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Maguvu TE, Frias RJ, Hernandez-Rosas AI, Holtz BA, Niederholzer FJA, Duncan RA, Yaghmour MA, Culumber CM, Gordon PE, Vieira FCF, Rolshausen PE, Adaskaveg JE, Burbank LP, Lindow SE, Trouillas FP. Phylogenomic analyses and comparative genomics of Pseudomonas syringae associated with almond (Prunus dulcis) in California. PLoS One 2024; 19:e0297867. [PMID: 38603730 PMCID: PMC11008872 DOI: 10.1371/journal.pone.0297867] [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: 11/22/2023] [Accepted: 01/10/2024] [Indexed: 04/13/2024] Open
Abstract
We sequenced and comprehensively analysed the genomic architecture of 98 fluorescent pseudomonads isolated from different symptomatic and asymptomatic tissues of almond and a few other Prunus spp. Phylogenomic analyses, genome mining, field pathogenicity tests, and in vitro ice nucleation and antibiotic sensitivity tests were integrated to improve knowledge of the biology and management of bacterial blast and bacterial canker of almond. We identified Pseudomonas syringae pv. syringae, P. cerasi, and P. viridiflava as almond canker pathogens. P. syringae pv. syringae caused both canker and foliar (blast) symptoms. In contrast, P. cerasi and P. viridiflava only caused cankers, and P. viridiflava appeared to be a weak pathogen of almond. Isolates belonging to P. syringae pv. syringae were the most frequently isolated among the pathogenic species/pathovars, composing 75% of all pathogenic isolates. P. cerasi and P. viridiflava isolates composed 8.3 and 16.7% of the pathogenic isolates, respectively. Laboratory leaf infiltration bioassays produced results distinct from experiments in the field with both P. cerasi and P. syringae pv. syringae, causing significant necrosis and browning of detached leaves, whereas P. viridiflava conferred moderate effects. Genome mining revealed the absence of key epiphytic fitness-related genes in P. cerasi and P. viridiflava genomic sequences, which could explain the contrasting field and laboratory bioassay results. P. syringae pv. syringae and P. cerasi isolates harboured the ice nucleation protein, which correlated with the ice nucleation phenotype. Results of sensitivity tests to copper and kasugamycin showed a strong linkage to putative resistance genes. Isolates harbouring the ctpV gene showed resistance to copper up to 600 μg/ml. In contrast, isolates without the ctpV gene could not grow on nutrient agar amended with 200 μg/ml copper, suggesting ctpV can be used to phenotype copper resistance. All isolates were sensitive to kasugamycin at the label-recommended rate of 100μg/ml.
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Affiliation(s)
- Tawanda E. Maguvu
- Department of Plant Pathology, University of California, Davis, Davis, CA, United States of America
- Kearney Agricultural Research and Extension Center, Parlier, CA, United States of America
| | - Rosa J. Frias
- Department of Plant Pathology, University of California, Davis, Davis, CA, United States of America
| | | | - Brent A. Holtz
- University of California Cooperative Extension, CA, United States of America
| | | | - Roger A. Duncan
- University of California Cooperative Extension, CA, United States of America
| | | | | | - Phoebe E. Gordon
- University of California Cooperative Extension, CA, United States of America
| | - Flavia C. F. Vieira
- Department of Plant Pathology and Microbiology, University of California, Riverside, Riverside, CA, United States of America
| | - Philippe E. Rolshausen
- Department of Plant Pathology and Microbiology, University of California, Riverside, Riverside, CA, United States of America
| | - James E. Adaskaveg
- Department of Plant Pathology and Microbiology, University of California, Riverside, Riverside, CA, United States of America
| | - Lindsey P. Burbank
- U.S. Department of Agriculture, Agricultural Research Service, Parlier, CA, United States of America
| | - Steven E. Lindow
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States of America
| | - Florent P. Trouillas
- Department of Plant Pathology, University of California, Davis, Davis, CA, United States of America
- Kearney Agricultural Research and Extension Center, Parlier, CA, United States of America
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Guo Q, Su J, Liao Y, Yu Y, Luo L, Weng X, Zhang W, Hu Z, Wang H, Beattie GA, Ma J. An atypical 3-ketoacyl ACP synthase III required for acyl homoserine lactone synthesis in Pseudomonas syringae pv. syringae B728a. Appl Environ Microbiol 2024; 90:e0225623. [PMID: 38415624 PMCID: PMC10952384 DOI: 10.1128/aem.02256-23] [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: 12/13/2023] [Accepted: 02/04/2024] [Indexed: 02/29/2024] Open
Abstract
The last step of the initiation phase of fatty acid biosynthesis in most bacteria is catalyzed by the 3-ketoacyl-acyl carrier protein (ACP) synthase III (FabH). Pseudomonas syringae pv. syringae strain B728a encodes two FabH homologs, Psyr_3467 and Psyr_3830, which we designated PssFabH1 and PssFabH2, respectively. Here, we explored the roles of these two 3-ketoacyl-ACP synthase (KAS) III proteins. We found that PssFabH1 is similar to the Escherichia coli FabH in using acetyl-acetyl-coenzyme A (CoA ) as a substrate in vitro, whereas PssFabH2 uses acyl-CoAs (C4-C10) or acyl-ACPs (C6-C10). Mutant analysis showed that neither KAS III protein is essential for the de novo fatty acid synthesis and cell growth. Loss of PssFabH1 reduced the production of an acyl homoserine lactone (AHL) quorum-sensing signal, and this production was partially restored by overexpressing FabH homologs from other bacteria. AHL production was also restored by inhibiting fatty acid elongation and providing exogenous butyric acid. Deletion of PssFabH1 supports the redirection of acyl-ACP toward biosurfactant synthesis, which in turn enhances swarming motility. Our study revealed that PssFabH1 is an atypical KAS III protein that represents a new KAS III clade that functions in providing a critical fatty acid precursor, butyryl-ACP, for AHL synthesis.IMPORTANCEAcyl homoserine lactones (AHLs) are important quorum-sensing compounds in Gram-negative bacteria. Although their formation requires acylated acyl carrier proteins (ACPs), how the acylated intermediate is shunted from cellular fatty acid synthesis to AHL synthesis is not known. Here, we provide in vivo evidence that Pseudomonas syringae strain B728a uses the enzyme PssFabH1 to provide the critical fatty acid precursor butyryl-ACP for AHL synthesis. Loss of PssFabH1 reduces the diversion of butyryl-ACP to AHL, enabling the accumulation of acyl-ACP for synthesis of biosurfactants that contribute to bacterial swarming motility. We report that PssFabH1 and PssFabH2 each encode a 3-ketoacyl-acyl carrier protein synthase (KAS) III in P. syringae B728a. Whereas PssFabH2 is able to function in redirecting intermediates from β-oxidation to fatty acid synthesis, PssFabH1 is an atypical KAS III protein that represents a new KAS III clade based on its sequence, non-involvement in cell growth, and novel role in AHL synthesis.
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Affiliation(s)
- Qiaoqiao Guo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Jingtong Su
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yuling Liao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yin Yu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Lizhen Luo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xiaoshan Weng
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Wenbin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Gwyn A. Beattie
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa, USA
| | - Jincheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa, USA
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Johnson JMB, Kunkel BN. AefR, a TetR Family Transcriptional Repressor, Regulates Several Auxin Responses in Pseudomonas syringae Strain PtoDC3000. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:155-165. [PMID: 38079389 DOI: 10.1094/mpmi-10-23-0170-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
The plant hormone indole-3-acetic acid (IAA), also known as auxin, plays important roles in plant growth and development, as well as in several plant-microbe interactions. IAA also acts as a microbial signal and in many bacteria regulates metabolism, stress responses, and virulence. In the bacterial plant pathogen Pseudomonas syringae pv. tomato strain DC3000 (PtoDC3000), exposure to IAA results in large-scale transcriptional reprogramming, including the differential expression of several known virulence genes. However, how PtoDC3000 senses and responds to IAA and what aspects of its biology are regulated by IAA is not understood. To investigate the mechanisms involved in perceiving and responding to IAA, we carried out a genetic screen for mutants with altered responses to IAA. One group of mutants of particular interest carried disruptions in the aefR gene encoding a TetR family transcriptional regulator. Gene expression analysis confirmed that the aefR mutants have altered responses to IAA. Thus, AefR is the first demonstrated auxin response regulator in PtoDC3000. We also investigated several aspects of PtoDC3000 biology that are regulated by both AefR and IAA, including antibiotic resistance, motility, and virulence. The observation that the aefR mutant has altered virulence on Arabidopsis, suggests that the sector of the IAA response regulated by aefR is important during pathogenesis. Our findings also provide evidence that AefR plays a role in coordinating changes in gene expression during the transition from early to late stages of infection. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Joshua M B Johnson
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
| | - Barbara N Kunkel
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
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Ivanović M, Prokić A, Gašić K, Menković J, Kuzmanović N, Zlatković N, Obradović A. Characterization of Pseudomonas syringae Strains Associated with Shoot Blight of Raspberry and Blackberry in Serbia. PLANT DISEASE 2023; 107:826-833. [PMID: 35952382 DOI: 10.1094/pdis-06-22-1425-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
During May 2016, severe blight symptoms were observed in several raspberry and blackberry fields in Serbia. In total, 22 strains were isolated: 16 from symptomatic raspberry shoots, 2 from asymptomatic raspberry leaves, and 4 from symptomatic blackberry shoots. Additionally, eight raspberry strains, isolated earlier from two similar outbreaks, were included in the study. Pathogenicity of the strains was confirmed on detached raspberry and blackberry shoots by reproducing the symptoms of natural infection. The strains were Gram-negative, fluorescent on King's medium B, ice nucleation positive, and utilized glucose oxidatively. All strains were levan positive, oxidase negative, nonpectolytic, arginine dihydrolase negative, and induced hypersensitivity in tobacco leaves (LOPAT + - - - +, Pseudomonas group Ia). Furthermore, all strains liquefied gelatin and hydrolyzed aesculin but did not show tyrosinase activity or utilize tartrate (GATTa + + - -). Tentative identification using morphology, LOPAT, GATTa, and ice-nucleating ability tests suggested that isolated strains belong to Pseudomonas syringae. The syrB gene associated with syringomycin production was detected in all strains. DNA fingerprints with REP, ERIC, and BOX primers generated identical profiles for 29 strains, except for strain KBI 222, which showed a unique genomic fingerprint. In all, 9 of 10 selected strains exhibited identical sequences of four housekeeping genes: gyrB, rpoD, gapA, and gltA. Five nucleotide polymorphisms were found in strain KBI 222 at the rpoD gene locus only. In the phylogenetic tree based on a concatenated sequence of all four housekeeping genes, strains clustered within phylogroup 2 (i.e., genomospecies 1) of the P. syringae species complex, with pathotype strains of P. syringae pv. aceris and P. syringae pv. solidagae as their closest relatives. There was no correlation between genotype and geographic origin, particular outbreak, host, or cultivar.
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Affiliation(s)
- Milan Ivanović
- University of Belgrade-Faculty of Agriculture, 11080 Belgrade-Zemun, Serbia
| | - Anđelka Prokić
- University of Belgrade-Faculty of Agriculture, 11080 Belgrade-Zemun, Serbia
| | - Katarina Gašić
- Institute for Plant Protection and Environment, 11040 Belgrade, Serbia
| | - Jelena Menković
- University of Belgrade-Faculty of Agriculture, 11080 Belgrade-Zemun, Serbia
| | - Nemanja Kuzmanović
- Institute for Plant Protection in Horticulture and Forests, Federal Research Centre for Cultivated Plants, Julius Kühn Institute, 38104 Braunschweig, Germany
| | - Nevena Zlatković
- Institute for Plant Protection and Environment, 11040 Belgrade, Serbia
| | - Aleksa Obradović
- University of Belgrade-Faculty of Agriculture, 11080 Belgrade-Zemun, Serbia
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Virulence-related regulatory network of Pseudomonas syringae. Comput Struct Biotechnol J 2022; 20:6259-6270. [DOI: 10.1016/j.csbj.2022.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 11/05/2022] [Accepted: 11/05/2022] [Indexed: 11/11/2022] Open
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Identification of IAA-regulated genes in Pseudomonas syringae pv. tomato strain DC3000. J Bacteriol 2021; 204:e0038021. [PMID: 34662236 DOI: 10.1128/jb.00380-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 (PtoDC3000). To learn more about the impact of IAA on regulation of PtoDC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta. Collectively the data indicate that IAA modulates many aspects of PtoDC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain PtoDC000 and one of its hosts, Arabidopsis thaliana. However, the mechanisms by which IAA impacts the biology of PtoDC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in PtoDC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.
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O’Malley MR, Anderson JC. Regulation of the Pseudomonas syringae Type III Secretion System by Host Environment Signals. Microorganisms 2021; 9:microorganisms9061227. [PMID: 34198761 PMCID: PMC8228185 DOI: 10.3390/microorganisms9061227] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas syringae are Gram-negative, plant pathogenic bacteria that use a type III secretion system (T3SS) to disarm host immune responses and promote bacterial growth within plant tissues. Despite the critical role for type III secretion in promoting virulence, T3SS-encoding genes are not constitutively expressed by P. syringae and must instead be induced during infection. While it has been known for many years that culturing P. syringae in synthetic minimal media can induce the T3SS, relatively little is known about host signals that regulate the deployment of the T3SS during infection. The recent identification of specific plant-derived amino acids and organic acids that induce T3SS-inducing genes in P. syringae has provided new insights into host sensing mechanisms. This review summarizes current knowledge of the regulatory machinery governing T3SS deployment in P. syringae, including master regulators HrpRS and HrpL encoded within the T3SS pathogenicity island, and the environmental factors that modulate the abundance and/or activity of these key regulators. We highlight putative receptors and regulatory networks involved in linking the perception of host signals to the regulation of the core HrpRS–HrpL pathway. Positive and negative regulation of T3SS deployment is also discussed within the context of P. syringae infection, where contributions from distinct host signals and regulatory networks likely enable the fine-tuning of T3SS deployment within host tissues. Last, we propose future research directions necessary to construct a comprehensive model that (a) links the perception of host metabolite signals to T3SS deployment and (b) places these host–pathogen signaling events in the overall context of P. syringae infection.
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Friends or Foes-Microbial Interactions in Nature. BIOLOGY 2021; 10:biology10060496. [PMID: 34199553 PMCID: PMC8229319 DOI: 10.3390/biology10060496] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 05/27/2021] [Accepted: 05/31/2021] [Indexed: 12/16/2022]
Abstract
Simple Summary Microorganisms like bacteria, archaea, fungi, microalgae, and viruses mostly form complex interactive networks within the ecosystem rather than existing as single planktonic cells. Interactions among microorganisms occur between the same species, with different species, or even among entirely different genera, families, or even domains. These interactions occur after environmental sensing, followed by converting those signals to molecular and genetic information, including many mechanisms and classes of molecules. Comprehensive studies on microbial interactions disclose key strategies of microbes to colonize and establish in a variety of different environments. Knowledge of the mechanisms involved in the microbial interactions is essential to understand the ecological impact of microbes and the development of dysbioses. It might be the key to exploit strategies and specific agents against different facing challenges, such as chronic and infectious diseases, hunger crisis, pollution, and sustainability. Abstract Microorganisms are present in nearly every niche on Earth and mainly do not exist solely but form communities of single or mixed species. Within such microbial populations and between the microbes and a eukaryotic host, various microbial interactions take place in an ever-changing environment. Those microbial interactions are crucial for a successful establishment and maintenance of a microbial population. The basic unit of interaction is the gene expression of each organism in this community in response to biotic or abiotic stimuli. Differential gene expression is responsible for producing exchangeable molecules involved in the interactions, ultimately leading to community behavior. Cooperative and competitive interactions within bacterial communities and between the associated bacteria and the host are the focus of this review, emphasizing microbial cell–cell communication (quorum sensing). Further, metagenomics is discussed as a helpful tool to analyze the complex genomic information of microbial communities and the functional role of different microbes within a community and to identify novel biomolecules for biotechnological applications.
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Morohoshi T, Oshima A, Xie X, Someya N. Genetic and functional diversity of PsyI/PsyR quorum-sensing system in the Pseudomonas syringae complex. FEMS Microbiol Ecol 2021; 97:6041021. [PMID: 33332533 DOI: 10.1093/femsec/fiaa254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 12/15/2020] [Indexed: 11/13/2022] Open
Abstract
Strains belonging to the Pseudomonas syringae complex often possess quorum-sensing systems that comprise N-acyl-l-homoserine lactone (AHL) synthases (PsyI) and AHL receptors (PsyR). Here, we investigated the diversity of PsyI/PsyR quorum-sensing systems in 630 strains of the P. syringae complex. AHL production was observed in most strains of Pseudomonas amygdali and Pseudomonas meliae, and a few strains of Pseudomonas coronafaciens and P. syringae. The DNA sequences of psyIR and their upstream and downstream regions were categorized into eight types. P. amygdali pv. myricae, Pseudomonas savastanoi, and P. syringae pv. solidagae, maculicola, broussonetiae, and tomato encoded psyI, but did not produce detectable amounts of AHL. In P. savastanoi, an amino acid substitution (R27S) in PsyI caused defective AHL production. The psyI gene of P. syringae pv. tomato was converted to pseudogenes by frameshift mutations. Escherichia coli harboring psyI genes from P. amygdali pv. myricae, P. syringae pv. solidagae and broussonetiae showed high levels of AHL production. Forced expression of functional psyR restored AHL production in P. amygdali pv. myricae and P. syringae pv. solidagae. In conclusion, our study indicates that the PsyI/PsyR quorum-sensing systems in P. syringae strains are genetically and functionally diverse, with diversity being linked to phylogenetic and pathovar classifications.
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Affiliation(s)
- Tomohiro Morohoshi
- Graduate School of Regional Development and Creativity, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi 321-8585, Japan
| | - Akinori Oshima
- Graduate School of Regional Development and Creativity, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi 321-8585, Japan
| | - Xiaonan Xie
- Center for Bioscience Research and Education, Utsunomiya University, 350 Mine-machi, Utsunomiya, Tochigi 321-8505, Japan
| | - Nobutaka Someya
- Institute of Vegetable and Floriculture Science, National Agriculture and Food Research Organization, 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8519, Japan
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Shao X, Tan M, Xie Y, Yao C, Wang T, Huang H, Zhang Y, Ding Y, Liu J, Han L, Hua C, Wang X, Deng X. Integrated regulatory network in Pseudomonas syringae reveals dynamics of virulence. Cell Rep 2021; 34:108920. [PMID: 33789108 DOI: 10.1016/j.celrep.2021.108920] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/09/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas syringae, a Gram-negative plant pathogen, expresses multitudinous transcriptional regulators to control the type III secretion system (T3SS) and response to diverse environmental challenges. Although the mechanisms of virulence-associated regulators of P. syringae have been studied for decades, the overall crosstalk underlying these regulators is still elusive. Here, we identify five T3SS regulators (EnvZ-OmpR, CbrAB2, PhoPQ, PilRS, and MgrA), and find that the two-component systems EnvZ-OmpR and CbrAB2 negatively regulate the T3SS. To elucidate crosstalk between 16 virulence-associated regulators in P. syringae, we map an online intricate network called "PSRnet" (Pseudomonas syringae regulatory network) by combining the differentially expressed genes (DEGs) of these 16 regulators by RNA sequencing (RNA-seq) and their binding loci by chromatin immunoprecipitation sequencing (ChIP-seq). Consequently, we identify 238 and 153 functional genes involved in the T3SS and other virulence-related pathways in KB and MM media, respectively. Our results provide insights into the mechanism of plant infections caused by P. syringae.
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Affiliation(s)
- Xiaolong Shao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Miaomiao Tan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yingpeng Xie
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Chunyan Yao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Tingting Wang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Hao Huang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yingchao Zhang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yiqing Ding
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Jingui Liu
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Liangliang Han
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Canfeng Hua
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Xin Wang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China.
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China.
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11
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Quorum Sensing Regulation in Phytopathogenic Bacteria. Microorganisms 2021; 9:microorganisms9020239. [PMID: 33498890 PMCID: PMC7912708 DOI: 10.3390/microorganisms9020239] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 11/17/2022] Open
Abstract
Quorum sensing is a type of chemical communication by which bacterial populations control expression of their genes in a coordinated manner. This regulatory mechanism is commonly used by pathogens to control the expression of genes encoding virulence factors and that of genes involved in the bacterial adaptation to variations in environmental conditions. In phytopathogenic bacteria, several mechanisms of quorum sensing have been characterized. In this review, we describe the different quorum sensing systems present in phytopathogenic bacteria, such as those using the signal molecules named N-acyl-homoserine lactone (AHL), diffusible signal factor (DSF), and the unknown signal molecule of the virulence factor modulating (VFM) system. We focus on studies performed on phytopathogenic bacteria of major importance, including Pseudomonas, Ralstonia, Agrobacterium, Xanthomonas, Erwinia, Xylella,Dickeya, and Pectobacterium spp. For each system, we present the mechanism of regulation, the functions targeted by the quorum sensing system, and the mechanisms by which quorum sensing is regulated.
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12
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Xie Y, Liu W, Shao X, Zhang W, Deng X. Signal transduction schemes in Pseudomonas syringae. Comput Struct Biotechnol J 2020; 18:3415-3424. [PMID: 33294136 PMCID: PMC7691447 DOI: 10.1016/j.csbj.2020.10.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/29/2020] [Accepted: 10/31/2020] [Indexed: 11/11/2022] Open
Abstract
To cope with their continually fluctuating surroundings, pathovars of the unicellular phytopathogen Pseudomonas syringae have developed rapid and sophisticated signalling networks to sense extracellular stimuli, which allow them to adjust their cellular composition to survive and cause diseases in host plants. Comparative genomic analyses of P. syringae strains have identified various genes that encode several classes of signalling proteins, although how this bacterium directly perceives these environmental cues remains elusive. Recent work has revealed new mechanisms of a cluster of bacterial signal transduction systems that mainly include two-component systems (such as RhpRS, GacAS, CvsRS and AauRS), extracytoplasmic function sigma factors (such as HrpL and AlgU), nucleotide-based secondary messengers, methyl-accepting chemotaxis sensor proteins and several other intracellular surveillance systems. In this review, we compile a list of the signal transduction mechanisms that P. syringae uses to monitor and respond in a timely manner to intracellular and external conditions. Further understanding of these surveillance processes will provide new perspectives from which to combat P. syringae infections.
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Affiliation(s)
- Yingpeng Xie
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region
| | - Wenbao Liu
- College of Agricultural Sciences and Technology, Shandong Agriculture and Engineering University, Jinan 250100, China
| | - Xiaolong Shao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region
| | - Weihua Zhang
- Institute of Vegetables and Flowers, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region.,Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
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Abdul Malik SA, Bazire A, Gamboa-Muñoz A, Bedoux G, Robledo D, García-Maldonado JQ, Bourgougnon N. Screening of Surface-associated Bacteria from the Mexican Red Alga Halymenia floresii for Quorum Sensing Activity. Microbiology (Reading) 2020. [DOI: 10.1134/s0026261720060132] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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14
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A compendium of DNA-binding specificities of transcription factors in Pseudomonas syringae. Nat Commun 2020; 11:4947. [PMID: 33009392 PMCID: PMC7532196 DOI: 10.1038/s41467-020-18744-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 09/08/2020] [Indexed: 11/23/2022] Open
Abstract
Pseudomonas syringae is a Gram-negative and model pathogenic bacterium that causes plant diseases worldwide. Here, we set out to identify binding motifs for all 301 annotated transcription factors (TFs) of P. syringae using HT-SELEX. We successfully identify binding motifs for 100 TFs. We map functional interactions between the TFs and their targets in virulence-associated pathways, and validate many of these interactions and functions using additional methods such as ChIP-seq, electrophoretic mobility shift assay (EMSA), RT-qPCR, and reporter assays. Our work identifies 25 virulence-associated master regulators, 14 of which had not been characterized as TFs before. The authors set out to identify binding motifs for all 301 transcription factors of a plant pathogenic bacterium, Pseudomonas syringae, using HT-SELEX. They successfully identify binding motifs for 100 transcription factors, infer their binding sites on the genome, and validate the predicted interactions and functions.
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15
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Tran TM, Ma Z, Triebl A, Nath S, Cheng Y, Gong BQ, Han X, Wang J, Li JF, Wenk MR, Torta F, Mayor S, Yang L, Miao Y. The bacterial quorum sensing signal DSF hijacks Arabidopsis thaliana sterol biosynthesis to suppress plant innate immunity. Life Sci Alliance 2020; 3:e202000720. [PMID: 32788227 PMCID: PMC7425213 DOI: 10.26508/lsa.202000720] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 07/26/2020] [Accepted: 07/30/2020] [Indexed: 01/04/2023] Open
Abstract
Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS molecules on host biology is largely understudied. In this work, we show that the QS molecule DSF (cis-11-methyl-dodecenoic acid) produced by Xanthomonas campestris pv. campestris can suppress pathogen-associated molecular pattern-triggered immunity (PTI) in Arabidopsis thaliana, mediated by flagellin-induced activation of flagellin receptor FLS2. The DSF-mediated attenuation of innate immunity results from the alteration of FLS2 nanoclusters and endocytic internalization of plasma membrane FLS2. DSF altered the lipid profile of Arabidopsis, with a particular increase in the phytosterol species, which impairs the general endocytosis pathway mediated by clathrin and FLS2 nano-clustering on the plasma membrane. The DSF effect on receptor dynamics and host immune responses could be entirely reversed by sterol removal. Together, our results highlighted the importance of sterol homeostasis to plasma membrane organization and demonstrate a novel mechanism by which pathogenic bacteria use their communicating molecule to manipulate pathogen-associated molecular pattern-triggered host immunity.
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Affiliation(s)
- Tuan Minh Tran
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Alexander Triebl
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sangeeta Nath
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Bangalore, India
| | - Yingying Cheng
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Ben-Qiang Gong
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Junqi Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Jian-Feng Li
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Markus R Wenk
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Federico Torta
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Satyajit Mayor
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
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16
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Tran TM, Ma Z, Triebl A, Nath S, Cheng Y, Gong BQ, Han X, Wang J, Li JF, Wenk MR, Torta F, Mayor S, Yang L, Miao Y. The bacterial quorum sensing signal DSF hijacks Arabidopsis thaliana sterol biosynthesis to suppress plant innate immunity. Life Sci Alliance 2020. [PMID: 32788227 DOI: 10.1101/927731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS molecules on host biology is largely understudied. In this work, we show that the QS molecule DSF (cis-11-methyl-dodecenoic acid) produced by Xanthomonas campestris pv. campestris can suppress pathogen-associated molecular pattern-triggered immunity (PTI) in Arabidopsis thaliana, mediated by flagellin-induced activation of flagellin receptor FLS2. The DSF-mediated attenuation of innate immunity results from the alteration of FLS2 nanoclusters and endocytic internalization of plasma membrane FLS2. DSF altered the lipid profile of Arabidopsis, with a particular increase in the phytosterol species, which impairs the general endocytosis pathway mediated by clathrin and FLS2 nano-clustering on the plasma membrane. The DSF effect on receptor dynamics and host immune responses could be entirely reversed by sterol removal. Together, our results highlighted the importance of sterol homeostasis to plasma membrane organization and demonstrate a novel mechanism by which pathogenic bacteria use their communicating molecule to manipulate pathogen-associated molecular pattern-triggered host immunity.
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Affiliation(s)
- Tuan Minh Tran
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Alexander Triebl
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sangeeta Nath
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Bangalore, India
| | - Yingying Cheng
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Ben-Qiang Gong
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Junqi Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Jian-Feng Li
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Markus R Wenk
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Federico Torta
- Department of Biochemistry, Singapore Lipidomics Incubator (SLING), Yoo Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Satyajit Mayor
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
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17
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Physiological Advantage of Phenotypic Heterogeneity in a Quorum-Sensing Population. J Indian Inst Sci 2020. [DOI: 10.1007/s41745-020-00175-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Ling J, Zhou L, Wu G, Zhao Y, Jiang T, Liu F. The AHL Quorum-Sensing System Negatively Regulates Growth and Autolysis in Lysobacter brunescens. Front Microbiol 2019; 10:2748. [PMID: 31849892 PMCID: PMC6902743 DOI: 10.3389/fmicb.2019.02748] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 11/12/2019] [Indexed: 11/13/2022] Open
Abstract
Lysobacter species are emerging as novel sources of antibiotics, but the regulation of their physiological metabolism is still poorly understood. In this work, we extracted AHL (acyl-homoserine lactone) autoinducers, identified the structures of AHLs and described the AHL quorum-sensing system in Lysobacter brunescens OH23. AHLs were isolated from the supernatant of L. brunescens OH23, and ESI-MS/MS (electrospray ionization mass spectrometry) analysis revealed biosynthesis of three different AHL chemical structures by L. brunescens OH23: N-(3-oxohexanoyl)- homoserine lactone (HSL), 3-OH-C10-HSL and C8-HSL. The growth rate of AHL quorum-sensing knockout mutants was dramatically increased compared to that of wildtype. Sucrose consumptions were also twice as high in AHL quorum-sensing knockout mutants than that in wildtype in early-log phase. Additionally, expression of key genes related to sucrose metabolism α-glucosidase was enhanced in AHL quorum-sensing knockout mutants, which indicated that AHL quorum sensing negatively regulates sucrose uptake and metabolism which further affects the growth rate of L. brunescens. Furthermore, autolysis was strongly induced in AHL quorum-sensing knockout mutants compared to wildtype, suggesting that AHL quorum sensing plays a negative regulatory role in cell autolysis. Moreover, compared to wildtype, XSAC (Xanthomonas-specific antibiotic compound) production was significantly increased in AHL knockout mutants in the early-log and late-log phases, and surface motility capabilities are also enhanced also in AHL knockout mutants; the normalized data of XSAC production and surface motility and expressions of key genes related to these two phenotypes reveal that growth rare and autolysis strongly affects XSAC biosynthesis and surface motility rather than AHL quorum-sensing system. Our results show that the AHL quorum-sensing system negatively regulates cell growth and autolysis, and further maintain nutrition homeostasis and population stability in L. brunescens.
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Affiliation(s)
- Jun Ling
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Lan Zhou
- Academy of Agricultural Sciences of Yanbian, Longjing, China
| | - Guichun Wu
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yancun Zhao
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Tianping Jiang
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Fengquan Liu
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
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19
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Su P, Zhang D, Zhang Z, Chen A, Hamid MR, Li C, Du J, Cheng J, Tan X, Zhen L, Zhai Z, Tang W, Chen J, Zhou X, Liu Y. Characterization of Rhodopseudomonas palustris population dynamics on tobacco phyllosphere and induction of plant resistance to Tobacco mosaic virus. Microb Biotechnol 2019; 12:1453-1463. [PMID: 31566880 PMCID: PMC6801143 DOI: 10.1111/1751-7915.13486] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/16/2019] [Accepted: 08/26/2019] [Indexed: 11/29/2022] Open
Abstract
Although many biocontrol bacteria can be used to improve plant tolerance to stresses and to promote plant growth, the hostile environmental conditions on plant phyllosphere and the limited knowledge on bacterial colonization on plant phyllosphere minimized the beneficial effects produced by the biocontrol bacteria. Rhodopseudomonas palustris strain GJ-22 is known as a phyllosphere biocontrol agent. In this paper, we described detailed processes of strain GJ-22 colony establishment at various colonization stages. Four different types of bacterial colonies, Type 1, scattered single cells; Type 2, small cell clusters; Type 3, small cell aggregates; and Type 4, large cell aggregates, were observed in the course of bacterial colonization. We categorized bacterial colonization into four phases, which were, Phase I: bacterial colony exists as Type 1 and cell population reduced quickly; Phase II: Type 1 evolved into Type 2 and cell population remained steady; Phase III: Type 3 arose and replaced Type 2, and cell population expanded slowly; and Phase IV: Type 3 matured into Type 4 and cell population increased quickly. We have shown that the preferable location sites of bacterial aggregates on leaf phyllosphere are grooves between plant epidermal cells. Analyses of expressions of plant defence-related genes showed that, starting from Phase III, bacterial cells in the Type 3 and Type 4 colonies produced unidentified signals to induce host defence against Tobacco mosaic virus infection. In addition, we determined the crucial role of aggregates formation of GJ-22 cell on plant phyllosphere in terms of bacterial cell stress tolerance and ISR (induced systemic resistance) priming. To our knowledge, this is the first report focused on the colonization process of a phyllosphere biocontrol agent and gave a clear description on the morphological shift of bacterial colony on phyllosphere.
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Affiliation(s)
- Pin Su
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Deyong Zhang
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Zhuo Zhang
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Ang Chen
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Muhammad Rizwan Hamid
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Chenggang Li
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Jiao Du
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Ju'e Cheng
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Xinqiu Tan
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Limin Zhen
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Zhongying Zhai
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Wen Tang
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
| | - Jin Chen
- College of Bioscience and BiotechnologyHunan Agricultural UniversityChangsha410128China
| | - Xuguo Zhou
- Department of EntomologyUniversity of KentuckyLexingtonKY40546USA
| | - Yong Liu
- Hunan Plant Protection InstituteHunan Academy of Agricultural SciencesChangsha410125China
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20
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Zhang B, Zhang Y, Liang F, Ma Y, Wu X. An Extract Produced by Bacillus sp. BR3 Influences the Function of the GacS/GacA Two-Component System in Pseudomonas syringae pv. tomato DC3000. Front Microbiol 2019; 10:2005. [PMID: 31572307 PMCID: PMC6749012 DOI: 10.3389/fmicb.2019.02005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/15/2019] [Indexed: 12/03/2022] Open
Abstract
The GacS/GacA two-component system is essential for virulence in many plant pathogenic bacteria, and thus represents a promising anti-virulence target. In the present study, we isolated and screened rhizobacteria that were capable of inhibiting the expression of the gacS gene in the phytopathogenic bacterium Pseudomonas syringae pv. tomato (Pto) DC3000. One candidate inhibitor bacterium, BR3 was obtained and identified as a Bacillus sp. strain based on 16s rRNA gene sequence analysis. Besides the gacS gene, the GacA-dependent small RNA genes rsmZ and rsmY were repressed transcriptionally when DC3000 was treated with an extract from strain BR3. Importantly, the extract also influenced bacterial motility, the expression of type three secretion system effector AvrPto, and the plant hypersensitive response triggered by strain DC3000. The results suggested that the extract from strain BR3 might offer an alternative method to control bacterial diseases in plants by targeting the GacS/GacA system.
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Affiliation(s)
- Bo Zhang
- College of Agriculture, Guangxi University, Nanning, China
| | - Yang Zhang
- College of Agriculture, Guangxi University, Nanning, China
| | - Fei Liang
- College of Agriculture, Guangxi University, Nanning, China
| | - Yinan Ma
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Xiaogang Wu
- College of Agriculture, Guangxi University, Nanning, China
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21
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Xie Y, Shao X, Deng X. Regulation of type III secretion system inPseudomonas syringae. Environ Microbiol 2019; 21:4465-4477. [DOI: 10.1111/1462-2920.14779] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/10/2019] [Accepted: 08/11/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Yingpeng Xie
- Department of Biomedical SciencesCity University of Hong Kong Kowloon Tong Hong Kong SAR 999077 China
| | - Xiaolong Shao
- Department of Biomedical SciencesCity University of Hong Kong Kowloon Tong Hong Kong SAR 999077 China
| | - Xin Deng
- Department of Biomedical SciencesCity University of Hong Kong Kowloon Tong Hong Kong SAR 999077 China
- Shenzhen Research InstituteCity University of Hong Kong Shenzhen 518057 China
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22
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Quorum-dependent expression of rsmX and rsmY, small non-coding RNAs, in Pseudomonas syringae. Microbiol Res 2019; 223-225:72-78. [DOI: 10.1016/j.micres.2019.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/19/2019] [Accepted: 04/11/2019] [Indexed: 01/01/2023]
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Pseudomonas savastanoi Two-Component System RhpRS Switches between Virulence and Metabolism by Tuning Phosphorylation State and Sensing Nutritional Conditions. mBio 2019; 10:mBio.02838-18. [PMID: 30890603 PMCID: PMC6426608 DOI: 10.1128/mbio.02838-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas savastanoi uses a type III secretion system (T3SS) to invade host plants. Our previous studies have demonstrated that a two-component system (TCS), RhpRS, enables P. savastanoi to coordinate the T3SS gene expression, which depends on the phosphorylation state of RhpR under different environmental conditions. Orthologues of RhpRS are distributed in a wide range of bacterial species, indicating a general regulatory mechanism. How RhpRS uses external signals and the phosphorylation state to exercise its regulatory functions remains unknown. We performed chromatin immunoprecipitation sequencing (ChIP-seq) assays to identify the specific binding sites of RhpR and RhpRD70A in either King's B medium (KB [a T3SS-inhibiting medium]) or minimal medium (MM [a T3SS-inducing medium]). We identified 125 KB-dependent binding sites and 188 phosphorylation-dependent binding sites of RhpR. In KB, RhpR directly and positively regulated cytochrome c 550 production (via ccmA) and alcohol dehydrogenase activity (via adhB) but negatively regulated anthranilate synthase activity (via trpG) and protease activity (via hemB). In addition, phosphorylated RhpR (RhpR-P) directly and negatively regulated the T3SS (via hrpR and hopR1), swimming motility (via flhA), c-di-GMP levels (via PSPPH_2590), and biofilm formation (via algD). It positively regulated twitching motility (via fimA) and lipopolysaccharide production (via PSPPH_2653). Our transcriptome sequencing (RNA-seq) analyses identified 474 and 840 new genes that were regulated by RhpR in KB and MM, respectively. We showed nutrient-rich conditions allowed RhpR to directly regulate multiple metabolic pathways of P. savastanoi and phosphorylation enabled RhpR to specifically control virulence and the cell envelope. The action of RhpRS switched between virulence and regulation of multiple metabolic pathways by tuning its phosphorylation and sensing environmental signals in KB, respectively.IMPORTANCE The plant pathogen Pseudomonas savastanoi invades host plants through a type III secretion system, which is strictly regulated by a two-component system called RhpRS. The orthologues of RhpRS are widely distributed in the bacterial kingdom. The master regulator RhpR specifically depends on the phosphorylation state to regulate the majority of the virulence-related genes. Under nutrient-rich conditions, it modulates many important metabolic pathways, which consist of one-fifth of the genome. We propose that RhpRS uses phosphorylation- and nutrition-dependent mechanisms to switch between regulating virulence and metabolism, and this functionality is widely conserved among bacterial species.
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Wang J, Shao X, Zhang Y, Zhu Y, Yang P, Yuan J, Wang T, Yin C, Wang W, Chen S, Liang H, Deng X. HrpS Is a Global Regulator on Type III Secretion System (T3SS) and Non-T3SS Genes in Pseudomonas savastanoi pv. phaseolicola. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:1232-1243. [PMID: 29717915 DOI: 10.1094/mpmi-02-18-0035-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The type III secretion system (T3SS) is the main machinery for Pseudomonas savastanoi and other gram-negative bacteria to invade plant cells. HrpR and HrpS form a hetero-hexamer, which activates the expression of HrpL, which induces all T3SS genes by binding to a 'hrp box' in promoters. However, the individual molecular mechanism of HrpR or HrpS has not been fully understood. Through chromatin immunoprecipitation coupled to high-throughput DNA sequencing, we found that HrpR, HrpS, and HrpL had four, 47, and 31 targets on the genome, respectively. HrpS directly bound to the promoter regions of a group of T3SS genes and non-T3SS genes. HrpS independently regulated these genes in a hrpL deletion strain. Additionally, a HrpS-binding motif (GTGCCAAA) was identified, which was verified by electrophoretic mobility shift assay and lux-reporter assay. HrpS also regulated motility and biofilm formation in P. savastanoi. The present study strongly suggests that HrpS alone can work as a global regulator on both T3SS and non-T3SS genes in P. savastanoi. [Formula: see text] Copyright © 2018 The Author(s). This is an open-access article distributed under the CC BY-NC-ND 4.0 International license .
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Affiliation(s)
- Jingru Wang
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Xiaolong Shao
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Yingchao Zhang
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Yanan Zhu
- 2 Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, U.S.A
| | - Pan Yang
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Jian Yuan
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Tingting Wang
- 3 Department of Biomedical Sciences, City University of Hong Kong, 83 Tat Chee Rd, Kowloon Tong, Hong Kong
| | - Chunyan Yin
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Wei Wang
- 1 Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, Tianjin, 300457, China
| | - Sheng Chen
- 4 Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; and
| | - Haihua Liang
- 5 Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi'an, ShaanXi 710069, China
| | - Xin Deng
- 3 Department of Biomedical Sciences, City University of Hong Kong, 83 Tat Chee Rd, Kowloon Tong, Hong Kong
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Javvadi SG, Cescutti P, Rizzo R, Lonzarich V, Navarini L, Licastro D, Guarnaccia C, Venturi V. The spent culture supernatant of Pseudomonas syringae contains azelaic acid. BMC Microbiol 2018; 18:199. [PMID: 30486794 PMCID: PMC6264629 DOI: 10.1186/s12866-018-1352-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 11/20/2018] [Indexed: 11/12/2022] Open
Abstract
Background Pseudomonas syringae pv. actinidiae (PSA) is an emerging kiwifruit bacterial pathogen which since 2008 has caused considerable losses. No quorum sensing (QS) signaling molecule has yet been reported from PSA and the aim of this study was to identify possible intercellular signals produced by PSA. Results A secreted metabolome analysis resulted in the identification of 83 putative compounds, one of them was the nine carbon saturated dicarboxylic acid called azelaic acid. Azelaic acid, which is a nine-carbon (C9) saturated dicarboxylic acid, has been reported in plants as a mobile signal that primes systemic defenses. In addition, its structure,(which is associated with fatty acid biosynthesis) is similar to other known bacterial QS signals like the Diffusible Signal Facor (DSF). For these reason it could be acting as s signal molecule. Analytical and structural studies by NMR spectroscopy confirmed that in PSA spent supernatants azelaic acid was present. Quantification studies further revealed that 20 μg/L of were present and was also found in the spent supernatants of several other P. syringae pathovars. The RNAseq transcriptome study however did not determine whether azelaic acid could behave as a QS molecule. Conclusions This study reports of the possible natural biosynthesis of azelaic acid by bacteria. The production of azelaic acid by P. syringae pathovars can be associated with plant-bacteria signaling. Electronic supplementary material The online version of this article (10.1186/s12866-018-1352-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Paola Cescutti
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Roberto Rizzo
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | | | | | | | - Corrado Guarnaccia
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
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Li L, Yuan L, Shi Y, Xie X, Chai A, Wang Q, Li B. Comparative genomic analysis of Pseudomonas amygdali pv. lachrymans NM002: Insights into its potential virulence genes and putative invasion determinants. Genomics 2018; 111:1493-1503. [PMID: 30336277 DOI: 10.1016/j.ygeno.2018.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/30/2018] [Accepted: 10/04/2018] [Indexed: 12/01/2022]
Abstract
Pseudomonas amygdali pv. lachrymans is currently of important plant pathogenic bacteria that causes cucumber angular leaf spot worldwide. The pathogen has been studied for its roles in pathogenicity and plant inheritance resistance. To further delineate traits critical to virulence, invasion and survival in the phyllosphere, we reported the first complete genome of P. amygdali pv. lachrymans NM002. Analysis of the whole genome in comparison with three closely-related representative pathovars of P. syringae identified the conservation of virulence genes, including flagella and chemotaxis, quorum-sensing systems, two-component systems, and lipopolysaccharide and antiphagocytosis. It also revealed differences of invasion determinants, such as type III effectors, phytotoxin (coronatine, syringomycin and phaseolotoxin) and cell wall-degrading enzyme, which may contribute to infectivity. The aim of this study was to derive genomic information that would reveal the probable molecular mechanisms underlying the virulence, infectivity and provide a better understanding of the pathogenesis of the P. syringae pathovars.
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Affiliation(s)
- Lei Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Lifang Yuan
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Yanxia Shi
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xuewen Xie
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Ali Chai
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Qi Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Baoju Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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Quorum Sensing in Pseudomonas savastanoi pv. savastanoi and Erwinia toletana: Role in Virulence and Interspecies Interactions in the Olive Knot. Appl Environ Microbiol 2018; 84:AEM.00950-18. [PMID: 30006401 DOI: 10.1128/aem.00950-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/06/2018] [Indexed: 12/13/2022] Open
Abstract
The olive knot disease (Olea europea L.) is caused by the bacterium Pseudomonas savastanoi pv. savastanoi. P. savastanoi pv. savastanoi in the olive knot undergoes interspecies interactions with the harmless endophyte Erwinia toletana; P. savastanoi pv. savastanoi and E. toletana colocalize and form a stable community, resulting in a more aggressive disease. P. savastanoi pv. savastanoi and Etoletana produce the same type of the N-acylhomoserine lactone (AHL) quorum sensing (QS) signal, and they share AHLs in planta In this work, we have further studied the AHL QS systems of P. savastanoi pv. savastanoi and Etoletana in order to determine possible molecular mechanism(s) involved in this bacterial interspecies interaction/cooperation. The AHL QS regulons of P. savastanoi pv. savastanoi and Etoletana were determined, allowing the identification of several QS-regulated genes. Surprisingly, the P. savastanoi pv. savastanoi QS regulon consisted of only a few loci whereas in Etoletana many putative metabolic genes were regulated by QS, among which are several involved in carbohydrate metabolism. One of these loci was the aldolase-encoding gene garL, which was found to be essential for both colocalization of P. savastanoi pv. savastanoi and Etoletana cells inside olive knots as well as knot development. This study further highlighted that pathogens can cooperate with commensal members of the plant microbiome.IMPORTANCE This is a report on studies of the quorum sensing (QS) systems of the olive knot pathogen Pseudomonas savastanoi pv. savastanoi and olive knot cooperator Erwinia toletana These two bacterial species form a stable community in the olive knot, share QS signals, and cooperate, resulting in a more aggressive disease. In this work we further studied the QS systems by determining their regulons as well as by studying QS-regulated genes which might play a role in this cooperation. This represents a unique in vivo interspecies bacterial virulence model and highlights the importance of bacterial interspecies interaction in disease.
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Yan L, Tang Q, Guan Z, Pei K, Zou T, He J. Structural insights into operator recognition by BioQ in the Mycobacterium smegmatis biotin synthesis pathway. Biochim Biophys Acta Gen Subj 2018; 1862:1843-1851. [PMID: 29852200 DOI: 10.1016/j.bbagen.2018.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 04/18/2018] [Accepted: 05/19/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Biotin is an essential cofactor in living organisms. The TetR family transcriptional regulator (TFTR) BioQ is the main regulator of biotin synthesis in Mycobacterium smegmatis. BioQ represses the expression of its target genes by binding to a conserved palindromic DNA sequence (the BioQ operator). However, the mechanism by which BioQ recognizes this DNA element has not yet been fully elucidated. METHODS/RESULTS We solved the crystal structures of the BioQ homodimer in its apo-form and in complex with its specific operator at 2.26 Å and 2.69 Å resolution, respectively. BioQ inserts the N-terminal recognition helix of each protomer into the corresponding major grooves of its operator and stabilizes the formation of the complex via electrostatic interactions and hydrogen bonding to induce conformational changes in both the DNA and BioQ. The DNA interface of BioQ is rich in positively charged residues, which help BioQ stabilize DNA binding. We elucidated the structural basis of DNA recognition by BioQ for the first time and identified the amino acid residues responsible for DNA binding via further site-directed mutagenesis. GENERAL SIGNIFICANCE Our findings clearly elucidate the mechanism by which BioQ recognizes its operator in the biotin synthesis pathway and reveal the unique structural characteristics of BioQ that are distinct from other TFTR members.
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Affiliation(s)
- Ling Yan
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Qing Tang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Zeyuan Guan
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Kai Pei
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Tingting Zou
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
| | - Jin He
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
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Chagas FO, Pessotti RDC, Caraballo-Rodríguez AM, Pupo MT. Chemical signaling involved in plant-microbe interactions. Chem Soc Rev 2018; 47:1652-1704. [PMID: 29218336 DOI: 10.1039/c7cs00343a] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microorganisms are found everywhere, and they are closely associated with plants. Because the establishment of any plant-microbe association involves chemical communication, understanding crosstalk processes is fundamental to defining the type of relationship. Although several metabolites from plants and microbes have been fully characterized, their roles in the chemical interplay between these partners are not well understood in most cases, and they require further investigation. In this review, we describe different plant-microbe associations from colonization to microbial establishment processes in plants along with future prospects, including agricultural benefits.
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Affiliation(s)
- Fernanda Oliveira Chagas
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (FCFRP-USP), Avenida do Café, s/n, 14040-903, Ribeirão Preto-SP, Brazil.
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Sawada T, Eguchi M, Asaki S, Kashiwagi R, Shimomura K, Taguchi F, Matsui H, Yamamoto M, Noutoshi Y, Toyoda K, Ichinose Y. MexEF-OprN multidrug efflux pump transporter negatively controls N-acyl-homoserine lactone accumulation in pseudomonas syringae pv. Tabaci 6605. Mol Genet Genomics 2018; 293:907-917. [PMID: 29549432 DOI: 10.1007/s00438-018-1430-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 03/09/2018] [Indexed: 01/28/2023]
Abstract
Our previous studies revealed that flagellar-motility-defective mutants such as ∆fliC of Pseudomonas syringae pv. tabaci 6605 (Pta6605) have remarkably reduced production of N-acyl-homoserine lactones (AHL), quorum-sensing molecules. To investigate the reason of loss of AHL production in ∆fliC mutant, we carried out transposon mutagenesis. Among approximately 14,000 transconjugants, we found 11 AHL production-recovered (APR) strains. In these APR strains, a transposon was inserted into either mexE or mexF, genes encoding for the multidrug efflux pump transporter MexEF-OprN, and mexT, a gene encoding a putative transcriptional activator for mexEF-oprN. These results suggest that MexEF-OprN is a negative regulator of AHL production. To confirm the negative effect of MexEF-OprN on AHL production, loss- and gain-of-function experiments for mexEF-oprN were carried out. The ∆fliC∆mexF and ∆fliC∆mexT double mutant strains recovered AHL production, whereas the mexT overexpressing strain abolished AHL production, although the psyI, a gene encoding AHL synthase, is transcribed as wild type. Introduction of a mexF or mexT mutation into another flagellar-motility- and AHL production-defective mutant strain, ∆motCD, also recovered the ability to produce AHL. Furthermore, introduction of the mexF mutation into other AHL production-defective mutant strains such as ∆gacA and ∆aefR also recovered AHL production but not to the ∆psyI mutant. These results indicate that MexEF-OprN is a decisive negative determinant of AHL production and accumulation.
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Affiliation(s)
- Takahiro Sawada
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Miho Eguchi
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Seiya Asaki
- Faculty of Agriculture, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Ryota Kashiwagi
- Faculty of Agriculture, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Kousuke Shimomura
- Faculty of Agriculture, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Fumiko Taguchi
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - Hidenori Matsui
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Mikihiro Yamamoto
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Yoshiteru Noutoshi
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Kazuhiro Toyoda
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Yuki Ichinose
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan.
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Cheng F, Ma A, Zhuang G, Fray RG. Exogenous N-acyl-homoserine lactones enhance the expression of flagella of Pseudomonas syringae and activate defence responses in plants. MOLECULAR PLANT PATHOLOGY 2018; 19:104-115. [PMID: 27756102 PMCID: PMC6637982 DOI: 10.1111/mpp.12502] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 10/11/2016] [Accepted: 10/17/2016] [Indexed: 05/05/2023]
Abstract
In order to cope with pathogens, plants have evolved sophisticated mechanisms to sense pathogenic attacks and to induce defence responses. The N-acyl-homoserine lactone (AHL)-mediated quorum sensing in bacteria regulates diverse physiological processes, including those involved in pathogenicity. In this work, we study the interactions between AHL-producing transgenic tobacco plants and Pseudomonas syringae pv. tabaci 11528 (P. syringae 11528). Both a reduced incidence of disease and decrease in the growth of P. syringae 11528 were observed in AHL-producing plants compared with wild-type plants. The present data indicate that plant-produced AHLs enhance disease resistance against this pathogen. Subsequent RNA-sequencing analysis showed that the exogenous addition of AHLs up-regulated the expression of P. syringae 11528 genes for flagella production. Expression levels of plant defence genes in AHL-producing and wild-type plants were determined by quantitative real-time polymerase chain reaction. These data showed that plant-produced AHLs activated a wide spectrum of defence responses in plants following inoculation, including the oxidative burst, hypersensitive response, cell wall strengthening, and the production of certain metabolites. These results demonstrate that exogenous AHLs alter the gene expression patterns of pathogens, and plant-produced AHLs either directly or indirectly enhance plant local immunity during the early stage of plant infection.
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Affiliation(s)
- Feifei Cheng
- Research Center for Eco‐Environment SciencesChinese Academy of SciencesBeijing100085China
- University of the Chinese Academy of SciencesBeijing100049China
| | - Anzhou Ma
- Research Center for Eco‐Environment SciencesChinese Academy of SciencesBeijing100085China
- University of the Chinese Academy of SciencesBeijing100049China
| | - Guoqiang Zhuang
- Research Center for Eco‐Environment SciencesChinese Academy of SciencesBeijing100085China
- University of the Chinese Academy of SciencesBeijing100049China
| | - Rupert G. Fray
- School of Biological SciencesNottingham UniversityLoughboroughLE12 5RDUK
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Leguina ACDV, Nieto C, Pajot HF, Bertini EV, Mac Cormack W, Castellanos de Figueroa LI, Nieto-Peñalver CG. Inactivation of bacterial quorum sensing signals N-acyl homoserine lactones is widespread in yeasts. Fungal Biol 2018; 122:52-62. [DOI: 10.1016/j.funbio.2017.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 09/04/2017] [Accepted: 10/15/2017] [Indexed: 11/16/2022]
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Kim SR, Yeon KM. Quorum Sensing as Language of Chemical Signals. FUNDAMENTALS OF QUORUM SENSING, ANALYTICAL METHODS AND APPLICATIONS IN MEMBRANE BIOREACTORS 2018. [DOI: 10.1016/bs.coac.2018.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Pseudomonas syringae pv. syringae B728a Regulates Multiple Stages of Plant Colonization via the Bacteriophytochrome BphP1. mBio 2017; 8:mBio.01178-17. [PMID: 29066541 PMCID: PMC5654926 DOI: 10.1128/mbio.01178-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Light may be an important environmental signal for plant-associated bacteria, particularly those that live on leaves. An integrated network of red/far-red- and blue-light-responsive photosensory proteins is known to inhibit swarming motility in the foliar plant pathogen Pseudomonas syringae pv. syringae B728a. Here we elucidated factors in the red/far-red-light-sensing bacteriophytochrome BphP1 signal transduction pathway and report evidence for a role of BphP1 in multiple stages of the P. syringae B728a life cycle. We report that BphP1 signaling involves the downstream regulator Bsi (bacteriophytochrome-regulated swarming inhibitor) and an acyl-homoserine lactone (AHL) signal. Loss of bphP1 or bsi resulted in the early initiation of swarm tendrils during swarming motility, a phenotype that was dependent on red/far-red light and reversed by exogenous AHL, illustrating that the BphP1-Bsi-AHL pathway inhibits the transition from a sessile state to a motile state. Loss of bphP1 or bsi resulted in larger water-soaked lesions induced on bean (Phaseolus vulgaris) pods and enhanced movement from soil and buried plant tissues to seeds, demonstrating that BphP1 and Bsi negatively regulate virulence and bacterial movement through soil to seeds. Moreover, BphP1, but not Bsi, contributed to leaf colonization; loss of bphP1 reduced survival on leaves immediately following inoculation but enhanced the size of the subsequently established populations. Neither Bsi nor Smp, a swarm motility-promoting regulator identified here, affected leaf colonization, indicating that BphP1-mediated contributions to leaf colonization are, at least in part, independent of swarming motility. These results demonstrate that P. syringae B728a red-light sensing involves a multicomponent, branched regulatory pathway that affects several stages of its life cycle. Microbes on plants are particularly well positioned to exploit light cues based on the importance of light to plant growth. Photosensory proteins enable organisms to sense light and respond to light, but their roles in the life cycles of plant microbes are poorly understood. This study investigated the cellular components and ecological roles of red/far-red-light sensing in the foliar bacterial pathogen Pseudomonas syringae. The study demonstrated that a bacteriophytochrome photosensory protein functions via a multicomponent, branched regulatory pathway that operates primarily through red/far-red-light-mediated inhibition. This pathway negatively regulates the transition from sessile to motile states under conditions conducive to swarming motility. It also negatively regulates virulence on bean pods, movement through soil to seeds, and survival following inoculation on leaves, but it positively contributes to the eventual establishment of leaf-borne populations. These results provide strong evidence that light sensing modulates behaviors at multiple stages in the life cycle of a nonphotosynthetic, plant microbe.
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Cheng F, Ma A, Luo J, Zhuang X, Zhuang G. N-acylhomoserine lactone-regulation of genes mediating motility and pathogenicity in Pseudomonas syringae pathovar tabaci 11528. Microbiologyopen 2017; 6:e00440. [PMID: 28133926 PMCID: PMC5458577 DOI: 10.1002/mbo3.440] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/28/2016] [Accepted: 12/07/2016] [Indexed: 11/11/2022] Open
Abstract
Pseudomonas syringae pathovar tabaci 11528 (P. syringae 11528) is a phytopathogen that causes wild-fire disease in soybean and tobacco plants. It utilizes a cell density-dependent regulation system known as quorum sensing (QS). In its QS system, the psyI is responsible for the biosynthesis of N-acylhomoserine lactones (AHLs). By comparing the transcripts from P. syringae 11528 wild-type strain with those of the ΔpsyI mutant using RNA sequencing (RNA-seq) technology, 1118 AHL-regulated genes were identified in the transition from exponential to stationary growth phase. Numerous AHL-regulated genes involved in pathogenicity were negatively controlled, including genes linked to flagella, chemotaxis, pilus, extracellular polysaccharides, secretion systems, and two-component system. Moreover, gene ontology and pathway enrichment analysis revealed that the most pronounced regulation was associated with bacterial motility. Finally, phenotypic assays showed that QS-regulated traits were involved in epiphytic growth of pathogens and disease development in plants. These findings imply that the AHL-mediated QS system in P. syringae 11528 plays significant roles in distinct stages of interactions between plants and pathogens, including early plant colonization and late plant infection.
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Affiliation(s)
- Feifei Cheng
- Research Center for Eco‐Environment SciencesChinese Academy of SciencesBeijingChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Anzhou Ma
- Research Center for Eco‐Environment SciencesChinese Academy of SciencesBeijingChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Jinxue Luo
- Research Center for Eco‐Environment SciencesChinese Academy of SciencesBeijingChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Xuliang Zhuang
- Research Center for Eco‐Environment SciencesChinese Academy of SciencesBeijingChina
- University of the Chinese Academy of SciencesBeijingChina
| | - Guoqiang Zhuang
- Research Center for Eco‐Environment SciencesChinese Academy of SciencesBeijingChina
- University of the Chinese Academy of SciencesBeijingChina
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Three-Dimensional Numerical Simulations of Biofilm Dynamics with Quorum Sensing in a Flow Cell. Bull Math Biol 2017; 79:884-919. [PMID: 28290008 DOI: 10.1007/s11538-017-0259-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 02/15/2017] [Indexed: 10/20/2022]
Abstract
We develop a multiphasic hydrodynamic theory for biofilms taking into account interactions among various bacterial phenotypes, extracellular polymeric substance (EPS), quorum sensing (QS) molecules, solvent, and antibiotics. In the model, bacteria are classified into down-regulated QS, up-regulated QS, and non-QS cells based on their QS ability. The model is first benchmarked against an experiment yielding an excellent fit to experimental measurements on the concentration of QS molecules and the cell density during biofilm development. It is then applied to study development of heterogeneous structures in biofilms due to interactions of QS regulation, hydrodynamics, and antimicrobial treatment. Our 3D numerical simulations have confirmed that (i). QS is beneficial for biofilm development in a long run by building a robust EPS population to protect the biofilm; (ii). biofilms located upstream can induce QS downstream when the colonies are close enough spatially; (iii). QS induction may not be fully operational and can even be compromised in strong laminar flows; (v). the hydrodynamic stress alters the biofilm morphology. Through further numerical investigations, our model suggests that (i). QS-regulated EPS production contributes to the structural formation of heterogeneous biofilms; (ii) QS down-regulated cells tend to grow at the surface of the biofilm while QS up-regulated ones tend to grow in the bulk; (iii) when nutrient supply is sufficient, QS induction might be more effective upstream than downstream; (iv) QS may be of little benefit in a short timescale in term of fighting against invading strain/species; (v) the material properties of biomass (bacteria and EPS) have strong impact on the dilution of QS molecules under strong shear flow. In addition, with this modeling framework, hydrodynamic details and rheological quantities associated with biofilm formation under QS regulation can be resolved.
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Bauer JS, Hauck N, Christof L, Mehnaz S, Gust B, Gross H. The Systematic Investigation of the Quorum Sensing System of the Biocontrol Strain Pseudomonas chlororaphis subsp. aurantiaca PB-St2 Unveils aurI to Be a Biosynthetic Origin for 3-Oxo-Homoserine Lactones. PLoS One 2016; 11:e0167002. [PMID: 27861617 PMCID: PMC5115851 DOI: 10.1371/journal.pone.0167002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/07/2016] [Indexed: 11/30/2022] Open
Abstract
The shoot endophytic biocontrol strain Pseudomonas chlororaphis subsp. aurantiaca PB-St2 produces a wide range of exoproducts, including enzymes and antibiotics. The production of exoproducts is commonly tightly regulated. In order to get a deeper insight into the regulatory network of PB-St2, the strain was systematically investigated regarding its quorum sensing systems, both on the genetic and metabolic level. The genome analysis of PB-St2 revealed the presence of four putative acyl homoserine lactone (AHL) biosynthesis genes: phzI, csaI, aurI, and hdtS. LC-MS/MS analyses of the crude supernatant extracts demonstrated that PB-St2 produces eight AHLs. In addition, the concentration of all AHL derivatives was quantified time-resolved in parallel over a period of 42 h during the growth of P. aurantiaca PB-St2, resulting in production curves, which showed differences regarding the maximum levels of the AHLs (14.6 nM– 1.75 μM) and the production period. Cloning and heterologous overexpression of all identified AHL synthase genes in Escherichia coli proved the functionality of the resulting synthases PhzI, CsaI, and AurI. A clear AHL production pattern was assigned to each of these three AHL synthases, while the HdtS synthase did not lead to any AHL production. Furthermore, the heterologous expression study demonstrated unequivocally and for the first time that AurI directs the synthesis of two 3-oxo-AHLs.
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Affiliation(s)
- Judith S. Bauer
- Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tuebingen, Tuebingen, Germany
- German Centre for Infection Research (DZIF), Partner site Tuebingen, Tuebingen, Germany
| | - Nils Hauck
- Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tuebingen, Tuebingen, Germany
- German Centre for Infection Research (DZIF), Partner site Tuebingen, Tuebingen, Germany
| | - Lisa Christof
- Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tuebingen, Tuebingen, Germany
- German Centre for Infection Research (DZIF), Partner site Tuebingen, Tuebingen, Germany
| | - Samina Mehnaz
- Department of Biological Sciences, Forman Christian College (A Chartered University), Lahore, Pakistan
| | - Bertolt Gust
- Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tuebingen, Tuebingen, Germany
- German Centre for Infection Research (DZIF), Partner site Tuebingen, Tuebingen, Germany
| | - Harald Gross
- Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tuebingen, Tuebingen, Germany
- German Centre for Infection Research (DZIF), Partner site Tuebingen, Tuebingen, Germany
- * E-mail:
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Pfeilmeier S, Caly DL, Malone JG. Bacterial pathogenesis of plants: future challenges from a microbial perspective: Challenges in Bacterial Molecular Plant Pathology. MOLECULAR PLANT PATHOLOGY 2016; 17:1298-313. [PMID: 27170435 PMCID: PMC6638335 DOI: 10.1111/mpp.12427] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/08/2016] [Accepted: 05/10/2016] [Indexed: 05/03/2023]
Abstract
Plant infection is a complicated process. On encountering a plant, pathogenic microorganisms must first adapt to life on the epiphytic surface, and survive long enough to initiate an infection. Responsiveness to the environment is critical throughout infection, with intracellular and community-level signal transduction pathways integrating environmental signals and triggering appropriate responses in the bacterial population. Ultimately, phytopathogens must migrate from the epiphytic surface into the plant tissue using motility and chemotaxis pathways. This migration is coupled with overcoming the physical and chemical barriers to entry into the plant apoplast. Once inside the plant, bacteria use an array of secretion systems to release phytotoxins and protein effectors that fulfil diverse pathogenic functions (Fig. ) (Melotto and Kunkel, ; Phan Tran et al., ). As our understanding of the pathways and mechanisms underpinning plant pathogenicity increases, a number of central research challenges are emerging that will profoundly shape the direction of research in the future. We need to understand the bacterial phenotypes that promote epiphytic survival and surface adaptation in pathogenic bacteria. How do these pathways function in the context of the plant-associated microbiome, and what impact does this complex microbial community have on the onset and severity of plant infections? The huge importance of bacterial signal transduction to every stage of plant infection is becoming increasingly clear. However, there is a great deal to learn about how these signalling pathways function in phytopathogenic bacteria, and the contribution they make to various aspects of plant pathogenicity. We are increasingly able to explore the structural and functional diversity of small-molecule natural products from plant pathogens. We need to acquire a much better understanding of the production, deployment, functional redundancy and physiological roles of these molecules. Type III secretion systems (T3SSs) are important and well-studied contributors to bacterial disease. Several key unanswered questions will shape future investigations of these systems. We need to define the mechanism of hierarchical and temporal control of effector secretion. For successful infection, effectors need to interact with host components to exert their function. Advanced biochemical, proteomic and cell biological techniques will enable us to study the function of effectors inside the host cell in more detail and on a broader scale. Population genomics analyses provide insight into evolutionary adaptation processes of phytopathogens. The determination of the diversity and distribution of type III effectors (T3Es) and other virulence genes within and across pathogenic species, pathovars and strains will allow us to understand how pathogens adapt to specific hosts, the evolutionary pathways available to them, and the possible future directions of the evolutionary arms race between effectors and molecular plant targets. Although pathogenic bacteria employ a host of different virulence and proliferation strategies, as a result of the space constraints, this review focuses mainly on the hemibiotrophic pathogens. We discuss the process of plant infection from the perspective of these important phytopathogens, and highlight new approaches to address the outstanding challenges in this important and fast-moving field.
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Affiliation(s)
- Sebastian Pfeilmeier
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Delphine L Caly
- Université de Lille, EA 7394, ICV - Institut Charles Viollette, Lille, F-59000, France
| | - Jacob G Malone
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
- University of East Anglia, Norwich, NR4 7TJ, UK.
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Scott RA, Lindow SE. Transcriptional control of quorum sensing and associated metabolic interactions inPseudomonas syringaestrain B728a. Mol Microbiol 2016; 99:1080-98. [DOI: 10.1111/mmi.13289] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/02/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Russell A. Scott
- Department of Plant and Microbial Biology; University of California; 111 Koshland Hall Berkeley CA 94720-3102 USA
| | - Steven E. Lindow
- Department of Plant and Microbial Biology; University of California; 111 Koshland Hall Berkeley CA 94720-3102 USA
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40
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Mensi I, Daugrois JH, Pieretti I, Gargani D, Fleites LA, Noell J, Bonnot F, Gabriel DW, Rott P. Surface polysaccharides and quorum sensing are involved in the attachment and survival of Xanthomonas albilineans on sugarcane leaves. MOLECULAR PLANT PATHOLOGY 2016; 17:236-246. [PMID: 25962850 PMCID: PMC6638434 DOI: 10.1111/mpp.12276] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Xanthomonas albilineans, the causal agent of sugarcane leaf scald, is a bacterial plant pathogen that is mainly spread by infected cuttings and contaminated harvesting tools. However, some strains of this pathogen are known to be spread by aerial means and are able to colonize the phyllosphere of sugarcane before entering the host plant and causing disease. The objective of this study was to identify the molecular factors involved in the survival or growth of X. albilineans on sugarcane leaves. We developed a bioassay to test for the attachment of X. albilineans on sugarcane leaves using tissue-cultured plantlets grown in vitro. Six mutants of strain XaFL07-1 affected in surface polysaccharide production completely lost their capacity to survive on the sugarcane leaf surface. These mutants produced more biofilm in vitro and accumulated more cellular poly-β-hydroxybutyrate than the wild-type strain. A mutant affected in the production of small molecules (including potential biosurfactants) synthesized by non-ribosomal peptide synthetases (NRPSs) attached to the sugarcane leaves as well as the wild-type strain. Surprisingly, the attachment of bacteria on sugarcane leaves varied among mutants of the rpf gene cluster involved in bacterial quorum sensing. Therefore, quorum sensing may affect polysaccharide production, or both polysaccharides and quorum sensing may be involved in the survival or growth of X. albilineans on sugarcane leaves.
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Affiliation(s)
- Imene Mensi
- UMR BGPI, CIRAD, F-34398, Montpellier, France
| | | | | | | | - Laura A Fleites
- Plant Pathology Department, University of Florida, Gainesville, 32611, USA
| | - Julie Noell
- UMR BGPI, CIRAD, F-34398, Montpellier, France
| | | | - Dean W Gabriel
- Plant Pathology Department, University of Florida, Gainesville, 32611, USA
| | - Philippe Rott
- UMR BGPI, CIRAD, F-34398, Montpellier, France
- Plant Pathology Department, University of Florida, Gainesville, 32611, USA
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41
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Yun S, Lee JS, Do MS, Jeon YJ, Cha JY, Baik HS. Functional analysis of the aefR mutation and identification of its binding site in Pseudomonas syringae pv. tabaci 11528. Acta Biochim Biophys Sin (Shanghai) 2015; 47:938-45. [PMID: 26376742 DOI: 10.1093/abbs/gmv091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/20/2015] [Indexed: 11/14/2022] Open
Abstract
The TetR family transcriptional regulator AefR contributes to the regulation of the quorum-sensing system. However, the role of AefR in the regulatory network of the phytopathogen Pseudomonas syringae pathovars is not known. In this study, the phenotype of a P. syringae pv. tabaci 11528 aefR deletion mutant strain was examined. The aefR gene expression and AefR DNA-binding affinity were examined by quantitative real-time polymerase chain reaction and electrophoretic mobility shift assay, respectively. AefR was found to control quorum-sensing genes as well as the efflux genes mexE, mexF, and oprN via an indirect mechanism. AefR binds to its own operator site as well as to the palindromic sequence between positions -28 and -2 corresponding to the transcription start site of aefR, as determined by dye primer sequencing. These results suggest that P. syringae AefR modulates quorum sensing and efflux as well as its own expression, which can be exploited by strategies developed to manage this plant parasite.
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Affiliation(s)
- Sora Yun
- Department of Integrated Biological Science, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
| | - Jun Seung Lee
- Department of Integrated Biological Science, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
| | - Mi Sol Do
- Department of Integrated Biological Science, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
| | - Young Ji Jeon
- Department of Integrated Biological Science, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
| | - Ji Young Cha
- Department of Biotechnology and Bioengineering, College of Engineering, Dong-Eui University, Busan 614-714, Republic of Korea
| | - Hyung Suk Baik
- Department of Integrated Biological Science, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
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42
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Kakkar A, Nizampatnam NR, Kondreddy A, Pradhan BB, Chatterjee S. Xanthomonas campestris cell-cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6697-714. [PMID: 26248667 PMCID: PMC4623683 DOI: 10.1093/jxb/erv377] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell-cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell-cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery.
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Affiliation(s)
- Akanksha Kakkar
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India Graduate studies, Manipal University, Manipal, India
| | | | - Anil Kondreddy
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
| | - Binod Bihari Pradhan
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
| | - Subhadeep Chatterjee
- Centre for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad 500001, India
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43
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Kresovic D, Schempp F, Cheikh-Ali Z, Bode HB. A novel and widespread class of ketosynthase is responsible for the head-to-head condensation of two acyl moieties in bacterial pyrone biosynthesis. Beilstein J Org Chem 2015; 11:1412-7. [PMID: 26425196 PMCID: PMC4578411 DOI: 10.3762/bjoc.11.152] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/22/2015] [Indexed: 01/22/2023] Open
Abstract
The biosynthesis of photopyrones, novel quorum sensing signals in Photorhabdus, has been studied by heterologous expression of the photopyrone synthase PpyS catalyzing the head-to-head condensation of two acyl moieties. The biochemical mechanism of pyrone formation has been investigated by amino acid exchange and bioinformatic analysis. Additionally, the evolutionary origin of PpyS has been studied by phylogenetic analyses also revealing homologous enzymes in Pseudomonas sp. GM30 responsible for the biosynthesis of pseudopyronines including a novel derivative. Moreover this novel class of ketosynthases is only distantly related to other pyrone-forming enzymes identified in the biosynthesis of the potent antibiotics myxopyronin and corallopyronin.
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Affiliation(s)
- Darko Kresovic
- Merck Stiftungsprofessur für Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438 Frankfurt am Main, Germany
| | - Florence Schempp
- Merck Stiftungsprofessur für Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438 Frankfurt am Main, Germany
| | - Zakaria Cheikh-Ali
- Merck Stiftungsprofessur für Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438 Frankfurt am Main, Germany
| | - Helge B Bode
- Merck Stiftungsprofessur für Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438 Frankfurt am Main, Germany ; Buchmann Institute for Molecular Life Sciences (BMLS), Goethe Universität Frankfurt, 60438 Frankfurt am Main, Germany
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44
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Trantas EA, Licciardello G, Almeida NF, Witek K, Strano CP, Duxbury Z, Ververidis F, Goumas DE, Jones JDG, Guttman DS, Catara V, Sarris PF. Comparative genomic analysis of multiple strains of two unusual plant pathogens: Pseudomonas corrugata and Pseudomonas mediterranea. Front Microbiol 2015; 6:811. [PMID: 26300874 PMCID: PMC4528175 DOI: 10.3389/fmicb.2015.00811] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/22/2015] [Indexed: 11/13/2022] Open
Abstract
The non-fluorescent pseudomonads, Pseudomonas corrugata (Pcor) and P. mediterranea (Pmed), are closely related species that cause pith necrosis, a disease of tomato that causes severe crop losses. However, they also show strong antagonistic effects against economically important pathogens, demonstrating their potential for utilization as biological control agents. In addition, their metabolic versatility makes them attractive for the production of commercial biomolecules and bioremediation. An extensive comparative genomics study is required to dissect the mechanisms that Pcor and Pmed employ to cause disease, prevent disease caused by other pathogens, and to mine their genomes for genes that encode proteins involved in commercially important chemical pathways. Here, we present the draft genomes of nine Pcor and Pmed strains from different geographical locations. This analysis covered significant genetic heterogeneity and allowed in-depth genomic comparison. All examined strains were able to trigger symptoms in tomato plants but not all induced a hypersensitive-like response in Nicotiana benthamiana. Genome-mining revealed the absence of type III secretion system and known type III effector-encoding genes from all examined Pcor and Pmed strains. The lack of a type III secretion system appears to be unique among the plant pathogenic pseudomonads. Several gene clusters coding for type VI secretion system were detected in all genomes. Genome-mining also revealed the presence of gene clusters for biosynthesis of siderophores, polyketides, non-ribosomal peptides, and hydrogen cyanide. A highly conserved quorum sensing system was detected in all strains, although species specific differences were observed. Our study provides the basis for in-depth investigations regarding the molecular mechanisms underlying virulence strategies in the battle between plants and microbes.
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Affiliation(s)
- Emmanouil A Trantas
- Plant Biochemistry and Biotechnology Laboratory, Department of Agriculture, School of Agriculture and Food Technology, Technological Educational Institute of Crete Heraklion, Greece
| | | | - Nalvo F Almeida
- School of Computing, Federal University of Mato Grosso do Sul Campo Grande, Brazil
| | - Kamil Witek
- The Sainsbury Laboratory, John Innes Centre Norwich, UK
| | - Cinzia P Strano
- Department of Agriculture, Food and Environment, University of Catania Catania, Italy
| | - Zane Duxbury
- The Sainsbury Laboratory, John Innes Centre Norwich, UK
| | - Filippos Ververidis
- Plant Biochemistry and Biotechnology Laboratory, Department of Agriculture, School of Agriculture and Food Technology, Technological Educational Institute of Crete Heraklion, Greece
| | - Dimitrios E Goumas
- Plant Biochemistry and Biotechnology Laboratory, Department of Agriculture, School of Agriculture and Food Technology, Technological Educational Institute of Crete Heraklion, Greece ; Plant Pathology and Bacteriology Laboratory, Department of Agriculture, School of Agriculture and Food Technology, Technological Educational Institute of Crete Heraklion, Greece
| | | | - David S Guttman
- Centre for the Analysis of Genome Evolution & Function, University of Toronto Toronto, ON, Canada
| | - Vittoria Catara
- Department of Agriculture, Food and Environment, University of Catania Catania, Italy
| | - Panagiotis F Sarris
- Plant Biochemistry and Biotechnology Laboratory, Department of Agriculture, School of Agriculture and Food Technology, Technological Educational Institute of Crete Heraklion, Greece ; The Sainsbury Laboratory, John Innes Centre Norwich, UK
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45
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Ravindran A, Jalan N, Yuan JS, Wang N, Gross DC. Comparative genomics of Pseudomonas syringae pv. syringae strains B301D and HS191 and insights into intrapathovar traits associated with plant pathogenesis. Microbiologyopen 2015; 4:553-73. [PMID: 25940918 PMCID: PMC4554452 DOI: 10.1002/mbo3.261] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 03/17/2015] [Accepted: 03/27/2015] [Indexed: 01/09/2023] Open
Abstract
Pseudomonas syringae pv. syringae is a common plant-associated bacterium that causes diseases of both monocot and dicot plants worldwide. To help delineate traits critical to adaptation and survival in the plant environment, we generated complete genome sequences of P. syringae pv. syringae strains B301D and HS191, which represent dicot and monocot strains with distinct host specificities. Intrapathovar comparisons of the B301D (6.09 Mb) and HS191 (5.95 Mb plus a 52 kb pCG131 plasmid) genomes to the previously sequenced B728a genome demonstrated that the shared genes encompass about 83% of each genome, and include genes for siderophore biosynthesis, osmotolerance, and extracellular polysaccharide production. Between 7% and 12% of the genes are unique among the genomes, and most of the unique gene regions carry transposons, phage elements, or IS elements associated with horizontal gene transfer. Differences are observed in the type III effector composition for the three strains that likely influences host range. The HS191 genome had the largest number at 25 of effector genes, and seven effector genes are specific to this monocot strain. Toxin production is another major trait associated with virulence of P. syringae pv. syringae, and HS191 is distinguished by genes for production of syringopeptin SP25 and mangotoxin.
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Affiliation(s)
- Aravind Ravindran
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas, 77843-2132
| | - Neha Jalan
- Department of Microbiology and Cell Sciences, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida, 33850
| | - Joshua S Yuan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas, 77843-2132
| | - Nian Wang
- Department of Microbiology and Cell Sciences, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida, 33850
| | - Dennis C Gross
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas, 77843-2132
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Helman Y, Chernin L. Silencing the mob: disrupting quorum sensing as a means to fight plant disease. MOLECULAR PLANT PATHOLOGY 2015; 16:316-29. [PMID: 25113857 PMCID: PMC6638422 DOI: 10.1111/mpp.12180] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Bacteria are able to sense their population's density through a cell-cell communication system, termed 'quorum sensing' (QS). This system regulates gene expression in response to cell density through the constant production and detection of signalling molecules. These molecules commonly act as auto-inducers through the up-regulation of their own synthesis. Many pathogenic bacteria, including those of plants, rely on this communication system for infection of their hosts. The finding that the countering of QS-disrupting mechanisms exists in many prokaryotic and eukaryotic organisms offers a promising novel method to fight disease. During the last decade, several approaches have been proposed to disrupt QS pathways of phytopathogens, and hence to reduce their virulence. Such studies have had varied success in vivo, but most lend promising support to the idea that QS manipulation could be a potentially effective method to reduce bacterial-mediated plant disease. This review discusses the various QS-disrupting mechanisms found in both bacteria and plants, as well as the different approaches applied artificially to interfere with QS pathways and thus protect plant health.
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Affiliation(s)
- Yael Helman
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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47
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A mathematical model to investigate quorum sensing regulation and its heterogeneity in Pseudomonas syringae on leaves. ECOLOGICAL COMPLEXITY 2015. [DOI: 10.1016/j.ecocom.2014.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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48
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Taylor DL, Ante VM, Bina XR, Howard MF, Bina JE. Substrate-dependent activation of the Vibrio cholerae vexAB RND efflux system requires vexR. PLoS One 2015; 10:e0117890. [PMID: 25695834 PMCID: PMC4335029 DOI: 10.1371/journal.pone.0117890] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 01/05/2015] [Indexed: 01/08/2023] Open
Abstract
Vibrio cholerae encodes six resistance-nodulation-division (RND) efflux systems which function in antimicrobial resistance, virulence factor production, and intestinal colonization. Among the six RND efflux systems, VexAB exhibited broad substrate specificity and played a predominant role in intrinsic antimicrobial resistance. The VexAB system was encoded in an apparent three gene operon that included vexR; which encodes an uncharacterized TetR family regulator. In this work we examined the role of vexR in vexRAB expression. We found that VexR bound to the vexRAB promoter and vexR deletion resulted in decreased vexRAB expression and increased susceptibility to VexAB antimicrobial substrates. Substrate-dependent induction of vexRAB was dependent on vexR and episomal vexR expression provided a growth advantage in the presence of the VexAB substrate deoxycholate. The expression of vexRAB increased, in a vexR-dependent manner, in response to the loss of RND efflux activity. This suggested that VexAB may function to export intracellular metabolites. Support for this hypothesis was provided by data showing that vexRAB was upregulated in several metabolic mutants including tryptophan biosynthetic mutants that were predicted to accumulate indole. In addition, vexRAB was found to be upregulated in response to exogenous indole and to contribute to indole resistance. The collective results indicate that vexR is required for vexRAB expression in response to VexAB substrates and that the VexAB RND efflux system modulates the intracellular levels of metabolites that could otherwise accumulate to toxic levels.
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Affiliation(s)
- Dawn L. Taylor
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, Pittsburgh, Pennsylvania, United States of America
| | - Vanessa M. Ante
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, Pittsburgh, Pennsylvania, United States of America
| | - X. Renee Bina
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, Pittsburgh, Pennsylvania, United States of America
| | - Mondraya F. Howard
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, Pittsburgh, Pennsylvania, United States of America
| | - James E. Bina
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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49
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Kato T, Morohoshi T, Someya N, Ikeda T. The ppuI-rsaL-ppuR quorum-sensing system regulates cellular motility, pectate lyase activity, and virulence in potato opportunistic pathogen Pseudomonas sp. StFLB209. Biosci Biotechnol Biochem 2014; 79:673-80. [PMID: 25485871 DOI: 10.1080/09168451.2014.988679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Pseudomonas sp. StFLB209 was isolated from potato leaf as an N-acylhomoserine lactone (AHL)-producing bacterium and showed a close phylogenetic relationship with P. cichorii, a known plant pathogen. Although there are no reports of potato disease caused by pseudomonads in Japan, StFLB209 was pathogenic to potato leaf. In this study, we reveal the complete genome sequence of StFLB209, and show that the strain possesses a ppuI-rsaL-ppuR quorum-sensing system, the sequence of which shares a high similarity with that of Pseudomonas putida. Disruption of ppuI results in a loss of AHL production as well as remarkable reduction in motility. StFLB209 possesses strong pectate lyase activity and causes maceration on potato tuber and leaf, which was slightly reduced in the ppuI mutant. These results suggest that the quorum-sensing system is well conserved between StFLB209 and P. putida and that the system is essential for motility, full pectate lyase activity, and virulence in StFLB209.
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Affiliation(s)
- Taro Kato
- a Department of Material and Environmental Chemistry, Graduate School of Engineering , Utsunomiya University , Utsunomiya , Japan
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50
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The TetR-type MfsR protein of the integrative and conjugative element (ICE) ICEclc controls both a putative efflux system and initiation of ICE transfer. J Bacteriol 2014; 196:3971-9. [PMID: 25182498 DOI: 10.1128/jb.02129-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Integrative and conjugating elements (ICE) are self-transferable DNAs widely present in bacterial genomes, which often carry a variety of auxiliary genes of potential adaptive benefit. One of the model ICE is ICEclc, an element originally found in Pseudomonas knackmussii B13 and known for its propensity to provide its host with the capacity to metabolize chlorocatechols and 2-aminophenol. In this work, we studied the mechanism and target of regulation of MfsR, a TetR-type repressor previously found to exert global control on ICEclc horizontal transfer. By using a combination of ICEclc mutant and transcriptome analysis, gene reporter fusions, and DNA binding assays, we found that MfsR is a repressor of both its own expression and that of a gene cluster putatively coding for a major facilitator superfamily efflux system on ICEclc (named mfsABC). Phylogenetic analysis suggests that mfsR was originally located immediately adjacent to the efflux pump genes but became displaced from its original cis target DNA by a gene insertion. This resulted in divergence of the original bidirectional promoters into two separated individual regulatory units. Deletion of mfsABC did not result in a strong phenotype, and despite screening a large number of compounds and conditions, we were unable to define the precise current function or target of the putative efflux pump. Our data reconstruct how the separation of an ancestor mfsR-mfsABC system led to global control of ICEclc transfer by MfsR.
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