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Huang W, Wang D, Zhang XX, Zhao M, Sun L, Zhou Y, Guan X, Xie Z. Regulatory roles of the second messenger c-di-GMP in beneficial plant-bacteria interactions. Microbiol Res 2024; 285:127748. [PMID: 38735241 DOI: 10.1016/j.micres.2024.127748] [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: 10/11/2023] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/14/2024]
Abstract
The rhizosphere system of plants hosts a diverse consortium of bacteria that confer beneficial effects on plant, such as plant growth-promoting rhizobacteria (PGPR), biocontrol agents with disease-suppression activities, and symbiotic nitrogen fixing bacteria with the formation of root nodule. Efficient colonization in planta is of fundamental importance for promoting of these beneficial activities. However, the process of root colonization is complex, consisting of multiple stages, including chemotaxis, adhesion, aggregation, and biofilm formation. The secondary messenger, c-di-GMP (cyclic bis-(3'-5') dimeric guanosine monophosphate), plays a key regulatory role in a variety of physiological processes. This paper reviews recent progress on the actions of c-di-GMP in plant beneficial bacteria, with a specific focus on its role in chemotaxis, biofilm formation, and nodulation.
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Affiliation(s)
- Weiwei Huang
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Dandan Wang
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Xue-Xian Zhang
- School of Natural Sciences, Massey University at Albany, Auckland 0745, New Zealand
| | - Mengguang Zhao
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Li Sun
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Yanan Zhou
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Xin Guan
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Zhihong Xie
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China.
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2
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Pacheco-Moreno A, Bollmann-Giolai A, Chandra G, Brett P, Davies J, Thornton O, Poole P, Ramachandran V, Brown JKM, Nicholson P, Ridout C, DeVos S, Malone JG. The genotype of barley cultivars influences multiple aspects of their associated microbiota via differential root exudate secretion. PLoS Biol 2024; 22:e3002232. [PMID: 38662644 PMCID: PMC11045101 DOI: 10.1371/journal.pbio.3002232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 03/19/2024] [Indexed: 04/28/2024] Open
Abstract
Plant-associated microbes play vital roles in promoting plant growth and health, with plants secreting root exudates into the rhizosphere to attract beneficial microbes. Exudate composition defines the nature of microbial recruitment, with different plant species attracting distinct microbiota to enable optimal adaptation to the soil environment. To more closely examine the relationship between plant genotype and microbial recruitment, we analysed the rhizosphere microbiomes of landrace (Chevallier) and modern (NFC Tipple) barley (Hordeum vulgare) cultivars. Distinct differences were observed between the plant-associated microbiomes of the 2 cultivars, with the plant-growth promoting rhizobacterial genus Pseudomonas substantially more abundant in the Tipple rhizosphere. Striking differences were also observed between the phenotypes of recruited Pseudomonas populations, alongside distinct genotypic clustering by cultivar. Cultivar-driven Pseudomonas selection was driven by root exudate composition, with the greater abundance of hexose sugars secreted from Tipple roots attracting microbes better adapted to growth on these metabolites and vice versa. Cultivar-driven selection also operates at the molecular level, with both gene expression and the abundance of ecologically relevant loci differing between Tipple and Chevallier Pseudomonas isolates. Finally, cultivar-driven selection is important for plant health, with both cultivars showing a distinct preference for microbes selected by their genetic siblings in rhizosphere transplantation assays.
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Affiliation(s)
- Alba Pacheco-Moreno
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | | | - Govind Chandra
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Paul Brett
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Jack Davies
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Owen Thornton
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Philip Poole
- Department of Biology, University of Oxford, South Parks Road, Oxford, United Kingdom
| | - Vinoy Ramachandran
- Department of Biology, University of Oxford, South Parks Road, Oxford, United Kingdom
| | - James K. M. Brown
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Paul Nicholson
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Chris Ridout
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
- New Heritage Barley, Norwich Research Park, Norwich, United Kingdom
| | - Sarah DeVos
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
- New Heritage Barley, Norwich Research Park, Norwich, United Kingdom
| | - Jacob G. Malone
- John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
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3
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Villalobos-Escobedo JM, Mercado-Esquivias MB, Adams C, Kauffman WB, Malmstrom RR, Deutschbauer AM, Glass NL. Genome-wide fitness profiling reveals molecular mechanisms that bacteria use to interact with Trichoderma atroviride exometabolites. PLoS Genet 2023; 19:e1010909. [PMID: 37651474 PMCID: PMC10516422 DOI: 10.1371/journal.pgen.1010909] [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: 04/23/2023] [Revised: 09/22/2023] [Accepted: 08/07/2023] [Indexed: 09/02/2023] Open
Abstract
Trichoderma spp. are ubiquitous rhizosphere fungi capable of producing several classes of secondary metabolites that can modify the dynamics of the plant-associated microbiome. However, the bacterial-fungal mechanisms that mediate these interactions have not been fully characterized. Here, a random barcode transposon-site sequencing (RB-TnSeq) approach was employed to identify bacterial genes important for fitness in the presence of Trichoderma atroviride exudates. We selected three rhizosphere bacteria with RB-TnSeq mutant libraries that can promote plant growth: the nitrogen fixers Klebsiella michiganensis M5aI and Herbaspirillum seropedicae SmR1, and Pseudomonas simiae WCS417. As a non-rhizosphere species, Pseudomonas putida KT2440 was also included. From the RB-TnSeq data, nitrogen-fixing bacteria competed mainly for iron and required the siderophore transport system TonB/ExbB for optimal fitness in the presence of T. atroviride exudates. In contrast, P. simiae and P. putida were highly dependent on mechanisms associated with membrane lipid modification that are required for resistance to cationic antimicrobial peptides (CAMPs). A mutant in the Hog1-MAP kinase (Δtmk3) gene of T. atroviride showed altered expression patterns of many nonribosomal peptide synthetase (NRPS) biosynthetic gene clusters with potential antibiotic activity. In contrast to exudates from wild-type T. atroviride, bacterial mutants containing lesions in genes associated with resistance to antibiotics did not show fitness defects when RB-TnSeq libraries were exposed to exudates from the Δtmk3 mutant. Unexpectedly, exudates from wild-type T. atroviride and the Δtmk3 mutant rescued purine auxotrophic mutants of H. seropedicae, K. michiganensis and P. simiae. Metabolomic analysis on exudates from wild-type T. atroviride and the Δtmk3 mutant showed that both strains excrete purines and complex metabolites; functional Tmk3 is required to produce some of these metabolites. This study highlights the complex interplay between Trichoderma-metabolites and soil bacteria, revealing both beneficial and antagonistic effects, and underscoring the intricate and multifaceted nature of this relationship.
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Affiliation(s)
- José Manuel Villalobos-Escobedo
- Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Maria Belen Mercado-Esquivias
- Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Catharine Adams
- Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - W. Berkeley Kauffman
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Rex R. Malmstrom
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Adam M. Deutschbauer
- Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - N. Louise Glass
- Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
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4
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Thompson CMA, Hall JPJ, Chandra G, Martins C, Saalbach G, Panturat S, Bird SM, Ford S, Little RH, Piazza A, Harrison E, Jackson RW, Brockhurst MA, Malone JG. Plasmids manipulate bacterial behaviour through translational regulatory crosstalk. PLoS Biol 2023; 21:e3001988. [PMID: 36787297 PMCID: PMC9928087 DOI: 10.1371/journal.pbio.3001988] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 01/04/2023] [Indexed: 02/15/2023] Open
Abstract
Beyond their role in horizontal gene transfer, conjugative plasmids commonly encode homologues of bacterial regulators. Known plasmid regulator homologues have highly targeted effects upon the transcription of specific bacterial traits. Here, we characterise a plasmid translational regulator, RsmQ, capable of taking global regulatory control in Pseudomonas fluorescens and causing a behavioural switch from motile to sessile lifestyle. RsmQ acts as a global regulator, controlling the host proteome through direct interaction with host mRNAs and interference with the host's translational regulatory network. This mRNA interference leads to large-scale proteomic changes in metabolic genes, key regulators, and genes involved in chemotaxis, thus controlling bacterial metabolism and motility. Moreover, comparative analyses found RsmQ to be encoded on a large number of divergent plasmids isolated from multiple bacterial host taxa, suggesting the widespread importance of RsmQ for manipulating bacterial behaviour across clinical, environmental, and agricultural niches. RsmQ is a widespread plasmid global translational regulator primarily evolved for host chromosomal control to manipulate bacterial behaviour and lifestyle.
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Affiliation(s)
- Catriona M. A. Thompson
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, United Kingdom
| | - James P. J. Hall
- Department of Evolution, Ecology and Behaviour Institute of Infection, Veterinary and Ecological Sciences University of Liverpool, Crown Street, Liverpool, United Kingdom
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, United Kingdom
| | - Carlo Martins
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, United Kingdom
| | - Gerhard Saalbach
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, United Kingdom
| | - Supakan Panturat
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, United Kingdom
| | - Susannah M. Bird
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Samuel Ford
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Richard H. Little
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, United Kingdom
| | - Ainelen Piazza
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, United Kingdom
| | - Ellie Harrison
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Robert W. Jackson
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Michael A. Brockhurst
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Jacob G. Malone
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, United Kingdom
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5
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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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6
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Pacheco-Moreno A, Stefanato FL, Ford JJ, Trippel C, Uszkoreit S, Ferrafiat L, Grenga L, Dickens R, Kelly N, Kingdon AD, Ambrosetti L, Nepogodiev SA, Findlay KC, Cheema J, Trick M, Chandra G, Tomalin G, Malone JG, Truman AW. Pan-genome analysis identifies intersecting roles for Pseudomonas specialized metabolites in potato pathogen inhibition. eLife 2021; 10:71900. [PMID: 34792466 PMCID: PMC8719888 DOI: 10.7554/elife.71900] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/16/2021] [Indexed: 11/29/2022] Open
Abstract
Agricultural soil harbors a diverse microbiome that can form beneficial relationships with plants, including the inhibition of plant pathogens. Pseudomonas spp. are one of the most abundant bacterial genera in the soil and rhizosphere and play important roles in promoting plant health. However, the genetic determinants of this beneficial activity are only partially understood. Here, we genetically and phenotypically characterize the Pseudomonas fluorescens population in a commercial potato field, where we identify strong correlations between specialized metabolite biosynthesis and antagonism of the potato pathogens Streptomyces scabies and Phytophthora infestans. Genetic and chemical analyses identified hydrogen cyanide and cyclic lipopeptides as key specialized metabolites associated with S. scabies inhibition, which was supported by in planta biocontrol experiments. We show that a single potato field contains a hugely diverse and dynamic population of Pseudomonas bacteria, whose capacity to produce specialized metabolites is shaped both by plant colonization and defined environmental inputs. Potato scab and blight are two major diseases which can cause heavy crop losses. They are caused, respectively, by the bacterium Streptomyces scabies and an oomycete (a fungus-like organism) known as Phytophthora infestans. Fighting these disease-causing microorganisms can involve crop management techniques – for example, ensuring that a field is well irrigated helps to keep S. scabies at bay. Harnessing biological control agents can also offer ways to control disease while respecting the environment. Biocontrol bacteria, such as Pseudomonas, can produce compounds that keep S. scabies and P. infestans in check. However, the identity of these molecules and how irrigation can influence Pseudomonas population remains unknown. To examine these questions, Pacheco-Moreno et al. sampled and isolated hundreds of Pseudomonas strains from a commercial potato field, closely examining the genomes of 69 of these. Comparing the genetic information of strains based on whether they could control the growth of S. scabies revealed that compounds known as cyclic lipopeptides are key to controlling the growth of S. scabies and P. infestans. Whether the field was irrigated also had a large impact on the strains forming the Pseudomonas population. Working out how Pseudomonas bacteria block disease could speed up the search for biological control agents. The approach developed by Pacheco-Moreno et al. could help to predict which strains might be most effective based on their genetic features. Similar experiments could also work for other combinations of plants and diseases.
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Affiliation(s)
- Alba Pacheco-Moreno
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jonathan J Ford
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Christine Trippel
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Simon Uszkoreit
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Laura Ferrafiat
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Lucia Grenga
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Ruth Dickens
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Nathan Kelly
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Alexander Dh Kingdon
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Liana Ambrosetti
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Sergey A Nepogodiev
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich, United Kingdom
| | - Kim C Findlay
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Jitender Cheema
- Department of Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Martin Trick
- Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Andrew W Truman
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
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7
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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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8
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Wu P, Wang Z, Zhu Q, Xie Z, Mei Y, Liang Y, Chen Z. Stress preadaptation and overexpression of rpoS and hfq genes increase stress resistance of Pseudomonas fluorescens ATCC13525. Microbiol Res 2021; 250:126804. [PMID: 34144508 DOI: 10.1016/j.micres.2021.126804] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/17/2021] [Accepted: 06/02/2021] [Indexed: 01/06/2023]
Abstract
Pseudomonas fluorescens ATCC13525 is an important growth-promoting rhizobacteria (PGPR) and plant disease biocontrol bacterium. However, due to poor stress resistance, it is prone to be inactivated by preparation, drying and storage. In this study, we investigated the effects of different stress preadaptation methods (2.0∼3.0 wt% NaCl, 0.01∼0.20 wt% H2O2, and 35∼44 °C) and two stress adaptation genes (rpoS, and hfq) on the stress resistance of P. fluorescens ATCC13525 (PF-WT). After stress preadaptation with low stress of 3.0 wt% NaCl, 0.05 wt% H2O2, and 41 °C for 30 min, the tolerance of PF-WT toward high lethal stress environments (20.0 wt% NaCl, 1.00 wt% H2O2, and 47 °C) were significantly improved. Moreover, knockout of rpoS and hfq genes resulted in slower culture growth than PF-WT under the sublethal stress culture conditions (5.0 wt% NaCl, 0.08 wt% H2O2, and 35 °C), whereas rpoS and hfq overexpressed strains (PF-pBBR2-rpoS and PF-pBBR2-hfq) obviously grew better than the control strain PF-pBBR2. Further, we prepared biocontrol agents (BACs) of different strains after different stress preadaptation treatments. Compared to PF-WT without stress preadaptation, preadaptation by 0.05 wt% H2O2 for 30 min resulted in 5.65 times higher survival rate, while treatment with 3.0 wt% NaCl for 30 min of PF-pBBR2-rpoS led to 5.60 times higher survival rate. This finding provides the simple and effective protection methods for P. fluorescens ATCC13525 BACs preparation by stress preadaptation and overexpression of stress adaptation genes.
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Affiliation(s)
- Pengyu Wu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Zhaopu Wang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Qiuyan Zhu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Zhixiong Xie
- College of Life Science, Wuhan University, Wuhan, 430072, PR China.
| | - Yuxia Mei
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Yunxiang Liang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Zhenmin Chen
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, PR China.
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9
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Expression and function of the cdgD gene, encoding a CHASE-PAS-DGC-EAL domain protein, in Azospirillum brasilense. Sci Rep 2021; 11:520. [PMID: 33436847 PMCID: PMC7804937 DOI: 10.1038/s41598-020-80125-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 12/17/2020] [Indexed: 02/06/2023] Open
Abstract
The plant growth-promoting bacterium Azospirillum brasilense contains several genes encoding proteins involved in the biosynthesis and degradation of the second messenger cyclic-di-GMP, which may control key bacterial functions, such as biofilm formation and motility. Here, we analysed the function and expression of the cdgD gene, encoding a multidomain protein that includes GGDEF-EAL domains and CHASE and PAS domains. An insertional cdgD gene mutant was constructed, and analysis of biofilm and extracellular polymeric substance production, as well as the motility phenotype indicated that cdgD encoded a functional diguanylate protein. These results were correlated with a reduced overall cellular concentration of cyclic-di-GMP in the mutant over 48 h compared with that observed in the wild-type strain, which was recovered in the complemented strain. In addition, cdgD gene expression was measured in cells growing under planktonic or biofilm conditions, and differential expression was observed when KNO3 or NH4Cl was added to the minimal medium as a nitrogen source. The transcriptional fusion of the cdgD promoter with the gene encoding the autofluorescent mCherry protein indicated that the cdgD gene was expressed both under abiotic conditions and in association with wheat roots. Reduced colonization of wheat roots was observed for the mutant compared with the wild-type strain grown in the same soil conditions. The Azospirillum-plant association begins with the motility of the bacterium towards the plant rhizosphere followed by the adsorption and adherence of these bacteria to plant roots. Therefore, it is important to study the genes that contribute to this initial interaction of the bacterium with its host plant.
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Zboralski A, Filion M. Genetic factors involved in rhizosphere colonization by phytobeneficial Pseudomonas spp. Comput Struct Biotechnol J 2020; 18:3539-3554. [PMID: 33304453 PMCID: PMC7711191 DOI: 10.1016/j.csbj.2020.11.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/10/2020] [Accepted: 11/12/2020] [Indexed: 12/13/2022] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) actively colonize the soil portion under the influence of plant roots, called the rhizosphere. Many plant-beneficial Pseudomonas spp. have been characterized as PGPR. They are ubiquitous rod-shaped motile Gram-negative bacteria displaying a high metabolic versatility. Their capacity to protect plants from pathogens and improve plant growth closely depends on their rhizosphere colonization abilities. Various molecular and cellular mechanisms are involved in this complex process, such as chemotaxis, biofilm formation, secondary metabolites biosynthesis, metabolic versatility, and evasion of plant immunity. The burst in Pseudomonas spp. genome sequencing in recent years has been crucial to better understand how they colonize the rhizosphere. In this review, we discuss the recent advances regarding these mechanisms and the underlying bacterial genetic factors required for successful rhizosphere colonization.
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Affiliation(s)
- Antoine Zboralski
- Department of Biology, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Martin Filion
- Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada
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Grenga L, Little RH, Chandra G, Woodcock SD, Saalbach G, Morris RJ, Malone JG. Control of mRNA translation by dynamic ribosome modification. PLoS Genet 2020; 16:e1008837. [PMID: 32584816 PMCID: PMC7343187 DOI: 10.1371/journal.pgen.1008837] [Citation(s) in RCA: 5] [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: 05/04/2020] [Revised: 07/08/2020] [Accepted: 05/07/2020] [Indexed: 01/28/2023] Open
Abstract
Control of mRNA translation is a crucial regulatory mechanism used by bacteria to respond to their environment. In the soil bacterium Pseudomonas fluorescens, RimK modifies the C-terminus of ribosomal protein RpsF to influence important aspects of rhizosphere colonisation through proteome remodelling. In this study, we show that RimK activity is itself under complex, multifactorial control by the co-transcribed phosphodiesterase trigger enzyme (RimA) and a polyglutamate-specific protease (RimB). Furthermore, biochemical experimentation and mathematical modelling reveal a role for the nucleotide second messenger cyclic-di-GMP in coordinating these activities. Active ribosome regulation by RimK occurs by two main routes: indirectly, through changes in the abundance of the global translational regulator Hfq and directly, with translation of surface attachment factors, amino acid transporters and key secreted molecules linked specifically to RpsF modification. Our findings show that post-translational ribosomal modification functions as a rapid-response mechanism that tunes global gene translation in response to environmental signals.
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Affiliation(s)
- Lucia Grenga
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
| | | | - Govind Chandra
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | | | - Gerhard Saalbach
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | - Richard James Morris
- Computational and Systems Biology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | - Jacob George Malone
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
- * E-mail:
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Thompson CM, Malone JG. Nucleotide second messengers in bacterial decision making. Curr Opin Microbiol 2020; 55:34-39. [PMID: 32172083 PMCID: PMC7322531 DOI: 10.1016/j.mib.2020.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/04/2020] [Accepted: 02/10/2020] [Indexed: 12/28/2022]
Abstract
Structural analysis of NSM regulators reveals new mechanisms of NSM signalling. NSM proteins binding multiple ligands support crosstalk between signalling networks. NSM networks control structure and heterogeneity in complex microbial communities. The diversity of bacterial NSM regulators is far higher than previously thought. The (p)ppApp toxin suggests non-signalling roles exist for bacterial NSMs.
Since the initial discovery of bacterial nucleotide second messengers (NSMs), we have made huge progress towards understanding these complex signalling networks. Many NSM networks contain dozens of metabolic enzymes and binding targets, whose activity is tightly controlled at every regulatory level. They function as global regulators and in specific signalling circuits, controlling multiple aspects of bacterial behaviour and development. Despite these advances there is much still to discover, with current research focussing on the molecular mechanisms of signalling circuits, the role of the environment in controlling NSM pathways and attempts to understand signalling at the whole cell/community level. Here we examine recent developments in the NSM signalling field and discuss their implications for understanding this important driver of microbial behaviour.
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Affiliation(s)
- Catriona Ma Thompson
- Molecular Microbiology Department, John Innes Centre, Norwich, UK; School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Jacob G Malone
- Molecular Microbiology Department, John Innes Centre, Norwich, UK; School of Biological Sciences, University of East Anglia, Norwich, UK.
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Noirot-Gros MF, Forrester S, Malato G, Larsen PE, Noirot P. CRISPR interference to interrogate genes that control biofilm formation in Pseudomonas fluorescens. Sci Rep 2019; 9:15954. [PMID: 31685917 PMCID: PMC6828691 DOI: 10.1038/s41598-019-52400-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 10/12/2019] [Indexed: 12/11/2022] Open
Abstract
Bacterial biofilm formation involves signaling and regulatory pathways that control the transition from motile to sessile lifestyle, production of extracellular polymeric matrix, and maturation of the biofilm 3D structure. Biofilms are extensively studied because of their importance in biomedical, ecological and industrial settings. Gene inactivation is a powerful approach for functional studies but it is often labor intensive, limiting systematic gene surveys to the most tractable bacterial hosts. Here, we adapted the CRISPR interference (CRISPRi) system for use in diverse strain isolates of P. fluorescens, SBW25, WH6 and Pf0-1. We found that CRISPRi is applicable to study complex phenotypes such as cell morphology, motility and biofilm formation over extended periods of time. In SBW25, CRISPRi-mediated silencing of genes encoding the GacA/S two-component system and regulatory proteins associated with the cylic di-GMP signaling messenger produced swarming and biofilm phenotypes similar to those obtained after gene inactivation. Combined with detailed confocal microscopy of biofilms, our study also revealed novel phenotypes associated with extracellular matrix biosynthesis as well as the potent inhibition of SBW25 biofilm formation mediated by the PFLU1114 operon. We conclude that CRISPRi is a reliable and scalable approach to investigate gene networks in the diverse P. fluorescens group.
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Affiliation(s)
| | - Sara Forrester
- Biosciences Division, Argonne National Laboratory, Lemont, IL60439, United States
| | - Grace Malato
- Biosciences Division, Argonne National Laboratory, Lemont, IL60439, United States
| | - Peter E Larsen
- Biosciences Division, Argonne National Laboratory, Lemont, IL60439, United States.,Department of Bioengineering, University of Illinois Chicago, Chicago, IL60607, United States
| | - Philippe Noirot
- Biosciences Division, Argonne National Laboratory, Lemont, IL60439, United States
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