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Schlechter RO, Kear EJ, Bernach M, Remus DM, Remus-Emsermann MNP. Metabolic resource overlap impacts competition among phyllosphere bacteria. THE ISME JOURNAL 2023; 17:1445-1454. [PMID: 37355740 PMCID: PMC10432529 DOI: 10.1038/s41396-023-01459-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 06/26/2023]
Abstract
The phyllosphere is densely colonised by microbial communities, despite sparse and heterogeneously distributed resources. The limitation of resources is expected to drive bacterial competition resulting in exclusion or coexistence based on fitness differences and resource overlap between individual colonisers. We studied the impact of resource competition by determining the effects of different bacterial colonisers on the growth of the model epiphyte Pantoea eucalypti 299R (Pe299R). Resource overlap was predicted based on genome-scale metabolic modelling. By combining results of metabolic modelling and pairwise competitions in the Arabidopsis thaliana phyllosphere and in vitro, we found that ten resources sufficed to explain fitness of Pe299R. An effect of both resource overlap and phylogenetic relationships was found on competition outcomes in vitro as well as in the phyllosphere. However, effects of resource competition were much weaker in the phyllosphere when compared to in vitro experiments. When investigating growth dynamics and reproductive success at the single-cell resolution, resource overlap and phylogenetic relationships are only weakly correlated with epiphytic Pe299R reproductive success, indicating that the leaf's spatial heterogeneity mitigates resource competition. Although the correlation is weak, the presence of competitors led to the development of Pe299R subpopulations that experienced different life histories and cell divisions. In some in planta competitions, Pe299R benefitted from the presence of epiphytes despite high resource overlap to the competitor strain suggesting other factors having stronger effects than resource competition. This study provides fundamental insights into how bacterial communities are shaped in heterogeneous environments and a framework to predict competition outcomes.
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Affiliation(s)
- Rudolf O Schlechter
- Institute of Microbiology and Dahlem Centre of Plant Sciences, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany.
- School of Biological Sciences, University of Canterbury, Christchurch, 8011, New Zealand.
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, 8011, New Zealand.
- Bioprotection Research Core, University of Canterbury, Christchurch, 8011, New Zealand.
| | - Evan J Kear
- School of Biological Sciences, University of Canterbury, Christchurch, 8011, New Zealand
| | - Michał Bernach
- Institute of Microbiology and Dahlem Centre of Plant Sciences, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany
- School of Biological Sciences, University of Canterbury, Christchurch, 8011, New Zealand
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, 8011, New Zealand
- Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, 8011, New Zealand
| | - Daniela M Remus
- Protein Science and Engineering, Callaghan Innovation, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Mitja N P Remus-Emsermann
- Institute of Microbiology and Dahlem Centre of Plant Sciences, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany.
- School of Biological Sciences, University of Canterbury, Christchurch, 8011, New Zealand.
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, 8011, New Zealand.
- Bioprotection Research Core, University of Canterbury, Christchurch, 8011, New Zealand.
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Tomassetti M, Garavaglia BS, Vranych CV, Gottig N, Ottado J, Gramajo H, Diacovich L. 3-methylcrotonyl Coenzyme A (CoA) carboxylase complex is involved in the Xanthomonas citri subsp. citri lifestyle during citrus infection. PLoS One 2018; 13:e0198414. [PMID: 29879157 PMCID: PMC5991677 DOI: 10.1371/journal.pone.0198414] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/19/2018] [Indexed: 01/15/2023] Open
Abstract
Citrus canker is a disease caused by the phytopathogen Xanthomonas citri subsp. citri (Xcc), bacterium which is unable to survive out of the host for extended periods of time. Once established inside the plant, the pathogen must compete for resources and evade the defenses of the host cell. However, a number of aspects of Xcc metabolic and nutritional state, during the epiphytic stage and at different phases of infection, are poorly characterized. The 3-methylcrotonyl-CoA carboxylase complex (MCC) is an essential enzyme for the catabolism of the branched-chain amino acid leucine, which prevents the accumulation of toxic intermediaries, facilitates the generation of branched chain fatty acids and/or provides energy to the cell. The MCC complexes belong to a group of acyl-CoA carboxylases (ACCase) enzymes dependent of biotin. In this work, we have identified two ORFs (XAC0263 and XAC0264) encoding for the α and β subunits of an acyl-CoA carboxylase complex from Xanthomonas and demonstrated that this enzyme has MCC activity both in vitro and in vivo. We also found that this MCC complex is conserved in a group of pathogenic gram negative bacteria. The generation and analysis of an Xcc mutant strain deficient in MCC showed less canker lesions in the interaction with the host plant, suggesting that the expression of these proteins is necessary for Xcc fitness during infection.
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Affiliation(s)
- Mauro Tomassetti
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Betiana S. Garavaglia
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Cecilia V. Vranych
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Natalia Gottig
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Jorgelina Ottado
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Hugo Gramajo
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Lautaro Diacovich
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
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Yang T, Wei Z, Friman V, Xu Y, Shen Q, Kowalchuk GA, Jousset A. Resource availability modulates biodiversity‐invasion relationships by altering competitive interactions. Environ Microbiol 2017; 19:2984-2991. [DOI: 10.1111/1462-2920.13708] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/13/2017] [Accepted: 02/17/2017] [Indexed: 12/23/2022]
Affiliation(s)
- Tianjie Yang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersJiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University210095Nanjing People's Republic of China
- Institute for Environmental Biology, Ecology & BiodiversityUtrecht UniversityPadualaan 8, 3584 CH Utrecht The Netherlands
| | - Zhong Wei
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersJiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University210095Nanjing People's Republic of China
| | | | - Yangchun Xu
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersJiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University210095Nanjing People's Republic of China
| | - Qirong Shen
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersJiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University210095Nanjing People's Republic of China
| | - George A. Kowalchuk
- Institute for Environmental Biology, Ecology & BiodiversityUtrecht UniversityPadualaan 8, 3584 CH Utrecht The Netherlands
| | - Alexandre Jousset
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic‐based FertilizersJiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University210095Nanjing People's Republic of China
- Institute for Environmental Biology, Ecology & BiodiversityUtrecht UniversityPadualaan 8, 3584 CH Utrecht The Netherlands
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Stockwell VO, Davis EW, Carey A, Shaffer BT, Mavrodi DV, Hassan KA, Hockett K, Thomashow LS, Paulsen IT, Loper JE. pA506, a conjugative plasmid of the plant epiphyte Pseudomonas fluorescens A506. Appl Environ Microbiol 2013; 79:5272-82. [PMID: 23811504 PMCID: PMC3753976 DOI: 10.1128/aem.01354-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/21/2013] [Indexed: 11/20/2022] Open
Abstract
Conjugative plasmids are known to facilitate the acquisition and dispersal of genes contributing to the fitness of Pseudomonas spp. Here, we report the characterization of pA506, the 57-kb conjugative plasmid of Pseudomonas fluorescens A506, a plant epiphyte used in the United States for the biological control of fire blight disease of pear and apple. Twenty-nine of the 67 open reading frames (ORFs) of pA506 have putative functions in conjugation, including a type IV secretion system related to that of MOBP6 family plasmids and a gene cluster for type IV pili. We demonstrate that pA506 is self-transmissible via conjugation between A506 and strains of Pseudomonas spp. or the Enterobacteriaceae. The origin of vegetative replication (oriV) of pA506 is typical of those in pPT23A family plasmids, which are present in many pathovars of Pseudomonas syringae, but pA506 lacks repA, a defining locus for pPT23A plasmids, and has a novel partitioning region. We selected a plasmid-cured derivative of A506 and compared it to the wild type to identify plasmid-encoded phenotypes. pA506 conferred UV resistance, presumably due to the plasmid-borne rulAB genes, but did not influence epiphytic fitness of A506 on pear or apple blossoms in the field. pA506 does not appear to confer resistance to antibiotics or other toxic elements. Based on the conjugative nature of pA506 and the large number of its genes that are shared with plasmids from diverse groups of environmental bacteria, the plasmid is likely to serve as a vehicle for genetic exchange between A506 and its coinhabitants on plant surfaces.
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Affiliation(s)
- Virginia O. Stockwell
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Edward W. Davis
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
- Agricultural Research Service, U.S. Department of Agriculture, Corvallis, Oregon, USA
| | - Alyssa Carey
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
- Agricultural Research Service, U.S. Department of Agriculture, Corvallis, Oregon, USA
| | - Brenda T. Shaffer
- Agricultural Research Service, U.S. Department of Agriculture, Corvallis, Oregon, USA
| | - Dmitri V. Mavrodi
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA
| | - Karl A. Hassan
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, Australia
| | - Kevin Hockett
- Agricultural Research Service, U.S. Department of Agriculture, Corvallis, Oregon, USA
| | - Linda S. Thomashow
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA
- Agricultural Research Service, U.S. Department of Agriculture, Pullman, Washington, USA
| | - Ian T. Paulsen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, Australia
| | - Joyce E. Loper
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
- Agricultural Research Service, U.S. Department of Agriculture, Corvallis, Oregon, USA
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Hagen MJ, Stockwell VO, Whistler CA, Johnson KB, Loper JE. Stress tolerance and environmental fitness of Pseudomonas fluorescens A506, which has a mutation in RpoS. PHYTOPATHOLOGY 2009; 99:679-688. [PMID: 19453226 DOI: 10.1094/phyto-99-6-0679] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Establishment of suppressive populations of bacterial biological control agents on aerial plant surfaces is a critical phase in biologically based management of floral diseases. Periodically, biocontrol agents encounter inhospitable conditions for growth on plants; consequently, tolerance of environmental stresses may contribute to their fitness. In many gram-negative bacteria, including strains of Pseudomonas spp., the capacity to survive environmental stresses is influenced by the stationary phase sigma factor RpoS. This study focused on the role of RpoS in stress response and epiphytic fitness of Pseudomonas fluorescens A506, a well-studied bacterial biological control agent. We detected a frameshift mutation in the rpoS of A506 and demonstrated that the mutation resulted in a truncated, nonfunctional RpoS. Using site-directed mutagenesis, we deleted a nucleotide from rpoS, which then encoded a full-length, functional RpoS. We compared the stress response and epiphytic fitness of A506 with derivative strains having the functional full-length RpoS or a disrupted, nonfunctional RpoS. RpoS had little effect on stress response of A506 and no consistent influence on epiphytic population size of A506 on pear or apple leaves or flowers. Although the capacity of strain A506 to withstand exposure to environmental stresses was similar to that of other fluorescent pseudomonads, this capacity was largely independent of rpoS.
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Affiliation(s)
- Mary J Hagen
- Department of Botany, Oregon State University, Corvallis 97331, USA
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Hert AP, Marutani M, Momol MT, Roberts PD, Olson SM, Jones JB. Suppression of the bacterial spot pathogen Xanthomonas euvesicatoria on tomato leaves by an attenuated mutant of Xanthomonas perforans. Appl Environ Microbiol 2009; 75:3323-30. [PMID: 19286785 PMCID: PMC2681633 DOI: 10.1128/aem.02399-08] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Accepted: 03/09/2009] [Indexed: 11/20/2022] Open
Abstract
A bacteriocin-producing strain of the bacterial spot of tomato plant pathogen, Xanthomonas perforans, with attenuated pathogenicity was deployed for biocontrol of a bacteriocin-sensitive strain of the genetically closely related bacterial spot of tomato plant pathogen, X. euvesicatoria. The attenuated mutant (91-118DeltaopgHDeltabcnB) of X. perforans was tested in leaf tissue and shown to significantly inhibit internal populations of the wild-type X. euvesicatoria strain although significantly less than the wild-type 91-118 strain, whereas in a phyllosphere inhibition assay, the mutant strain reduced epiphytic populations comparably to 91-118. Thus, the attenuated mutant limited the sensitive bacterium more efficiently on the leaf surface than inside the leaf. In field experiments, weekly application of 91-118DeltaopgHDeltabcnB significantly reduced X. euvesicatoria populations compared to the growers' standard control (copper hydroxide and mancozeb applied weekly and acibenzolar-S-methyl applied every 2 weeks). The biological control agent, 91-118DeltaopgHDeltabcnB, applied every 2 weeks also significantly reduced X. euvesicatoria populations in one season but was not significantly different from the growers' standard control. Potentially, attenuated pathogenic strains could be deployed as biological control agents in order to improve disease control of foliar plant pathogens.
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Affiliation(s)
- A P Hert
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
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McSpadden Gardener BB. Diversity and Ecology of Biocontrol Pseudomonas spp. in Agricultural Systems. PHYTOPATHOLOGY 2007; 97:221-226. [PMID: 18944378 DOI: 10.1094/phyto-97-2-0221] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT Diverse Pseudomonas spp. may act as biological controls of plant pathogens, but the ecology of those natural populations is not well understood. And, while biocontrol potential has been identified in multiple pseudomonad strains, the linkages between genotype and phenotype have yet to be fully delineated. However, intensive studies of one class of biocontrol strains, i.e., those that can produce 2,4-diacetylphloroglucionl (DAPG), have provided new insights into the diversity, distribution, and interactions of biocontrol pseudomonads. Those studies also laid the foundation for future research and development of pseudomonad-based biocontrol strategies. Over the past several years, numerous studies have also revealed that biocontrol pseudomonads are widely distributed in agricultural soils, and that multiple crop and soil factors can affect their abundance and activities. Recent work has shown that a variety of farm management practices that reduce soilborne disease pressure can also alter the rhizosphere abundance of DAPG producers in complex ways. Such studies provide support for the hypothesis of an ecological feedback mechanism whereby a native biocontrol population increase and subsequently reduce root disease severity following infection. It is well established that complex biological interactions can take place among bio-control pseudomonads, plant pathogens, their hosts, and other members of the microbial community. The net result of such interactions likely dilutes biocontrol efficacy at the field scale. Nonetheless, inoculation can be effective, and several successful applications of biocontrol pseudomonads have been developed. Future applications of microbial ecology research will hopefully improve the consistency and efficacy of bio-control mediated by Pseudomonas spp. Current applications and future opportunities for improving pseudomonad-based biological control are discussed.
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