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Poli N, Keel CJ, Garrido-Sanz D. Expanding the Pseudomonas diversity of the wheat rhizosphere: four novel species antagonizing fungal phytopathogens and with plant-beneficial properties. Front Microbiol 2024; 15:1440341. [PMID: 39077740 PMCID: PMC11284033 DOI: 10.3389/fmicb.2024.1440341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 07/01/2024] [Indexed: 07/31/2024] Open
Abstract
Plant-beneficial Pseudomonas bacteria hold the potential to be used as inoculants in agriculture to promote plant growth and health through various mechanisms. The discovery of new strains tailored to specific agricultural needs remains an open area of research. In this study, we report the isolation and characterization of four novel Pseudomonas species associated with the wheat rhizosphere. Comparative genomic analysis with all available Pseudomonas type strains revealed species-level differences, substantiated by both digital DNA-DNA hybridization and average nucleotide identity, underscoring their status as novel species. This was further validated by the phenotypic differences observed when compared to their closest relatives. Three of the novel species belong to the P. fluorescens species complex, with two representing a novel lineage in the Pseudomonas phylogeny. Functional genome annotation revealed the presence of specific features contributing to rhizosphere colonization, including flagella and components for biofilm formation. The novel species have the genetic potential to solubilize nutrients by acidifying the environment, releasing alkaline phosphatases and their metabolism of nitrogen species, indicating potential as biofertilizers. Additionally, the novel species possess traits that may facilitate direct promotion of plant growth through the modulation of the plant hormone balance, including the ACC deaminase enzyme and auxin metabolism. The presence of biosynthetic clusters for toxins such as hydrogen cyanide and non-ribosomal peptides suggests their ability to compete with other microorganisms, including plant pathogens. Direct inoculation of wheat roots significantly enhanced plant growth, with two strains doubling shoot biomass. Three of the strains effectively antagonized fungal phytopathogens (Thielaviopsis basicola, Fusarium oxysporum, and Botrytis cinerea), demonstrating their potential as biocontrol agents. Based on the observed genetic and phenotypic differences from closely related species, we propose the following names for the four novel species: Pseudomonas grandcourensis sp. nov., type strain DGS24T ( = DSM 117501T = CECT 31011T), Pseudomonas purpurea sp. nov., type strain DGS26T ( = DSM 117502T = CECT 31012T), Pseudomonas helvetica sp. nov., type strain DGS28T ( = DSM 117503T = CECT 31013T) and Pseudomonas aestiva sp. nov., type strain DGS32T ( = DSM 117504T = CECT 31014T).
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Affiliation(s)
| | - Christoph Joseph Keel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Daniel Garrido-Sanz
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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Fabian B, Foster C, Asher A, Hassan K, Paulsen I, Tetu S. Identifying the suite of genes central to swimming in the biocontrol bacterium Pseudomonas protegens Pf-5. Microb Genom 2024; 10:001212. [PMID: 38546328 PMCID: PMC11004494 DOI: 10.1099/mgen.0.001212] [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: 01/01/2024] [Accepted: 02/20/2024] [Indexed: 04/12/2024] Open
Abstract
Swimming motility is a key bacterial trait, important to success in many niches. Biocontrol bacteria, such as Pseudomonas protegens Pf-5, are increasingly used in agriculture to control crop diseases, where motility is important for colonization of the plant rhizosphere. Swimming motility typically involves a suite of flagella and chemotaxis genes, but the specific gene set employed for both regulation and biogenesis can differ substantially between organisms. Here we used transposon-directed insertion site sequencing (TraDIS), a genome-wide approach, to identify 249 genes involved in P. protegens Pf-5 swimming motility. In addition to the expected flagella and chemotaxis, we also identified a suite of additional genes important for swimming, including genes related to peptidoglycan turnover, O-antigen biosynthesis, cell division, signal transduction, c-di-GMP turnover and phosphate transport, and 27 conserved hypothetical proteins. Gene knockout mutants and TraDIS data suggest that defects in the Pst phosphate transport system lead to enhanced swimming motility. Overall, this study expands our knowledge of pseudomonad motility and highlights the utility of a TraDIS-based approach for analysing the functions of thousands of genes. This work sets a foundation for understanding how swimming motility may be related to the inconsistency in biocontrol bacteria performance in the field.
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Affiliation(s)
- B.K. Fabian
- School of Natural Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | - C. Foster
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - A. Asher
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - K.A. Hassan
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
- School of Environmental and Life Sciences, University of Newcastle, Newcastle, Australia
| | - I.T. Paulsen
- School of Natural Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | - S.G. Tetu
- School of Natural Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
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3
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Blanco-Romero E, Garrido-Sanz D, Durán D, Rybtke M, Tolker-Nielsen T, Redondo-Nieto M, Rivilla R, Martín M. Role of extracellular matrix components in biofilm formation and adaptation of Pseudomonas ogarae F113 to the rhizosphere environment. Front Microbiol 2024; 15:1341728. [PMID: 38333580 PMCID: PMC10850567 DOI: 10.3389/fmicb.2024.1341728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 01/11/2024] [Indexed: 02/10/2024] Open
Abstract
Regulating the transition of bacteria from motile to sessile lifestyles is crucial for their ability to compete effectively in the rhizosphere environment. Pseudomonas are known to rely on extracellular matrix (ECM) components for microcolony and biofilm formation, allowing them to adapt to a sessile lifestyle. Pseudomonas ogarae F113 possesses eight gene clusters responsible for the production of ECM components. These gene clusters are tightly regulated by AmrZ, a major transcriptional regulator that influences the cellular levels of c-di-GMP. The AmrZ-mediated transcriptional regulation of ECM components is primarily mediated by the signaling molecule c-di-GMP and the flagella master regulator FleQ. To investigate the functional role of these ECM components in P. ogarae F113, we performed phenotypic analyses using mutants in genes encoding these ECM components. These analyses included assessments of colony morphology, dye-staining, static attachment to abiotic surfaces, dynamic biofilm formation on abiotic surfaces, swimming motility, and competitive colonization assays of the rhizosphere. Our results revealed that alginate and PNAG polysaccharides, along with PsmE and the fimbrial low molecular weight protein/tight adherence (Flp/Tad) pilus, are the major ECM components contributing to biofilm formation. Additionally, we found that the majority of these components and MapA are needed for a competitive colonization of the rhizosphere in P. ogarae F113.
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Affiliation(s)
- Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Morten Rybtke
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
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Vacheron J, Heiman CM, Garneau JR, Kupferschmied P, de Jonge R, Garrido-Sanz D, Keel C. Molecular and evolutionary basis of O-antigenic polysaccharide-driven phage sensitivity in environmental pseudomonads. Microbiol Spectr 2023; 11:e0204923. [PMID: 37800913 PMCID: PMC10715155 DOI: 10.1128/spectrum.02049-23] [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: 05/16/2023] [Accepted: 08/16/2023] [Indexed: 10/07/2023] Open
Abstract
IMPORTANCE The application of plant-beneficial microorganisms to protect crop plants is a promising alternative to the usage of chemicals. However, biocontrol research often faces difficulties in implementing this approach due to the inconsistency of the bacterial inoculant to establish itself within the root microbiome. Beneficial bacterial inoculants can be decimated by the presence of their natural predators, notably bacteriophages (also called phages). Thus, it is important to gain knowledge regarding the mechanisms behind phage-bacteria interactions to overcome this challenge. Here, we evidence that the major long O-antigenic polysaccharide (O-PS, O-antigen) of the widely used model plant-beneficial bacterium Pseudomonas protegens CHA0 is the receptor of its natural predator, the phage ΦGP100. We examined the distribution of the gene cluster directing the synthesis of this O-PS and identified signatures of horizontal gene acquisitions. Altogether, our study highlights the importance of bacterial cell surface structure variation in the complex interplay between phages and their Pseudomonas hosts.
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Affiliation(s)
- Jordan Vacheron
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Clara M. Heiman
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Julian R. Garneau
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Peter Kupferschmied
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Ronnie de Jonge
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht, the Netherlands
| | - Daniel Garrido-Sanz
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Christoph Keel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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Lurthy T, Perot S, Gerin‐Eveillard F, Rey M, Wisniewski‐Dyé F, Vacheron J, Prigent‐Combaret C. Inhibition of broomrape germination by 2,4-diacetylphloroglucinol produced by environmental Pseudomonas. Microb Biotechnol 2023; 16:2313-2325. [PMID: 37897154 PMCID: PMC10686154 DOI: 10.1111/1751-7915.14336] [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: 05/04/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 10/29/2023] Open
Abstract
Parasitic weeds such as broomrapes (Phelipanche ramosa and Orobanche cumana) cause severe damage to crops and their development must be controlled. Given that phloroglucinol compounds (PGCs) produced by environmental Pseudomonas could be toxic towards certain plants, we assessed the potential herbicidal effect of the bacterial model Pseudomonas ogarae F113, a PGCs-producing bacterium, on parasitic weed. By combining the use of a mutagenesis approach and of pure PGCs, we evaluated the in vitro effect of PGC-produced by P. ogarae F113 on broomrape germination and assessed the protective activity of a PGC-producing bacteria on oilseed rape (Brassica napus) against P. ramosa in non-sterile soils. We showed that the inhibition of the germination depends on the PGCs molecular structure and their concentrations as well as the broomrape species and pathovars. This inhibition caused by the PGCs is irreversible, causing a brown coloration of the broomrape seeds. The inoculation of PGCs-producing bacteria limited the broomrape infection of P. ramosa, without affecting the host growth. Moreover, elemental profiling analysis of oilseed rape revealed that neither F113 nor applied PGCs affected the nutrition capacity of the oilseed rape host. Our study expands the knowledge on plant-beneficial Pseudomonas as weed biocontrol agents and opens new avenues for the development of natural bioherbicides to enhance crop yield.
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Affiliation(s)
- Tristan Lurthy
- Ecologie MicrobienneUniversité Claude Bernard Lyon1, Université de Lyon, CNRS UMR‐5557, INRAe UMR‐1418, VetAgro SupVilleurbanneFrance
| | - Ségolène Perot
- Ecologie MicrobienneUniversité Claude Bernard Lyon1, Université de Lyon, CNRS UMR‐5557, INRAe UMR‐1418, VetAgro SupVilleurbanneFrance
| | - Florence Gerin‐Eveillard
- Ecologie MicrobienneUniversité Claude Bernard Lyon1, Université de Lyon, CNRS UMR‐5557, INRAe UMR‐1418, VetAgro SupVilleurbanneFrance
| | - Marjolaine Rey
- Ecologie MicrobienneUniversité Claude Bernard Lyon1, Université de Lyon, CNRS UMR‐5557, INRAe UMR‐1418, VetAgro SupVilleurbanneFrance
| | - Florence Wisniewski‐Dyé
- Ecologie MicrobienneUniversité Claude Bernard Lyon1, Université de Lyon, CNRS UMR‐5557, INRAe UMR‐1418, VetAgro SupVilleurbanneFrance
| | - Jordan Vacheron
- Department of Fundamental MicrobiologyUniversity of LausanneLausanneSwitzerland
| | - Claire Prigent‐Combaret
- Ecologie MicrobienneUniversité Claude Bernard Lyon1, Université de Lyon, CNRS UMR‐5557, INRAe UMR‐1418, VetAgro SupVilleurbanneFrance
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Zamanzadeh-Nasrabadi SM, Mohammadiapanah F, Sarikhan S, Shariati V, Saghafi K, Hosseini-Mazinani M. Comprehensive genome analysis of Pseudomonas sp. SWRIQ11, a new plant growth-promoting bacterium that alleviates salinity stress in olive. 3 Biotech 2023; 13:347. [PMID: 37750167 PMCID: PMC10517913 DOI: 10.1007/s13205-023-03755-0] [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: 12/20/2022] [Accepted: 08/20/2023] [Indexed: 09/27/2023] Open
Abstract
The study presents the genome analysis of a new Pseudomonas sp. (SWRIQ11), which can alleviate salinity stress effects on growth of olive seedlings in greenhouse study. The strain SWRIQ11 can tolerate salinity up to 6%, produce siderophores, indole acetic acid (IAA), aminocyclopropane-1-carboxylate (ACC) deaminase, and has the phosphate-solubilizing capability. The SWRIQ11 genome contained an assembly size of 6,196,390 bp with a GC content of 60.1%. According to derived indices based on whole-genome sequences for species delineation, including tetra nucleotide usage patterns (TETRA), genome-to-genome distance (GGDC), and average nucleotide identity (ANI), Pseudomonas sp. SWRIQ11 can be considered a novel species candidate. The phylogenetic analysis revealed SWRIQ11 clusters with Pseudomonas tehranensis SWRI196 in the same clade. The SWRIQ11 genome was rich in genes related to stress sensing, signaling, and response, chaperones, motility, attachments, colonization, and enzymes for degrading plant-derived carbohydrates. Furthermore, the genes for production of exopolysaccharides, osmoprotectants, phytohormones, and ACC deaminase, ion homeostasis, nutrient acquisition, and antioxidant defenses were identified in the SWRIQ11 genome. The results of genome analysis (identification of more than 825 CDSs related to plant growth-promoting and stress-alleviating traits in the SWRIQ11 genome which is more than 15% of its total CDSs) are in accordance with laboratory and greenhouse experiments assigning the Pseudomonas sp. SWRIQ11 as a halotolerant plant growth-promoting bacterium (PGPB). This research highlights the potential safe application of this new PGPB species in agriculture as a potent biofertilizer.
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Affiliation(s)
- Seyyedeh Maryam Zamanzadeh-Nasrabadi
- Pharmaceutial Biotechnology Lab, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, 14155-6455 Iran
| | - Fatemeh Mohammadiapanah
- Pharmaceutial Biotechnology Lab, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, 14155-6455 Iran
| | - Sajjad Sarikhan
- Molecular Bank, Iranian Biological Resource Center (IBRC), ACECR, Tehran, Iran
| | - Vahid Shariati
- Agricultural Biotechnology Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Kobra Saghafi
- Soil and Water Research Institute (SWRI), Karaj, Iran
| | - Mehdi Hosseini-Mazinani
- Agricultural Biotechnology Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
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Garrido-Sanz D, Čaušević S, Vacheron J, Heiman CM, Sentchilo V, van der Meer JR, Keel C. Changes in structure and assembly of a species-rich soil natural community with contrasting nutrient availability upon establishment of a plant-beneficial Pseudomonas in the wheat rhizosphere. MICROBIOME 2023; 11:214. [PMID: 37770950 PMCID: PMC10540321 DOI: 10.1186/s40168-023-01660-5] [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: 03/28/2023] [Accepted: 08/31/2023] [Indexed: 09/30/2023]
Abstract
BACKGROUND Plant-beneficial bacterial inoculants are of great interest in agriculture as they have the potential to promote plant growth and health. However, the inoculation of the rhizosphere microbiome often results in a suboptimal or transient colonization, which is due to a variety of factors that influence the fate of the inoculant. To better understand the fate of plant-beneficial inoculants in complex rhizosphere microbiomes, composed by hundreds of genotypes and multifactorial selection mechanisms, controlled studies with high-complexity soil microbiomes are needed. RESULTS We analysed early compositional changes in a taxa-rich natural soil bacterial community under both exponential nutrient-rich and stationary nutrient-limited growth conditions (i.e. growing and stable communities, respectively) following inoculation with the plant-beneficial bacterium Pseudomonas protegens in a bulk soil or a wheat rhizosphere environment. P. protegens successfully established under all conditions tested and was more abundant in the rhizosphere of the stable community. Nutrient availability was a major factor driving microbiome composition and structure as well as the underlying assembly processes. While access to nutrients resulted in communities assembled mainly by homogeneous selection, stochastic processes dominated under the nutrient-deprived conditions. We also observed an increased rhizosphere selection effect under nutrient-limited conditions, resulting in a higher number of amplicon sequence variants (ASVs) whose relative abundance was enriched. The inoculation with P. protegens produced discrete changes, some of which involved other Pseudomonas. Direct competition between Pseudomonas strains partially failed to replicate the observed differences in the microbiome and pointed to a more complex interaction network. CONCLUSIONS The results of this study show that nutrient availability is a major driving force of microbiome composition, structure and diversity in both the bulk soil and the wheat rhizosphere and determines the assembly processes that govern early microbiome development. The successful establishment of the inoculant was facilitated by the wheat rhizosphere and produced discrete changes among other members of the microbiome. Direct competition between Pseudomonas strains only partially explained the microbiome changes, indicating that indirect interactions or spatial distribution in the rhizosphere or soil interface may be crucial for the survival of certain bacteria. Video Abstract.
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Affiliation(s)
- Daniel Garrido-Sanz
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland.
| | - Senka Čaušević
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Jordan Vacheron
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Clara M Heiman
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Vladimir Sentchilo
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Jan Roelof van der Meer
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Christoph Keel
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland.
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Pastora AB, O’Toole GA. The regulator FleQ both transcriptionally and post-transcriptionally regulates the level of RTX adhesins of Pseudomonas fluorescens. J Bacteriol 2023; 205:e0015223. [PMID: 37655913 PMCID: PMC10521353 DOI: 10.1128/jb.00152-23] [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: 05/08/2023] [Accepted: 07/07/2023] [Indexed: 09/02/2023] Open
Abstract
Biofilm formation by the Gram-negative, Gammaproteobacteria Pseudomonas fluorescens relies on the repeats-in-toxin adhesins LapA and MapA in the cytoplasm, secretion of these adhesins through their respective type 1 secretion systems, and retention at the cell surface. Published work has shown that retention of the adhesins occurs via a post-translational mechanism involving the cyclic-di-GMP receptor LapD and the protease LapG. However, little is known about the underlying mechanisms that regulate the level of these adhesins. Here, we demonstrate that the master regulator FleQ modulates biofilm formation by both transcriptionally and post-transcriptionally regulating LapA and MapA. We find that a ΔfleQ mutant has a biofilm formation defect compared to the wild-type (WT) strain, which is attributed in part to a decrease in LapA and MapA abundance in the cell, despite the ΔfleQ mutant having increased levels of lapA and mapA transcripts compared to the WT strain. Through transposon mutagenesis and subsequent genetic analysis, we found that overstimulation of the Gac/Rsm pathway partially rescues biofilm formation in the ΔfleQ mutant background. Collectively, these findings provide evidence that FleQ regulates biofilm formation by both transcriptionally regulating the expression of the lapA and mapA genes and post-transcriptionally regulating the abundance of LapA and MapA, and that activation of the Gac/Rsm pathway can post-transcriptionally enhance biofilm formation by P. fluorescens. IMPORTANCE Biofilm formation is a highly coordinated process that bacteria undergo to colonize a variety of surfaces. For Pseudomonas fluorescens, biofilm formation requires the production and localization of repeats-in-toxin adhesins to the cell surface. To date, little is known about the underlying mechanisms that regulate biofilm formation by P. fluorescens. Here, we identify FleQ as a key regulator of biofilm formation that modulates both gene expression and abundance of LapA and MapA through both a transcriptional and post-transcriptional mechanism. We provide further evidence implicating activation of the Gac/Rsm system in FleQ-dependent regulation of biofilm formation. Together, our findings uncover evidence for a dual mechanism of transcriptional and post-transcriptional regulation of the LapA and MapA adhesins.
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Affiliation(s)
- Alexander B. Pastora
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - George A. O’Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Sarkar S, Kamke A, Ward K, Hartung E, Ran Q, Feehan B, Galliart M, Jumpponen A, Johnson L, Lee ST. Pseudomonas cultivated from Andropogon gerardii rhizosphere show functional potential for promoting plant host growth and drought resilience. BMC Genomics 2022; 23:784. [PMID: 36451103 PMCID: PMC9710129 DOI: 10.1186/s12864-022-09019-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 11/16/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Climate change will result in more frequent droughts that can impact soil-inhabiting microbiomes (rhizobiomes) in the agriculturally vital North American perennial grasslands. Rhizobiomes have contributed to enhancing drought resilience and stress resistance properties in plant hosts. In the predicted events of more future droughts, how the changing rhizobiome under environmental stress can impact the plant host resilience needs to be deciphered. There is also an urgent need to identify and recover candidate microorganisms along with their functions, involved in enhancing plant resilience, enabling the successful development of synthetic communities. RESULTS In this study, we used the combination of cultivation and high-resolution genomic sequencing of bacterial communities recovered from the rhizosphere of a tallgrass prairie foundation grass, Andropogon gerardii. We cultivated the plant host-associated microbes under artificial drought-induced conditions and identified the microbe(s) that might play a significant role in the rhizobiome of Andropogon gerardii under drought conditions. Phylogenetic analysis of the non-redundant metagenome-assembled genomes (MAGs) identified a bacterial genome of interest - MAG-Pseudomonas. Further metabolic pathway and pangenome analyses recovered genes and pathways related to stress responses including ACC deaminase; nitrogen transformation including assimilatory nitrate reductase in MAG-Pseudomonas, which might be associated with enhanced drought tolerance and growth for Andropogon gerardii. CONCLUSIONS Our data indicated that the metagenome-assembled MAG-Pseudomonas has the functional potential to contribute to the plant host's growth during stressful conditions. Our study also suggested the nitrogen transformation potential of MAG-Pseudomonas that could impact Andropogon gerardii growth in a positive way. The cultivation of MAG-Pseudomonas sets the foundation to construct a successful synthetic community for Andropogon gerardii. To conclude, stress resilience mediated through genes ACC deaminase, nitrogen transformation potential through assimilatory nitrate reductase in MAG-Pseudomonas could place this microorganism as an important candidate of the rhizobiome aiding the plant host resilience under environmental stress. This study, therefore, provided insights into the MAG-Pseudomonas and its potential to optimize plant productivity under ever-changing climatic patterns, especially in frequent drought conditions.
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Affiliation(s)
- Soumyadev Sarkar
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
| | - Abigail Kamke
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
| | - Kaitlyn Ward
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
| | - Eli Hartung
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
| | - Qinghong Ran
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
| | - Brandi Feehan
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
| | - Matthew Galliart
- grid.256032.00000 0001 2285 6924Department of Biological Sciences, Fort Hays State University, Hays, KS USA
| | - Ari Jumpponen
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
| | - Loretta Johnson
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
| | - Sonny T.M. Lee
- grid.36567.310000 0001 0737 1259Division of Biology, Kansas State University, Manhattan, KS USA
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Overgaard CK, Tao K, Zhang S, Christensen BT, Blahovska Z, Radutoiu S, Kelly S, Dueholm MKD. Application of ecosystem-specific reference databases for increased taxonomic resolution in soil microbial profiling. Front Microbiol 2022; 13:942396. [DOI: 10.3389/fmicb.2022.942396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022] Open
Abstract
Intensive agriculture systems have paved the way for a growing human population. However, the abundant use of mineral fertilizers and pesticides may negatively impact nutrient cycles and biodiversity. One potential alternative is to harness beneficial relationships between plants and plant-associated rhizobacteria to increase nutrient-use efficiency and provide pathogen resistance. Plant-associated microbiota profiling can be achieved using high-throughput 16S rRNA gene amplicon sequencing. However, interrogation of these data is limited by confident taxonomic classifications at high taxonomic resolution (genus- or species level) with the commonly applied universal reference databases. High-throughput full-length 16S rRNA gene sequencing combined with automated taxonomy assignment (AutoTax) can be used to create amplicon sequence variant resolved ecosystems-specific reference databases that are superior to the traditional universal reference databases. This approach was used here to create a custom reference database for bacteria and archaea based on 987,353 full-length 16S rRNA genes from Askov and Cologne soils. We evaluated the performance of the database using short-read amplicon data and found that it resulted in the increased genus- and species-level classification compared to commonly use universal reference databases. The custom database was utilized to evaluate the ecosystem-specific primer bias and taxonomic resolution of amplicon primers targeting the V5–V7 region of the 16S rRNA gene commonly used within the plant microbiome field. Finally, we demonstrate the benefits of custom ecosystem-specific databases through the analysis of V5–V7 amplicon data to identify new plant-associated microbes for two legumes and two cereal species.
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Regulation of extracellular matrix components by AmrZ is mediated by c-di-GMP in Pseudomonas ogarae F113. Sci Rep 2022; 12:11914. [PMID: 35831472 PMCID: PMC9279365 DOI: 10.1038/s41598-022-16162-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 07/05/2022] [Indexed: 12/04/2022] Open
Abstract
The AmrZ/FleQ hub has been identified as a central node in the regulation of environmental adaption in the plant growth-promoting rhizobacterium and model for rhizosphere colonization Pseudomonas ogarae F113. AmrZ is involved in the regulation of motility, biofilm formation, and bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) turnover, among others, in this bacterium. The mutants in amrZ have a pleiotropic phenotype with distinguishable colony morphology, reduced biofilm formation, increased motility, and are severely impaired in competitive rhizosphere colonization. Here, RNA-Seq and qRT-PCR gene expression analyses revealed that AmrZ regulates many genes related to the production of extracellular matrix (ECM) components at the transcriptional level. Furthermore, overproduction of c-di-GMP in an amrZ mutant, by ectopic production of the Caulobacter crescentus constitutive diguanylate cyclase PleD*, resulted in increased expression of many genes implicated in the synthesis of ECM components. The overproduction of c-di-GMP in the amrZ mutant also suppressed the biofilm formation and motility phenotypes, but not the defect in competitive rhizosphere colonization. These results indicate that although biofilm formation and motility are mainly regulated indirectly by AmrZ, through the modulation of c-di-GMP levels, the implication of AmrZ in rhizosphere competitive colonization occurs in a c-di-GMP-independent manner.
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12
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Ali MA, Luo J, Ahmed T, Zhang J, Xie T, Dai D, Jiang J, Zhu J, Hassan S, Alorabi JA, Li B, An Q. Pseudomonas bijieensis Strain XL17 within the P. corrugata Subgroup Producing 2,4-Diacetylphloroglucinol and Lipopeptides Controls Bacterial Canker and Gray Mold Pathogens of Kiwifruit. Microorganisms 2022; 10:425. [PMID: 35208879 PMCID: PMC8878242 DOI: 10.3390/microorganisms10020425] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/09/2022] [Accepted: 02/10/2022] [Indexed: 11/21/2022] Open
Abstract
Kiwifruit worldwide suffers from the devastating diseases of bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa) and gray mold caused by Botrytis cinerea. Here, an endophytic bacterium XL17 isolated from a rape crown gall was screened out for its potent antagonistic activities against Psa and B. cinerea. Strain XL17 and its cell-free culture filtrate (CF) inhibited the growth of Psa and B. cinerea, Psa-associated leaf necrosis, and B. cinerea-associated kiwifruit necrosis. Electron microscopy showed that XL17 CF could damage the cell structures of Psa and B. cinerea. Genome-based taxonomy revealed that strain XL17 belongs to Pseudomonas bijieensis within the P. corrugata subgroup of the P. fluorescens species complex. Among the P. corrugata subgroup containing 31 genomospecies, the presence of the phl operon responsible for the biosynthesis of the phenolic polyketide 2,4-diacetylphloroglucinol (DAPG) and the absence of the lipopeptide/quorum sensing island can serve as the genetic marker for the determination of a plant-protection life style. HPLC detected DAPG in extracts from XL17 CF. MALDI-TOF-MS analysis revealed that strain XL17 produced cyclic lipopeptides of the viscosin family and orfamide family. Together, phenotypic, genomic, and metabolic analyses identified that P. bijieensis XL17 producing DAPG and cyclic lipopeptides can be used to control bacterial canker and gray mold pathogens of kiwifruit.
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Affiliation(s)
- Md. Arshad Ali
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, College of Agricultural and Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.A.A.); (T.A.); (J.Z.); (T.X.); (B.L.)
| | - Jinyan Luo
- Department of Plant Quarantine, Shanghai Extension and Service Center of Agriculture Technology, Shanghai 201103, China;
| | - Temoor Ahmed
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, College of Agricultural and Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.A.A.); (T.A.); (J.Z.); (T.X.); (B.L.)
| | - Jiannan Zhang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, College of Agricultural and Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.A.A.); (T.A.); (J.Z.); (T.X.); (B.L.)
| | - Ting Xie
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, College of Agricultural and Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.A.A.); (T.A.); (J.Z.); (T.X.); (B.L.)
| | - Dejiang Dai
- Station for the Plant Protection & Quarantine and Control of Agrochemicals Zhejiang Province, Hangzhou 310004, China
| | - Jingyong Jiang
- Taizhou Academy of Agricultural Sciences, Linhai 317000, China;
| | - Jie Zhu
- Wenzhou Station of Plant Protection, Soils and Fertilizers, Wenzhou 325000, China;
| | - Sabry Hassan
- Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; (S.H.); (J.A.A.)
| | - Jamal A. Alorabi
- Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; (S.H.); (J.A.A.)
| | - Bin Li
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, College of Agricultural and Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.A.A.); (T.A.); (J.Z.); (T.X.); (B.L.)
| | - Qianli An
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, College of Agricultural and Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.A.A.); (T.A.); (J.Z.); (T.X.); (B.L.)
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13
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Oren A, Garrity GM. Valid publication of new names and new combinations effectively published outside the IJSEM. Validation List no. 203. Int J Syst Evol Microbiol 2022; 72. [PMID: 35108178 DOI: 10.1099/ijsem.0.005167] [Citation(s) in RCA: 275] [Impact Index Per Article: 137.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Aharon Oren
- The Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus, 9190401 Jerusalem, Israel
| | - George M Garrity
- Department of Microbiology & Molecular Genetics, Biomedical Physical Sciences, Michigan State University, East Lansing, MI 48824-4320, USA
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14
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Zboralski A, Biessy A, Filion M. Bridging the Gap: Type III Secretion Systems in Plant-Beneficial Bacteria. Microorganisms 2022; 10:187. [PMID: 35056636 PMCID: PMC8780523 DOI: 10.3390/microorganisms10010187] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 12/30/2022] Open
Abstract
Type III secretion systems (T3SSs) are bacterial membrane-embedded nanomachines translocating effector proteins into the cytoplasm of eukaryotic cells. They have been intensively studied for their important roles in animal and plant bacterial diseases. Over the past two decades, genome sequencing has unveiled their ubiquitous distribution in many taxa of Gram-negative bacteria, including plant-beneficial ones. Here, we discuss the distribution and functions of the T3SS in two agronomically important bacterial groups: the symbiotic nodule-forming nitrogen-fixing rhizobia and the free-living plant-beneficial Pseudomonas spp. In legume-rhizobia symbiosis, T3SSs and their cognate effectors play important roles, including the modulation of the plant immune response and the initiation of the nodulation process in some cases. In plant-beneficial Pseudomonas spp., the roles of T3SSs are not fully understood, but pertain to plant immunity suppression, biocontrol against eukaryotic plant pathogens, mycorrhization facilitation, and possibly resistance against protist predation. The diversity of T3SSs in plant-beneficial bacteria points to their important roles in multifarious interkingdom interactions in the rhizosphere. We argue that the gap in research on T3SSs in plant-beneficial bacteria must be bridged to better understand bacteria/eukaryotes rhizosphere interactions and to support the development of efficient plant-growth promoting microbial inoculants.
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Affiliation(s)
| | | | - Martin Filion
- Research and Development Centre, Agriculture and Agri-Food Canada, 430 Gouin Boulevard, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada; (A.Z.); (A.B.)
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15
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Blanco-Romero E, Durán D, Garrido-Sanz D, Rivilla R, Martín M, Redondo-Nieto M. Transcriptomic analysis of Pseudomonas ogarae F113 reveals the antagonistic roles of AmrZ and FleQ during rhizosphere adaption. Microb Genom 2022; 8. [PMID: 35012704 PMCID: PMC8914362 DOI: 10.1099/mgen.0.000750] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Rhizosphere colonization by bacteria involves molecular and cellular mechanisms, such as motility and chemotaxis, biofilm formation, metabolic versatility, or biosynthesis of secondary metabolites, among others. Nonetheless, there is limited knowledge concerning the main regulatory factors that drive the rhizosphere colonization process. Here we show the importance of the AmrZ and FleQ transcription factors for adaption in the plant growth-promoting rhizobacterium (PGPR) and rhizosphere colonization model Pseudomonas ogarae F113. RNA-Seq analyses of P. ogarae F113 grown in liquid cultures either in exponential and stationary growth phase, and rhizosphere conditions, revealed that rhizosphere is a key driver of global changes in gene expression in this bacterium. Regarding the genetic background, this work has revealed that a mutation in fleQ causes considerably more alterations in the gene expression profile of this bacterium than a mutation in amrZ under rhizosphere conditions. The functional analysis has revealed that in P. ogarae F113, the transcription factors AmrZ and FleQ regulate genes involved in diverse bacterial functions. Notably, in the rhizosphere, these transcription factors antagonistically regulate genes related to motility, biofilm formation, nitrogen, sulfur, and amino acid metabolism, transport, signalling, and secretion, especially the type VI secretion systems. These results define the regulon of two important bifunctional transcriptional regulators in pseudomonads during the process of rhizosphere colonization.
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Affiliation(s)
- Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain.,Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
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