cai Y, Gao S, Fang D, Lu Y, Li P, Wu QL. Gene expression in the microbial consortia of colonial Microcystis aeruginosa-a potential buoyant particulate biofilm. Environ Microbiol 2022; 24:4931-4945. [PMID: 35837847 DOI: 10.1111/1462-2920.16133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 06/29/2022] [Accepted: 07/07/2022] [Indexed: 11/28/2022]
Abstract
Microcystis spp., notorious bloom-forming cyanobacteria, are often present in colony form in eutrophic lakes worldwide. Uncovering the mechanisms underlying Microcystis colony formation and maintenance is vital to control the blooms, but it has long been a challenge. Here, bacterial communities and gene expression patterns of colonial and unicellular forms of one non-axenic strain of Microcystis aeruginosa isolated from Lake Taihu were compared. Evidently, different microbial communities between them were observed through 16S rDNA MiSeq sequencing. Metatranscriptome analyses revealed that transcripts for pathways involved in bacterial biofilm formation, such as biosynthesis of peptidoglycan and arginine by Bacteroidetes, methionine biosynthesis, alginate metabolism, flagellum, and motility, as well as widespread colonization islands by Proteobacteria, were highly enriched in the colonial form. Furthermore, transcripts for nitrogen fixation and denitrification pathways by Proteobacteria that usually occur in biofilms were significantly enriched in the colonial Microcystis. Results revealed that microbes associated with Microcystis colonies play important roles through regulation of biofilm-related genes in colony formation and maintenance. Moreover, Microcystis colony represents a potential "buoyant particulate biofilm", which is a good model for biofilm studies. The biofilm features of colonial Microcystis throw a new light on management and control of the ubiquitous blooms in eutrophic waters. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Limei Shi
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, China
| | - Yuanfeng Cai
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province, China
| | - Shengling Gao
- Biological Experiment Teaching Center, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Daoyan Fang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, P.R. China
| | - Yaping Lu
- Biological Experiment Teaching Center, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Pengfu Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, P.R. China
| | - Qinglong L Wu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing, China.,Sino-Danish Center for Science and Education, University of Chinese Academy of Sciences, Beijing, P.R. China.,The Fuxianhu Station of Plateau Deep Lake Research, Chinese Academy of Sciences, Chengjiang, Yunnan Province, P.R. China
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25
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Control of nitrogen fixation and ammonia excretion in Azorhizobium caulinodans. PLoS Genet 2022; 18:e1010276. [PMID: 35727841 PMCID: PMC9249168 DOI: 10.1371/journal.pgen.1010276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/01/2022] [Accepted: 05/26/2022] [Indexed: 11/19/2022] Open
Abstract
Due to the costly energy demands of nitrogen (N) fixation, diazotrophic bacteria have evolved complex regulatory networks that permit expression of the catalyst nitrogenase only under conditions of N starvation, whereas the same condition stimulates upregulation of high-affinity ammonia (NH3) assimilation by glutamine synthetase (GS), preventing excess release of excess NH3 for plants. Diazotrophic bacteria can be engineered to excrete NH3 by interference with GS, however control is required to minimise growth penalties and prevent unintended provision of NH3 to non-target plants. Here, we tested two strategies to control GS regulation and NH3 excretion in our model cereal symbiont Azorhizobium caulinodans AcLP, a derivative of ORS571. We first attempted to recapitulate previous work where mutation of both PII homologues glnB and glnK stimulated GS shutdown but found that one of these genes was essential for growth. Secondly, we expressed unidirectional adenylyl transferases (uATs) in a ΔglnE mutant of AcLP which permitted strong GS shutdown and excretion of NH3 derived from N2 fixation and completely alleviated negative feedback regulation on nitrogenase expression. We placed a uAT allele under control of the NifA-dependent promoter PnifH, permitting GS shutdown and NH3 excretion specifically under microaerobic conditions, the same cue that initiates N2 fixation, then deleted nifA and transferred a rhizopine nifAL94Q/D95Q-rpoN controller plasmid into this strain, permitting coupled rhizopine-dependent activation of N2 fixation and NH3 excretion. This highly sophisticated and multi-layered control circuitry brings us a step closer to the development of a "synthetic symbioses” where N2 fixation and NH3 excretion could be specifically activated in diazotrophic bacteria colonising transgenic rhizopine producing cereals, targeting delivery of fixed N to the crop while preventing interaction with non-target plants. Inoculation of cereal crops with associative diazotrophic bacteria that convert atmospheric nitrogen (N2) into ammonia (NH3) could be used to sustainably improve delivery of nitrogen to crops. However, due to the costly energy demands of N2 fixation, bacteria restrict excess production of NH3 and release to the plants. Diazotrophs can be engineered for excess NH3 production and release, however genetic control is required to minimise growth penalties and prevent unintended provision of NH3 to non-target weed species. Here, we engineer coupled control of N2 fixation and NH3 release in response to the signalling molecule rhizopine supplemented in vitro. This control circuitry represents a prototype for the future development of a “synthetic symbiosis” where bacterial N2 fixation and NH3 excretion could be specifically activated following colonisation of transgenic rhizopine producing cereals in the field, minimising bacterial energy requirements and preventing provision of NH3 to non-target plants.
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Li W, Siddique MS, Graham N, Yu W. Influence of Temperature on Biofilm Formation Mechanisms Using a Gravity-Driven Membrane (GDM) System: Insights from Microbial Community Structures and Metabolomics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:8908-8919. [PMID: 35623093 DOI: 10.1021/acs.est.2c01243] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A biofilm has a significant effect on water treatment processes. Currently, there is a lack of knowledge about the effect of temperature on the biofilm structure in water treatment processes. In this study, a gravity-driven membrane ultrafiltration system was operated with river feedwater at two temperatures ("low", 4 °C; "high", 25 °C) to explore the biofilm structure and transformation mechanism. The results showed that the difference in dissolved oxygen concentration might be one of the main factors regulating the structural components of the biofilm. A denser biofilm formation and reduced flux were observed at the lower temperature. The linoleic acid metabolism was significantly inhibited at low temperature, resulting in enhanced pyrimidine metabolism by Na+ accumulation. In addition, the biofilm at low temperature had a higher proportion of the metabolites of lipids and lipid-like molecules (11.25%), organic acids and derivatives (10.83%), nucleosides, nucleotides, and analogues (7.083%), and organoheterocyclic compounds (6.66%). These small molecules secrete more polysaccharides having C═O and O═C-O functional groups, which intensified the resistance of the biofilm. Furthermore, the upregulation pathway of pyrimidine metabolism also increased the risk of urea accumulation at low temperature. Limnohabitans, Deinococcus, Diaphorobacter, Flavobacterium, and Pseudomonas were identified as the principal microorganisms involved in this metabolic transformation.
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Affiliation(s)
- Weihua Li
- State Key Laboratory of Environmental Aquatic Chemistry, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Muhammad Saboor Siddique
- State Key Laboratory of Environmental Aquatic Chemistry, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Nigel Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Wenzheng Yu
- State Key Laboratory of Environmental Aquatic Chemistry, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China
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Pathania N, Kumar A, Sharma P, Kaur A, Sharma S, Jain R. Harnessing rhizobacteria to fulfil inter-linked nutrient dependency on soil and alleviate stresses in plants. J Appl Microbiol 2022; 133:2694-2716. [PMID: 35656999 DOI: 10.1111/jam.15649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 05/12/2022] [Accepted: 05/31/2022] [Indexed: 11/27/2022]
Abstract
Plant rhizo-microbiome comprises of complex microbial communities that colonizes at the interphase of plant roots and soil. Plant-growth-promoting rhizobacteria (PGPR) in the rhizosphere provides important ecosystem services ranging from release of essential nutrients for enhancing soil quality and improving plant health to imparting protection to plants against rising biotic and abiotic stresses. Hence, PGPR serve as restoring agents to rejuvenate soil health and mediate plant fitness in the facet of changing climate. Though, it is evident that nutrients availability in soil are managed through inter-linked mechanisms, how PGPR expediate these processes remain less recognized. Promising results of PGPR inoculation on plant growth are continually reported in controlled environmental conditions, however, their field application often fails due to competition with native microbiota and low colonization efficiency in roots. The development of highly efficient and smart bacterial synthetic communities by integrating bacterial ecological and genetic features provides better opportunities for successful inoculant formulations. This review provides an overview of the inter-play between nutrient availability and disease suppression governed by rhizobacteria in soil followed by the role of synthetic bacterial communities in developing efficient microbial inoculants. Moreover, an outlook on the beneficial activities of rhizobacteria in modifying soil characteristics to sustainably boost agroecosystem functioning is also provided.
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Affiliation(s)
- Neemisha Pathania
- Department of Soil Science, Punjab Agricultural University, Ludhiana, Punjab 141004, India
| | - Arun Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India
| | - Poonam Sharma
- Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, Punjab 141004, India
| | - Avneet Kaur
- Department of Soil Science, Punjab Agricultural University, Ludhiana, Punjab 141004, India
| | - Sandeep Sharma
- Department of Soil Science, Punjab Agricultural University, Ludhiana, Punjab 141004, India
| | - Rahul Jain
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India
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Bulk and Spatially Resolved Extracellular Metabolome of Free-Living Nitrogen Fixation. Appl Environ Microbiol 2022; 88:e0050522. [PMID: 35652664 PMCID: PMC9238392 DOI: 10.1128/aem.00505-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Soil nitrogen (N) transformations constrain terrestrial net primary productivity and are driven by the activity of soil microorganisms. Free-living N fixation (FLNF) is an important soil N transformation and key N input to terrestrial systems, but the forms of N contributed to soil by FLNF are poorly understood. To address this knowledge gap, a focus on microorganisms and microbial scale processes is needed that links N-fixing bacteria and their contributed N sources to FLNF process rates. However, studying the activity of soil microorganisms in situ poses inherent challenges, including differences in sampling scale between microorganism and process rates, which can be addressed with culture-based studies and an emphasis on microbial-scale measurements. Culture conditions can differ significantly from soil conditions, so it also important that such studies include multiple culture conditions like liquid and solid media as proxies for soil environments like soil pore water and soil aggregate surfaces. Here we characterized extracellular N-containing metabolites produced by two common, diazotrophic soil bacteria in liquid and solid media, with or without N, across two sampling scales (bulk via GC-MS and spatially resolved via MALDI mass spec imaging). We found extracellular production of inorganic and organic N during FLNF, indicating terrestrial N contributions from FLNF occur in multiple forms not only as ammonium as previously thought. Extracellular metabolite profiles differed between liquid and solid media supporting previous work indicating environmental structure influences microbial function. Metabolite profiles also differed between sampling scales underscoring the need to quantify microbial scale conditions to accurately interpret microbial function. IMPORTANCE Free-living nitrogen-fixing bacteria contribute significantly to terrestrial nitrogen availability; however, the forms of nitrogen contributed by this process are poorly understood. This is in part because of inherent challenges to studying soil microorganisms in situ, such as vast differences in scale between microorganism and ecosystem and complexities of the soil system (e.g., opacity, chemical complexity). Thus, upscaling important ecosystem processes driven by soil microorganisms, like free-living nitrogen fixation, requires microbial-scale measurements in controlled systems. Our work generated bulk and spatially resolved measurements of nitrogen released during free-living nitrogen fixation under two contrasting growth conditions analogous to soil pores and aggregates. This work allowed us to determine that diverse forms of nitrogen are likely contributed to terrestrial systems by free-living nitrogen bacteria. We also demonstrated that microbial habitat (e.g., liquid versus solid media) alters microbial activity and that measurement of microbial activity is altered by sampling scale (e.g., bulk versus spatially resolved) highlighting the critical importance of quantifying microbial-scale processes to upscaling of ecosystem function.
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29
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Shao Y, Yin C, Lv F, Jiang S, Wu S, Han Y, Xue W, Ma Y, Zheng J, Zhan Y, Ke X, Lu W, Lin M, Shang L, Yan Y. The Sigma Factor AlgU Regulates Exopolysaccharide Production and Nitrogen-Fixing Biofilm Formation by Directly Activating the Transcription of pslA in Pseudomonas stutzeri A1501. Genes (Basel) 2022; 13:genes13050867. [PMID: 35627252 PMCID: PMC9141998 DOI: 10.3390/genes13050867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 11/29/2022] Open
Abstract
Pseudomonas stutzeri A1501, a plant-associated diazotrophic bacterium, prefers to conform to a nitrogen-fixing biofilm state under nitrogen-deficient conditions. The extracytoplasmic function (ECF) sigma factor AlgU is reported to play key roles in exopolysaccharide (EPS) production and biofilm formation in the Pseudomonas genus; however, the function of AlgU in P. stutzeri A1501 is still unclear. In this work, we mainly investigated the role of algU in EPS production, biofilm formation and nitrogenase activity in A1501. The algU mutant ΔalgU showed a dramatic decrease both in the EPS production and the biofilm formation capabilities. In addition, the biofilm-based nitrogenase activity was reduced by 81.4% in the ΔalgU mutant. The transcriptional level of pslA, a key Psl-like (a major EPS in A1501) synthesis-related gene, was almost completely inhibited in the algU mutant and was upregulated by 2.8-fold in the algU-overexpressing strain. A predicted AlgU-binding site was identified in the promoter region of pslA. The DNase I footprinting assays indicated that AlgU could directly bind to the pslA promoter, and β-galactosidase activity analysis further revealed mutations of the AlgU-binding boxes drastically reduced the transcriptional activity of the pslA promoter; moreover, we also demonstrated that AlgU was positively regulated by RpoN at the transcriptional level and negatively regulated by the RNA-binding protein RsmA at the posttranscriptional level. Taken together, these data suggest that AlgU promotes EPS production and nitrogen-fixing biofilm formation by directly activating the transcription of pslA, and the expression of AlgU is controlled by RpoN and RsmA at different regulatory levels.
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Affiliation(s)
- Yahui Shao
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Changyan Yin
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Fanyang Lv
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Shanshan Jiang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Shaoyu Wu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Yueyue Han
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Wei Xue
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Yiyuan Ma
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Juan Zheng
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Yuhua Zhan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Xiubin Ke
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Wei Lu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Min Lin
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
| | - Liguo Shang
- School of Basic Medicine, GuangXi University of Chinese Medicine, Nanning 530200, China
- Correspondence: (L.S.); (Y.Y.)
| | - Yongliang Yan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (Y.S.); (C.Y.); (F.L.); (S.J.); (S.W.); (Y.H.); (W.X.); (Y.M.); (J.Z.); (Y.Z.); (X.K.); (W.L.); (M.L.)
- Correspondence: (L.S.); (Y.Y.)
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30
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Ouyang B, Liu F, Liang C, Zhang J, Hu R, Yuan H, Hai R, Yuan Y, Wu X, Yang ST. Toxicity and activity inhibition of metal-organic framework MOF-199 to nitrogen-fixing bacterium Azotobacter vinelandii. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 813:151912. [PMID: 34838921 DOI: 10.1016/j.scitotenv.2021.151912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 11/06/2021] [Accepted: 11/19/2021] [Indexed: 05/10/2023]
Abstract
Metal-organic framework (MOF) materials with fantastic properties have found important applications in various areas. Learning the lessons from plastics and microplastics, it is urgent to investigate the environmental impacts of emerging materials to avoid potential pollution. However, the environmental toxicity and risks of MOF materials are seldom reported. Herein, we studied the toxicity and activity inhibition of MOF-199 to nitrogen-fixing bacterium Azotobacter vinelandii. MOF-199 significantly suppressed the growth of A. vinelandii and led to cell death at 40 mg/L. MOF-199 penetrated the cell wall and induced the shrinking of bacterial cells. MOF-199 reduced the nitrogen fixation activity of A. vinelandii at 40 mg/L by decreasing the gene nifH levels and inhibiting the Ca2+Mg2+-ATPase activity, which was further confirmed by the changes in oxidative phosphorylation related genes. Complete growth inhibition and activity loss of A. vinelandii occurred at 60 mg/L of MOF-199. The toxicological mechanism of MOF-199 to A. vinelandii was assigned to the oxidative stress, which occurred at 20 mg/L and higher. Both Cu2+ release and particulates themselves contributed to the toxicity of MOF-199 to A. vinelandii. These findings highlighted the environmental hazards and risks of MOF materials to nitrogen-fixing bacteria and nitrogen fixation in the biogeochemical cycle.
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Affiliation(s)
- Bowei Ouyang
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Fangshi Liu
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Chengzhuang Liang
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Jiahao Zhang
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Ruonan Hu
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Huahui Yuan
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Ruiduo Hai
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Yue Yuan
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Xian Wu
- Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Sheng-Tao Yang
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China.
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31
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Nazari M, Bickel S, Benard P, Mason-Jones K, Carminati A, Dippold MA. Biogels in Soils: Plant Mucilage as a Biofilm Matrix That Shapes the Rhizosphere Microbial Habitat. FRONTIERS IN PLANT SCIENCE 2022; 12:798992. [PMID: 35095970 PMCID: PMC8792611 DOI: 10.3389/fpls.2021.798992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Mucilage is a gelatinous high-molecular-weight substance produced by almost all plants, serving numerous functions for plant and soil. To date, research has mainly focused on hydraulic and physical functions of mucilage in the rhizosphere. Studies on the relevance of mucilage as a microbial habitat are scarce. Extracellular polymeric substances (EPS) are similarly gelatinous high-molecular-weight substances produced by microorganisms. EPS support the establishment of microbial assemblages in soils, mainly through providing a moist environment, a protective barrier, and serving as carbon and nutrient sources. We propose that mucilage shares physical and chemical properties with EPS, functioning similarly as a biofilm matrix covering a large extent of the rhizosphere. Our analyses found no evidence of consistent differences in viscosity and surface tension between EPS and mucilage, these being important physical properties. With regard to chemical composition, polysaccharide, protein, neutral monosaccharide, and uronic acid composition also showed no consistent differences between these biogels. Our analyses and literature review suggest that all major functions known for EPS and required for biofilm formation are also provided by mucilage, offering a protected habitat optimized for nutrient mobilization. Mucilage enables high rhizo-microbial abundance and activity by functioning as carbon and nutrient source. We suggest that the role of mucilage as a biofilm matrix has been underestimated, and should be considered in conceptual models of the rhizosphere.
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Affiliation(s)
- Meisam Nazari
- Division of Biogeochemistry of Agroecosystems, Georg-August University of Göttingen, Göttingen, Germany
| | - Samuel Bickel
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland
| | - Pascal Benard
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland
| | - Kyle Mason-Jones
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Andrea Carminati
- Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland
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A novel phage indirectly regulates diatom growth by infecting diatom-associated biofilm-forming bacterium. Appl Environ Microbiol 2022; 88:e0213821. [PMID: 35020448 DOI: 10.1128/aem.02138-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Algae and heterotrophic bacteria have close and intricate interactions, which are regulated by multiple factors in the natural environment. Phages are the major factor determining bacterial mortality. However, their impacts on the algae-associated bacteria and thus on the algae-bacteria interactions are poorly understood. Here, we obtained a diatom-associated bacterium Stappia indica SNL01 that could form biofilm and had an inhibitory effect on the growth of diatom Thalassiosira pseudonana. Meanwhile, the phage SI01 with a double-stranded circular DNA genome (44,247 bp) infecting S. indica SNL01 was isolated. Phylogenetic analysis revealed that phage SI01 represents a novel member of the Podoviridae family. The phage contained multiple lysis genes encoding for cell wall lysing muramidase and spore cortex lysing SleB, as well as depolymerase-like tail spike protein. By lysing the host bacterium and inhibiting the formation of biofilm, this phage could indirectly promote the growth of the diatom. Our results shed new insights into how phages indirectly regulate algal growth by infecting bacteria closely associated with algae or in the phycosphere. IMPORTANCE The impact of phage infection on the algae-bacteria relationship in the ocean is poorly understood. Here, a novel phage infecting the diatom-associated bacterium Stappia indica SNL01 was isolated. This bacterium could form biofilm and had a negative effect on diatom growth. We revealed that this phage contained multiple lysis genes and could inhibit the formation of bacterial biofilm, thus indirectly promoting diatom growth. This study implicates that phages are not only important regulators of bacteria but also have substantial indirect effects on algae as well as the algae-bacteria relationship.
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Roychoudhury T, Ray B, Seal A. Metabolically dependent consortia in biofilm: A new horizon for green agriculture. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2021.102256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kosina SM, Rademacher P, Wetmore KM, de Raad M, Zemla M, Zane GM, Zulovich JJ, Chakraborty R, Bowen BP, Wall JD, Auer M, Arkin AP, Deutschbauer AM, Northen TR. Biofilm Interaction Mapping and Analysis (BIMA) of Interspecific Interactions in Pseudomonas Co-culture Biofilms. Front Microbiol 2021; 12:757856. [PMID: 34956122 PMCID: PMC8696352 DOI: 10.3389/fmicb.2021.757856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/04/2021] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas species are ubiquitous in nature and include numerous medically, agriculturally and technologically beneficial strains of which the interspecific interactions are of great interest for biotechnologies. Specifically, co-cultures containing Pseudomonas stutzeri have been used for bioremediation, biocontrol, aquaculture management and wastewater denitrification. Furthermore, the use of P. stutzeri biofilms, in combination with consortia-based approaches, may offer advantages for these processes. Understanding the interspecific interaction within biofilm co-cultures or consortia provides a means for improvement of current technologies. However, the investigation of biofilm-based consortia has been limited. We present an adaptable and scalable method for the analysis of macroscopic interactions (colony morphology, inhibition, and invasion) between colony-forming bacterial strains using an automated printing method followed by analysis of the genes and metabolites involved in the interactions. Using Biofilm Interaction Mapping and Analysis (BIMA), these interactions were investigated between P. stutzeri strain RCH2, a denitrifier isolated from chromium (VI) contaminated soil, and 13 other species of pseudomonas isolated from non-contaminated soil. One interaction partner, Pseudomonas fluorescens N1B4 was selected for mutant fitness profiling of a DNA-barcoded mutant library; with this approach four genes of importance were identified and the effects on interactions were evaluated with deletion mutants and mass spectrometry based metabolomics.
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Affiliation(s)
- Suzanne M. Kosina
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Peter Rademacher
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Kelly M. Wetmore
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Markus de Raad
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Marcin Zemla
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Grant M. Zane
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
| | | | - Romy Chakraborty
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Benjamin P. Bowen
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Lawrence Berkeley National Laboratory, Joint Genome Institute, Berkeley, CA, United States
| | - Judy D. Wall
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
| | - Manfred Auer
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Adam P. Arkin
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Adam M. Deutschbauer
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Trent R. Northen
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Lawrence Berkeley National Laboratory, Joint Genome Institute, Berkeley, CA, United States
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35
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Diazotrophic Behaviour in a Non-Sterile Bioreactor: The Effect of O2-Availability. Processes (Basel) 2021. [DOI: 10.3390/pr9112039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The behaviour of a locally isolated diazotrophic consortium was investigated with the prospect of agricultural applications. A repeatable culture was obtained in a non-sterile bioreactor. Metagenomic analysis indicated Chryseobacterium ssp. and Flavobacterium ssp. were the dominant species, making up approximately 50% of the microbial community. The oxygen supply was varied and mass-transfer limited growth was attained under all experimental conditions. Negligible amounts of aqueous metabolites were formed, indicating a high selectivity towards biomass production. High oxygen availability resulted in decreased growth efficiencies i.e., the specific energy requirements for biomass synthesis. This was attributed to reduced electron transport chain efficiencies and nitrogenase protection mechanisms. Mass and energy balances indicated that sessile biomass with a high C:N served as a carbon sink. The most efficient growth was measured at an aeration feed composition of 21% oxygen and 79% nitrogen. The study presents one of the only known investigations of operational conditions on diazotrophic growth in a non-sterile bioreactor. In addition, it provides a strong foundation for the development of a Biological Nitrogen Fixation process with scaling potential.
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36
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Liu X, Liu Y, Wang Y, Wang D, Johnson KS, Xie Z. The Hypoxia-Associated Localization of Chemotaxis Protein CheZ in Azorhizorbium caulinodans. Front Microbiol 2021; 12:731419. [PMID: 34737727 PMCID: PMC8563088 DOI: 10.3389/fmicb.2021.731419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 09/22/2021] [Indexed: 11/15/2022] Open
Abstract
Spatial organization of chemotactic proteins is important for cooperative response to external stimuli. However, factors affecting the localization dynamics of chemotaxis proteins are less studied. According to some reports, the polar localization of chemotaxis system I is induced by hypoxia and starvation in Vibrio cholerae. However, in V. cholerae, the chemotaxis system I is not involved in flagellum-mediated chemotaxis, and it may play other alternative cellular functions. In this study, we found that the polar localization of CheZ, a phosphatase regulating chemotactic movement in Azorhizobium caulinodans ORS571, can also be affected by hypoxia and cellular energy-status. The conserved phosphatase active site D165 and the C-terminus of CheZ are essential for the energy-related localization, indicating a cross link between hypoxia-related localization changes and phosphatase activity of CheZ. Furthermore, three of five Aer-like chemoreceptors containing PAS domains participate in the cellular localization of CheZ. In contrast to carbon starvation, free-living nitrogen fixation can alleviate the role of nitrogen limitation and hypoxia on polar localization of CheZ. These results showed that the localization changes induced by hypoxia might be a strategy for bacteria to adapt to complex environment.
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Affiliation(s)
- Xiaolin Liu
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Yanan Liu
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Yixuan Wang
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Dandan Wang
- National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment of Shandong Agricultural University, Taian, China
| | - Kevin Scot Johnson
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Zhihong Xie
- National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment of Shandong Agricultural University, Taian, China
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Sierra Cacho D, Zamorano Sánchez DS, Xiqui-Vázquez ML, Viruega Góngora VI, Ramírez-Mata A, Baca BE. CdgC, a Cyclic-di-GMP Diguanylate Cyclase of Azospirillum baldaniorum Is Involved in Internalization to Wheat Roots. FRONTIERS IN PLANT SCIENCE 2021; 12:748393. [PMID: 34745182 PMCID: PMC8564387 DOI: 10.3389/fpls.2021.748393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
Azospirillum baldaniorum is a plant growth-promoting rhizobacterium (PGPR) capable of fixing nitrogen, the synthesis of several phytohormones including indole-acetic acid, and induction of plant defenses against phytopathogens. To establish a successful and prolonged bacteria-plant interaction, A. baldaniorum can form biofilms, bacterial communities embedded in a self-made matrix formed by extracellular polymeric substances which provide favorable conditions for survival. A key modulator of biofilm formation is the second messenger bis-(3'-5')-cyclic-dimeric-GMP (c-di-GMP), which is synthesized by diguanylate cyclases (DGC) and degraded by specific phosphodiesterases. In this study, we analyzed the contribution of a previously uncharacterized diguanylate cyclase designated CdgC, to biofilm formation and bacterial-plant interaction dynamics. We showed that CdgC is capable of altering c-di-GMP levels in a heterologous host, strongly supporting its function as a DGC. The deletion of cdgC resulted in alterations in the three-dimensional structure of biofilms in a nitrogen-source dependent manner. CdgC was required for optimal colonization of wheat roots. Since we also observed that CdgC played an important role in exopolysaccharide production, we propose that this signaling protein activates a physiological response that results in the strong attachment of bacteria to the roots, ultimately contributing to an optimal bacterium-plant interaction. Our results demonstrate that the ubiquitous second messenger c-di-GMP is a key factor in promoting plant colonization by the PGPR A. baldaniorum by allowing proficient internalization in wheat roots. Understanding the molecular basis of PGPR-plant interactions will enable the design of better biotechnological strategies of agro-industrial interest.
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Affiliation(s)
- Daniel Sierra Cacho
- Centro de Investigaciones en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, Mexico
| | - David S. Zamorano Sánchez
- Programa de Biología de Sistemas y Biología Sintética, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Maria Luisa Xiqui-Vázquez
- Centro de Investigaciones en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, Mexico
| | - Víctor Iván Viruega Góngora
- Centro de Investigaciones en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, Mexico
| | - Alberto Ramírez-Mata
- Centro de Investigaciones en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, Mexico
| | - Beatriz E. Baca
- Centro de Investigaciones en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, Mexico
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Evans AG, Temiz LA, Bangash SJ. A case study of phantosmia cured by antibiotic treatment of an intranasal Pseudomonas stutzeri infection. Braz J Otorhinolaryngol 2021; 88 Suppl 5:S203-S206. [PMID: 34756556 PMCID: PMC9801032 DOI: 10.1016/j.bjorl.2021.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 07/25/2021] [Accepted: 08/31/2021] [Indexed: 01/03/2023] Open
Affiliation(s)
- Adam G. Evans
- Meharry Medical College, Nashville, TN, USA,MOHS Surgery and Dermatology Center, Elgin, IL, USA,Corresponding author at: Meharry Medical College, Nashville, TN, USA.
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Evstigneeva SS, Telesheva EM, Mokeev DI, Borisov IV, Petrova LP, Shelud’ko AV. Response of Bacteria to Mechanical Stimuli. Microbiology (Reading) 2021. [DOI: 10.1134/s0026261721050052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Abstract—
Bacteria adapt rapidly to changes in ambient conditions, constantly inspecting their surroundings by means of their sensor systems. These systems are often thought to respond only to signals of a chemical nature. Yet, bacteria are often affected by mechanical forces, e.g., during transition from planktonic to sessile state. Mechanical stimuli, however, have seldom been considered as the signals bacteria can sense and respond to. Nonetheless, bacteria perceive mechanical stimuli, generate signals, and develop responses. This review analyzes the information on the way bacteria respond to mechanical stimuli and outlines how bacteria convert incoming signals into appropriate responses.
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40
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Wongbunmak A, Panthongkham Y, Suphantharika M, Pongtharangkul T. A fixed-film bioscrubber of Microbacterium esteraromaticum SBS1-7 for toluene/styrene biodegradation. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126287. [PMID: 34126384 DOI: 10.1016/j.jhazmat.2021.126287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/22/2021] [Accepted: 05/30/2021] [Indexed: 06/12/2023]
Abstract
In the present study, a fixed-film bioscrubber (FFBS) of BTEX-degrading bacterium Microbacterium esteraromaticum SBS1-7 with 'AQUAPOROUSGEL® or APG' supporting material was continuously fed with toluene- or styrene-contaminated gas stream for 172 days. Response Surface Methodology (RSM) was used to optimize the biofilm formation on APG as well as the toluene biodegradation in mineral salt medium (MM). The results suggested that 1000 ppm of yeast extract (YE) was necessary for biofilm formation of SBS1-7. The optimized combination of YE and toluene concentration exhibiting the highest biofilm formation and toluene removal was further employed in an up-scale FFBS operation. The maximum Elimination Capacity (ECmax) of 203 g·m-3·h-1 was obtained at the toluene Inlet Loading Rate (ILR) of 295 g·m-3·h-1. FFBS of SBS1-7 was able to withstand a 5-day shutdown and required only 24 h to recover. Moreover, when the inlet Volatile Organic Compound was shifted to styrene, FFBS required only 24 h for adaptation and the system was able to efficiently remove ~95% of styrene after that. Finally, the performance of the bioscrubber when operated in 2 different modes of operation (FFBS vs Biotricking Filter or BTF) were compared. This study evidently demonstrated the robustness and stability of FFBS with M. esteraromaticum SBS1-7.
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Affiliation(s)
- Akanit Wongbunmak
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Yanisa Panthongkham
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Manop Suphantharika
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
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Du C, Huo X, Gu H, Wu D, Hu Y. Acid resistance system CadBA is implicated in acid tolerance and biofilm formation and is identified as a new virulence factor of Edwardsiella tarda. Vet Res 2021; 52:117. [PMID: 34521475 PMCID: PMC8438976 DOI: 10.1186/s13567-021-00987-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/27/2021] [Indexed: 11/10/2022] Open
Abstract
Edwardsiella tarda is a facultative intracellular pathogen in humans and animals. The Gram-negative bacterium is widely considered a potentially important bacterial pathogen. Adaptation to acid stress is important for the transmission of intestinal microbes, so the acid-resistance (AR) system is essential. However, the AR systems of E. tarda are totally unknown. In this study, a lysine-dependent acid resistance (LDAR) system in E. tarda, CadBA, was characterized and identified. CadB is a membrane protein and shares high homology with the lysine/cadaverine antiporter. CadA contains a PLP-binding core domain and a pyridoxal phosphate-binding motif. It shares high homology with lysine decarboxylase. cadB and cadA are co-transcribed under one operon. To study the function of the cadBA operon, isogenic cadA, cadB and cadBA deletion mutant strains TX01ΔcadA, TX01ΔcadB and TX01ΔcadBA were constructed. When cultured under normal conditions, the wild type strain and three mutants exhibited the same growth performance. However, when cultured under acid conditions, the growth of three mutants, especially TX01ΔcadA, were obviously retarded, compared to the wild strain TX01, which indicates the important involvement of the cadBA operon in acid resistance. The deletion of cadB or cadA, especially cadBA, significantly attenuated bacterial activity of lysine decarboxylase, suggesting the vital participation of cadBA operon in lysine metabolism, which is closely related to acid resistance. The mutations of cadBA operon enhanced bacterial biofilm formation, especially under acid conditions. The deletions of the cadBA operon reduced bacterial adhesion and invasion to Hela cells. Consistently, the deficiency of cadBA operon abated bacterial survival and replication in macrophages, and decreased bacterial dissemination in fish tissues. Our results also show that the expression of cadBA operon and regulator cadC were up-regulated upon acid stress, and CadC rigorously regulated the expression of cadBA operon, especially under acid conditions. These findings demonstrate that the AR CadBA system was a requisite for the resistance of E. tarda against acid stress, and played a critical role in bacterial infection of host cells and in host tissues. This is the first study about the acid resistance system of E. tarda and provides new insights into the acid-resistance mechanism and pathogenesis of E. tarda.
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Affiliation(s)
- Chunmei Du
- College of Basic Medicine, Jiamusi University, 154007, Jiamusi, China.,Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, 571101, Haikou, China.,College of Life Science, Jiamusi University, 154007, Jiamusi, China
| | - Xiaoping Huo
- Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, 571101, Haikou, China.,College of Life Science, Jiamusi University, 154007, Jiamusi, China
| | - Hanjie Gu
- Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, 571101, Haikou, China.,Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-Resources, 571101, Haikou, China
| | - Dongmei Wu
- College of Basic Medicine, Jiamusi University, 154007, Jiamusi, China. .,Heilongjiang Provincial Key Laboratory of New Drug Development and Evaluation of the Efficacy of Toxicology, 154007, Jiamusi, China.
| | - Yonghua Hu
- Institute of Tropical Bioscience and Biotechnology, Hainan Academy of Tropical Agricultural Resource, CATAS, 571101, Haikou, China. .,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), 266071, Qingdao, China. .,College of Life Science, Jiamusi University, 154007, Jiamusi, China. .,Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-Resources, 571101, Haikou, China.
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Simunović V. Genomic and molecular evidence reveals novel pathways associated with cell surface polysaccharides in bacteria. FEMS Microbiol Ecol 2021; 97:6355432. [PMID: 34415013 DOI: 10.1093/femsec/fiab119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 08/18/2021] [Indexed: 11/13/2022] Open
Abstract
Amino acid (acyl carrier protein) ligases (AALs) are a relatively new family of bacterial amino acid adenylating enzymes with unknown function(s). Here, genomic enzymology tools that employ sequence similarity networks and genome context analyses were used to hypothesize the metabolic function(s) of AALs. In over 50% of species, aal and its cognate acyl carrier protein (acp) genes, along with three more genes, formed a highly conserved AAL cassette. AAL cassettes were strongly associated with surface polysaccharide gene clusters in Proteobacteria and Actinobacteria, yet were prevalent among soil and rhizosphere-associated α- and β-Proteobacteria, including symbiotic α- and β-rhizobia and some Mycolata. Based on these associations, AAL cassettes were proposed to encode a noncanonical Acp-dependent polysaccharide modification route. Genomic-inferred predictions were substantiated by published experimental evidence, revealing a role for AAL cassettes in biosynthesis of biofilm-forming exopolysaccharide in pathogenic Burkholderia and expression of aal and acp genes in nitrogen-fixing Rhizobium bacteroids. Aal and acp genes were associated with dltBD-like homologs that modify cell wall teichoic acids with d-alanine, including in Paenibacillus and certain other bacteria. Characterization of pathways that involve AAL and Acp may lead to developing new plant and human disease-controlling agents as well as strains with improved nitrogen fixation capacity.
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Li W, Liu M, Siddique MS, Graham N, Yu W. Contribution of bacterial extracellular polymeric substances (EPS) in surface water purification. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 280:116998. [PMID: 33780840 DOI: 10.1016/j.envpol.2021.116998] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
Naturally present aquatic microorganisms play an important role in water purification systems, such as the self-purification of surface waters. In this study, two water sources representing polluted surface water (Olympic Green; OG) and unpolluted surface water (Jingmi river; JM), were used to explore the self-purification of surface water by bacteria under different environmental conditions. The dominant bacterial community of OG and JM waters (both are Firmicutes and Proteobacteria) were isolated, cultured, and then used to carry out flocculation tests. Results showed that the flocculation ability of the dominant bacteria and extracellular polymeric substances (EPS) obtained from OG isolation was significantly greater than that from JM. Further examination illustrated that the main components of EPS were polysaccharides, which played an important role in improving the flocculation ability of bacteria. EPS from dominant cultural bacteria strains (OG1 and JM3) isolated from the two different sources lacked hydrophilic groups (e.g. COOH) and had a networked structure which are the main reasons to enhance the flocculation ability. The bacterial diversity and redundancy analysis (RDA) results also showed that microbial community composition is determined by water quality (SS, TOC, and NH4+), and different Bacteroidetes, Actinobacteria and Proteobacteria community structures can improve the water body's ability to remove environmental pollutants (such as SS, humic acid and fulvic acid). These findings provide new information showing how bacterial communities change with environmental factors while maintaining the purity of surface water.
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Affiliation(s)
- Weihua Li
- State Key Laboratory of Environmental Aquatic Chemistry, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China.
| | - Mengjie Liu
- State Key Laboratory of Environmental Aquatic Chemistry, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China
| | - Muhammad Saboor Siddique
- State Key Laboratory of Environmental Aquatic Chemistry, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China; University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Nigel Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom.
| | - Wenzheng Yu
- State Key Laboratory of Environmental Aquatic Chemistry, Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China.
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A regulatory network involving Rpo, Gac and Rsm for nitrogen-fixing biofilm formation by Pseudomonas stutzeri. NPJ Biofilms Microbiomes 2021; 7:54. [PMID: 34210981 PMCID: PMC8249394 DOI: 10.1038/s41522-021-00230-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/16/2021] [Indexed: 02/06/2023] Open
Abstract
Biofilm and nitrogen fixation are two competitive strategies used by many plant-associated bacteria; however, the mechanisms underlying the formation of nitrogen-fixing biofilms remain largely unknown. Here, we examined the roles of multiple signalling systems in the regulation of biofilm formation by root-associated diazotrophic P. stutzeri A1501. Physiological analysis, construction of mutant strains and microscale thermophoresis experiments showed that RpoN is a regulatory hub coupling nitrogen fixation and biofilm formation by directly activating the transcription of pslA, a major gene involved in the synthesis of the Psl exopolysaccharide component of the biofilm matrix and nifA, the transcriptional activator of nif gene expression. Genetic complementation studies and determination of the copy number of transcripts by droplet digital PCR confirmed that the regulatory ncRNA RsmZ serves as a signal amplifier to trigger biofilm formation by sequestering the translational repressor protein RsmA away from pslA and sadC mRNAs, the latter of which encodes a diguanylate cyclase that synthesises c-di-GMP. Moreover, RpoS exerts a braking effect on biofilm formation by transcriptionally downregulating RsmZ expression, while RpoS expression is repressed posttranscriptionally by RsmA. These findings provide mechanistic insights into how the Rpo/Gac/Rsm regulatory networks fine-tune nitrogen-fixing biofilm formation in response to the availability of nutrients.
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Lyu D, Zajonc J, Pagé A, Tanney CAS, Shah A, Monjezi N, Msimbira LA, Antar M, Nazari M, Backer R, Smith DL. Plant Holobiont Theory: The Phytomicrobiome Plays a Central Role in Evolution and Success. Microorganisms 2021; 9:675. [PMID: 33805166 PMCID: PMC8064057 DOI: 10.3390/microorganisms9040675] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/20/2021] [Accepted: 03/23/2021] [Indexed: 12/15/2022] Open
Abstract
Under natural conditions, plants are always associated with a well-orchestrated community of microbes-the phytomicrobiome. The nature and degree of microbial effect on the plant host can be positive, neutral, or negative, and depends largely on the environment. The phytomicrobiome is integral for plant growth and function; microbes play a key role in plant nutrient acquisition, biotic and abiotic stress management, physiology regulation through microbe-to-plant signals, and growth regulation via the production of phytohormones. Relationships between the plant and phytomicrobiome members vary in intimacy, ranging from casual associations between roots and the rhizosphere microbial community, to endophytes that live between plant cells, to the endosymbiosis of microbes by the plant cell resulting in mitochondria and chloroplasts. If we consider these key organelles to also be members of the phytomicrobiome, how do we distinguish between the two? If we accept the mitochondria and chloroplasts as both members of the phytomicrobiome and the plant (entrained microbes), the influence of microbes on the evolution of plants becomes so profound that without microbes, the concept of the "plant" is not viable. This paper argues that the holobiont concept should take greater precedence in the plant sciences when referring to a host and its associated microbial community. The inclusivity of this concept accounts for the ambiguous nature of the entrained microbes and the wide range of functions played by the phytomicrobiome in plant holobiont homeostasis.
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Affiliation(s)
- Dongmei Lyu
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Jonathan Zajonc
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Antoine Pagé
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
- National Research Council Canada, Aquatic and Crop Resource Development (ACRD), Montréal, QC H4P 2R2, Canada
| | - Cailun A. S. Tanney
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Ateeq Shah
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Nadia Monjezi
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Levini A. Msimbira
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Mohammed Antar
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Mahtab Nazari
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Rachel Backer
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
| | - Donald L. Smith
- Department of Plant Science, Macdonald Campus, McGill University, Montréal, QC H9X 3V9, Canada; (D.L.); (J.Z.); (A.P.); (C.A.S.T.); (A.S.); (N.M.); (L.A.M.); (M.A.); (M.N.); (R.B.)
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Rather MA, Gupta K, Bardhan P, Borah M, Sarkar A, Eldiehy KSH, Bhuyan S, Mandal M. Microbial biofilm: A matter of grave concern for human health and food industry. J Basic Microbiol 2021; 61:380-395. [PMID: 33615511 DOI: 10.1002/jobm.202000678] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/27/2021] [Accepted: 02/06/2021] [Indexed: 12/15/2022]
Abstract
Pathogenic microorganisms have adapted different strategies during the course of time to invade host defense mechanisms and overcome the effect of potent antibiotics. The formation of biofilm on both biotic and abiotic surfaces by microorganisms is one such strategy to resist and survive even in presence of antibiotics and other adverse environmental conditions. Biofilm is a safe home of microorganisms embedded within self-produced extracellular polymeric substances comprising of polysaccharides, extracellular proteins, nucleic acid, and water. It is because of this adaptation strategy that pathogenic microorganisms are taking a heavy toll on the health and life of organisms. In this review, we discuss the colonization of pathogenic microorganisms on tissues and medically implanted devices in human beings. We also focus on food spoilage, disease outbreaks, biofilm-associated deaths, burden on economy, and other major concerns of biofilm-forming pathogenic microorganisms in food industries like dairy, poultry, ready-to-eat food, meat, and aquaculture.
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Affiliation(s)
- Muzamil A Rather
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Kuldeep Gupta
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Pritam Bardhan
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Munmi Borah
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Anupama Sarkar
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Khalifa S H Eldiehy
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India.,Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Assiut, Egypt
| | - Shuvam Bhuyan
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Manabendra Mandal
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
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Mitter EK, Tosi M, Obregón D, Dunfield KE, Germida JJ. Rethinking Crop Nutrition in Times of Modern Microbiology: Innovative Biofertilizer Technologies. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021. [DOI: 10.3389/fsufs.2021.606815] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Global population growth poses a threat to food security in an era of increased ecosystem degradation, climate change, soil erosion, and biodiversity loss. In this context, harnessing naturally-occurring processes such as those provided by soil and plant-associated microorganisms presents a promising strategy to reduce dependency on agrochemicals. Biofertilizers are living microbes that enhance plant nutrition by either by mobilizing or increasing nutrient availability in soils. Various microbial taxa including beneficial bacteria and fungi are currently used as biofertilizers, as they successfully colonize the rhizosphere, rhizoplane or root interior. Despite their great potential to improve soil fertility, biofertilizers have yet to replace conventional chemical fertilizers in commercial agriculture. In the last 10 years, multi-omics studies have made a significant step forward in understanding the drivers, roles, processes, and mechanisms in the plant microbiome. However, translating this knowledge on microbiome functions in order to capitalize on plant nutrition in agroecosystems still remains a challenge. Here, we address the key factors limiting successful field applications of biofertilizers and suggest potential solutions based on emerging strategies for product development. Finally, we discuss the importance of biosafety guidelines and propose new avenues of research for biofertilizer development.
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Singh P, Singh RK, Guo DJ, Sharma A, Singh RN, Li DP, Malviya MK, Song XP, Lakshmanan P, Yang LT, Li YR. Whole Genome Analysis of Sugarcane Root-Associated Endophyte Pseudomonas aeruginosa B18-A Plant Growth-Promoting Bacterium With Antagonistic Potential Against Sporisorium scitamineum. Front Microbiol 2021; 12:628376. [PMID: 33613496 PMCID: PMC7894208 DOI: 10.3389/fmicb.2021.628376] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/12/2021] [Indexed: 12/20/2022] Open
Abstract
Sugarcane smut is a significant fungal disease that causes a major loss in sugar yield and quality. In this study, we isolated an endophytic strain B18 from a sugarcane root, which showed plant growth-promotion, hydrolytic enzyme production, antifungal activity against sugarcane pathogens (Sporisorium scitamineum, Ceratocystis paradoxa, Fusarium verticillioides), and the presence of nifH, acdS, and antibiotic genes (hcn, prn, and phCA) under in vitro conditions. BIOLOG(R) phenotypic profiling of B18 established its ability to use various carbon and nitrogen sources and tolerate a range of pH and osmotic and temperature stresses. Whole-genome analysis of B18, identified as Pseudomonas aeruginosa, showed that it consists of a single circular chromosome of 6,490,014 bp with 66.33% GC content. Genome annotation has identified 5,919 protein-coding genes, and 65 tRNA, and 12 rRNA genes. The P. aeruginosa B18 genome encodes genes related to ethylene, nitrogen (nifU, norBCDERQ, gltBDPS, and aatJMPQ), and phosphate (pstABCS and phoBDHRU) metabolism and produce indole-3-acetic acid and siderophores. This also includes genes encoding hydrolases and oxidoreductases, those associated with biocontrol mechanisms (hcnABC, phzA_B, phzDEFGMS, and pchA), colonization (minCDE and lysC), and biofilm formation (efp, hfq, flgBCDEFGHI, and motAB), and those associated with metabolism of secondary metabolites. Collectively, these results suggest a role for P. aeruginosa B18 in plant growth enhancement and biocontrol mechanisms. The P. aeruginosa B18 strain was found to be an efficient colonizer in sugarcane; it can improve growth through modulation of plant hormone production and enhanced host-plant resistance to smut pathogen S. scitamineum in a smut-susceptible sugarcane variety (Yacheng71-374). These biocontrol and plant growth promotion properties of P. aeruginosa B18 area are discussed in this report.
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Affiliation(s)
- Pratiksha Singh
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, 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.,Guangxi Key Laboratory of Crop Genetic Improvement and Biotechnology, Nanning, China
| | - Rajesh Kumar Singh
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, 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.,Guangxi Key Laboratory of Crop Genetic Improvement and Biotechnology, Nanning, China
| | - Dao-Jun Guo
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, 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.,Guangxi Key Laboratory of Crop Genetic Improvement and Biotechnology, Nanning, China.,College of Agriculture, Guangxi University, Nanning, China
| | - Anjney Sharma
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, 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.,Guangxi Key Laboratory of Crop Genetic Improvement and Biotechnology, Nanning, China
| | | | - Dong-Ping Li
- Microbiology Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Mukesh K Malviya
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, 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.,Guangxi Key Laboratory of Crop Genetic Improvement and Biotechnology, Nanning, China
| | - Xiu-Peng Song
- Guangxi Key Laboratory of Crop Genetic Improvement and Biotechnology, Nanning, China
| | - Prakash Lakshmanan
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, 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 (CAGD), College of Resources and Environment, Southwest University, Chongqing, China.,Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD, Australia
| | - Li-Tao Yang
- Guangxi Key Laboratory of Crop Genetic Improvement and Biotechnology, Nanning, China.,College of Agriculture, Guangxi University, Nanning, China
| | - Yang-Rui Li
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture, 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.,Guangxi Key Laboratory of Crop Genetic Improvement and Biotechnology, Nanning, China.,College of Agriculture, Guangxi University, Nanning, China
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Bhatia R, Gulati D, Sethi G. Biofilms and nanoparticles: applications in agriculture. Folia Microbiol (Praha) 2021; 66:159-170. [PMID: 33528768 DOI: 10.1007/s12223-021-00851-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 01/04/2021] [Indexed: 02/04/2023]
Abstract
A profound need to explore eco-friendly methods to practice sustainable agriculture leads to the research and exploration of plant growth-promoting rhizobacteria (PGPRs). Biofilms are assemblages of microbial communities within a self-secreted exopolymeric matrix, adhering to different biotic and abiotic surfaces and performing a variety of desired and undesired functions. Biofilm formation by PGPRs is governed by effective root colonization of the host plant in providing plant growth promotion and stress management. Biofilms can also provide a suitable environment for the synthesis and entrapment of nanoparticles. Together, nanoparticles and PGPRs may contribute towards biocontrol and crop management. This review discusses the significance of biofilms in agriculture and their confluence with different types of nanoparticles for plant protection and improved crop production.
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Affiliation(s)
- Ranjana Bhatia
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India.
| | - Divij Gulati
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India
| | - Gavin Sethi
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India
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Effects of an EPS Biosynthesis Gene Cluster of Paenibacillus polymyxa WLY78 on Biofilm Formation and Nitrogen Fixation under Aerobic Conditions. Microorganisms 2021; 9:microorganisms9020289. [PMID: 33573330 PMCID: PMC7911366 DOI: 10.3390/microorganisms9020289] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/17/2022] Open
Abstract
Exopolysaccharides (EPS) are of high significance in bacterial biofilm formation. However, the effects of EPS cluster(s) on biofilm formation in Paenibacillus species are little known. In this study, we have shown that Paenibacillus polymyxa WLY78, a N2-fixing bacterium, can form biofilm. EPS is the major component of the extracellular matrix. The genome of P. polymyxa WLY78 contains two putative gene clusters (designated pep-1 cluster and pep-2 cluster). The pep-1 cluster is composed of 12 putative genes (pepO-lytR) co-located in a 13 kb region. The pep-2 cluster contains 17 putative genes (pepA-pepN) organized as an operon in a 20 kb region. Mutation analysis reveals that the pep-2 cluster is involved in EPS biosynthesis and biofilm formation. Disruption of the pep-2 cluster also leads to the enhancement of motility and change of the colony morphology. In contrast, disruption of the pep-1 cluster does not affect EPS synthesis or biofilm formation. More importantly, the biofilm allowed P. polymyxa WLY78 to fix nitrogen in aerobic conditions, suggesting that biofilm may provide a microaerobic environment for nitrogenase synthesis and activity.
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