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Zhang Y, Zhao X, Wang J, Liao L, Qin H, Zhang R, Li C, He Y, Huang S. VmsR, a LuxR-Type Regulator, Contributes to Virulence, Cell Motility, Extracellular Polysaccharide Production and Biofilm Formation in Xanthomonas oryzae pv. oryzicola. Int J Mol Sci 2024; 25:7595. [PMID: 39062838 PMCID: PMC11277528 DOI: 10.3390/ijms25147595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Revised: 07/05/2024] [Accepted: 07/06/2024] [Indexed: 07/28/2024] Open
Abstract
LuxR-type regulators play pivotal roles in regulating numerous bacterial processes, including bacterial motility and virulence, thereby exerting a significant influence on bacterial behavior and pathogenicity. Xanthomonas oryzae pv. oryzicola, a rice pathogen, causes bacterial leaf streak. Our research has identified VmsR, which is a response regulator of the two-component system (TCS) that belongs to the LuxR family. These findings of the experiment reveal that VmsR plays a crucial role in regulating pathogenicity, motility, biofilm formation, and the production of extracellular polysaccharides (EPSs) in Xoc GX01. Notably, our study shows that the vmsR mutant exhibits a reduced swimming motility but an enhanced swarming motility. Furthermore, this mutant displays decreased virulence while significantly increasing EPS production and biofilm formation. We have uncovered that VmsR directly interacts with the promoter regions of fliC and fliS, promoting their expression. In contrast, VmsR specifically binds to the promoter of gumB, resulting in its downregulation. These findings indicate that the knockout of vmsR has profound effects on virulence, motility, biofilm formation, and EPS production in Xoc GX01, providing insights into the intricate regulatory network of Xoc.
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Affiliation(s)
- Yaqi Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (Y.Z.); (X.Z.); (J.W.); (L.L.); (H.Q.); (R.Z.); (C.L.)
| | - Xiyao Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (Y.Z.); (X.Z.); (J.W.); (L.L.); (H.Q.); (R.Z.); (C.L.)
| | - Jiuxiang Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (Y.Z.); (X.Z.); (J.W.); (L.L.); (H.Q.); (R.Z.); (C.L.)
| | - Lindong Liao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (Y.Z.); (X.Z.); (J.W.); (L.L.); (H.Q.); (R.Z.); (C.L.)
| | - Huajun Qin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (Y.Z.); (X.Z.); (J.W.); (L.L.); (H.Q.); (R.Z.); (C.L.)
| | - Rongbo Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (Y.Z.); (X.Z.); (J.W.); (L.L.); (H.Q.); (R.Z.); (C.L.)
| | - Changyu Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (Y.Z.); (X.Z.); (J.W.); (L.L.); (H.Q.); (R.Z.); (C.L.)
| | - Yongqiang He
- College of Agronomy, Guangxi University, Nanning 530004, China
| | - Sheng Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (Y.Z.); (X.Z.); (J.W.); (L.L.); (H.Q.); (R.Z.); (C.L.)
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2
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Chávez-Moctezuma MP, Martínez-Cámara R, Hernández-Salmerón J, Moreno-Hagelsieb G, Santoyo G, Valencia-Cantero E. Comparative genomic and functional analysis of Arthrobacter sp. UMCV2 reveals the presence of luxR-related genes inducible by the biocompound N, N-dimethylhexadecilamine. Front Microbiol 2022; 13:1040932. [PMID: 36386619 PMCID: PMC9659744 DOI: 10.3389/fmicb.2022.1040932] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 10/10/2022] [Indexed: 09/29/2023] Open
Abstract
Quorum sensing (QS) is a bacterial cell-cell communication system with genetically regulated mechanisms dependent on cell density. Canonical QS systems in gram-negative bacteria possess an autoinducer synthase (LuxI family) and a transcriptional regulator (LuxR family) that respond to an autoinducer molecule. In Gram-positive bacteria, the LuxR transcriptional regulators "solo" (not associated with a LuxI homolog) may play key roles in intracellular communication. Arthrobacter sp. UMCV2 is an actinobacterium that promotes plant growth by emitting the volatile organic compound N, N-dimethylhexadecylamine (DMHDA). This compound induces iron deficiency, defense responses in plants, and swarming motility in Arthrobacter sp. UMCV2. In this study, the draft genome of this bacterium was assembled and compared with the genomes of type strains of the Arthrobacter genus, finding that it does not belong to any previously described species. Genome explorations also revealed the presence of 16 luxR-related genes, but no luxI homologs were discovered. Eleven of these sequences possess the LuxR characteristic DNA-binding domain with a helix-turn-helix motif and were designated as auto-inducer-related regulators (AirR). Four sequences possessed LuxR analogous domains and were designated as auto-inducer analogous regulators (AiaR). When swarming motility was induced with DMHDA, eight airR genes and two aiaR genes were upregulated. These results indicate that the expression of multiple luxR-related genes is induced in actinobacteria, such as Arthrobacter sp. UMCV2, by the action of the bacterial biocompound DMHDA when QS behavior is produced.
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Affiliation(s)
| | - Ramiro Martínez-Cámara
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
- Tecnológico Nacional de México, Morelia, Michoacán, Mexico
| | | | | | - Gustavo Santoyo
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
| | - Eduardo Valencia-Cantero
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
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3
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Fan Q, Wang H, Mao C, Li J, Zhang X, Grenier D, Yi L, Wang Y. Structure and Signal Regulation Mechanism of Interspecies and Interkingdom Quorum Sensing System Receptors. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:429-445. [PMID: 34989570 DOI: 10.1021/acs.jafc.1c04751] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Quorum sensing (QS) is a signaling mechanism for cell-to-cell communication between bacteria, fungi, and even eukaryotic hosts such as plant and animal cells. Bacteria in real life do not exist as isolated organisms but are found in complex, dynamic, and microecological environments. The study of interspecies QS and interkingdom QS is a valuable approach for exploring bacteria-bacteria interactions and bacteria-host interaction mechanisms and has received considerable attention from researchers. The correct combination of QS signals and receptors is key to initiating the QS process. Compared with intraspecies QS, the signal regulation mechanism of interspecies QS and interkingdom QS is often more complicated, and the distribution of receptors is relatively wide. The present review focuses on the latest progress with respect to the distribution, structure, and signal transduction of interspecies and interkingdom QS receptors and provides a guide for the investigation of new QS receptors in the future.
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Affiliation(s)
- Qingying Fan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Haikun Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Chenlong Mao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Jinpeng Li
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Xiaoling Zhang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Daniel Grenier
- Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec G1 V 0A6, Canada
| | - Li Yi
- College of Life Science, Luoyang Normal University, Luoyang 471023, China
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
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4
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Connolly JA, Harcombe WR, Smanski MJ, Kinkel LL, Takano E, Breitling R. Harnessing intercellular signals to engineer the soil microbiome. Nat Prod Rep 2021; 39:311-324. [PMID: 34850800 DOI: 10.1039/d1np00034a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Covering: Focus on 2015 to 2020Plant and soil microbiomes consist of diverse communities of organisms from across kingdoms and can profoundly affect plant growth and health. Natural product-based intercellular signals govern important interactions between microbiome members that ultimately regulate their beneficial or harmful impacts on the plant. Exploiting these evolved signalling circuits to engineer microbiomes towards beneficial interactions with crops is an attractive goal. There are few reports thus far of engineering the intercellular signalling of microbiomes, but this article argues that it represents a tremendous opportunity for advancing the field of microbiome engineering. This could be achieved through the selection of synergistic consortia in combination with genetic engineering of signal pathways to realise an optimised microbiome.
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Affiliation(s)
- Jack A Connolly
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
| | - William R Harcombe
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Evolution, and Behaviour, University of Minnesota, Twin-Cities Saint Paul, MN55108, USA
| | - Michael J Smanski
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA
| | - Linda L Kinkel
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Plant Pathology, University of Minnesota, Twin-Cities, Saint Paul, MN 55108, USA
| | - Eriko Takano
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
| | - Rainer Breitling
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
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Abstract
LuxR solos are related to quorum sensing (QS) LuxR family regulators; however, they lack a cognate LuxI family protein. LuxR solos are widespread and almost exclusively found in proteobacteria. In this study, we investigated the distribution and conservation of LuxR solos in the fluorescent pseudomonads group. Our analysis of more than 600 genomes revealed that the majority of fluorescent Pseudomonas spp. carry one or more LuxR solos, occurring considerably more frequently than complete LuxI/LuxR archetypical QS systems. Based on the adjacent gene context and conservation of the primary structure, nine subgroups of LuxR solos have been identified that are likely to be involved in the establishment of communication networks. Modeling analysis revealed that the majority of subgroups shows some substitutions at the invariant amino acids of the ligand-binding pocket of QS LuxRs, raising the possibility of binding to non-acyl-homoserine lactone (AHL) ligands. Several mutants and gene expression studies on some LuxR solos belonging to different subgroups were performed in order to shed light on their response. The commonality of LuxR solos among fluorescent pseudomonads is an indication of their important role in cell-cell signaling. IMPORTANCE Cell-cell communication in bacteria is being extensively studied in simple settings and uses chemical signals and cognate regulators/receptors. Many Gram-negative proteobacteria use acyl-homoserine lactones (AHLs) synthesized by LuxI family proteins and cognate LuxR-type receptors to regulate their quorum sensing (QS) target loci. AHL-QS circuits are the best studied QS systems; however, many proteobacterial genomes also contain one or more LuxR solos, which are QS-related LuxR proteins which are unpaired to a cognate LuxI. A few LuxR solos have been implicated in intraspecies, interspecies, and interkingdom signaling. Here, we report that LuxR solo homologs occur considerably more frequently than complete LuxI/LuxR QS systems within the Pseudomonas fluorescens group of species and that they are characterized by different genomic organizations and primary structures and can be subdivided into several subgroups. The P. fluorescens group consists of more than 50 species, many of which are found in plant-associated environments. The role of LuxR solos in cell-cell signaling in fluorescent pseudomonads is discussed.
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Structural basis for a bacterial Pip system plant effector recognition protein. Proc Natl Acad Sci U S A 2021; 118:2019462118. [PMID: 33649224 DOI: 10.1073/pnas.2019462118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A number of plant-associated proteobacteria have LuxR family transcription factors that we refer to as PipR subfamily members. PipR proteins play roles in interactions between bacteria and their plant hosts, and some are important for bacterial virulence of plants. We identified an ethanolamine derivative, N-(2-hydroxyethyl)-2-(2-hydroxyethylamino) acetamide (HEHEAA), as a potent effector of PipR-mediated gene regulation in the plant endophyte Pseudomonas GM79. HEHEAA-dependent PipR activity requires an ATP-binding cassette-type active transport system, and the periplasmic substrate-binding protein (SBP) of that system binds HEHEAA. To begin to understand the molecular basis of PipR system responses to plant factors we crystallized a HEHEAA-responsive SBP in the free- and HEHEAA-bound forms. The SBP, which is similar to peptide-binding SBPs, was in a closed conformation. A narrow cavity at the interface of its two lobes is wide enough to bind HEHEAA, but it cannot accommodate peptides with side chains. The polar atoms of HEHEAA are recognized by hydrogen-bonding interactions, and additional SBP residues contribute to the binding site. This binding mode was confirmed by a structure-based mutational analysis. We also show that a closely related SBP from the plant pathogen Pseudomonas syringae pv tomato DC3000 does not recognize HEHEAA. However, a single amino acid substitution in the presumed effector-binding pocket of the P. syringae SBP converted it to a weak HEHEAA-binding protein. The P. syringae PipR depends on a plant effector for activity, and our findings imply that different PipR-associated SBPs bind different effectors.
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Pan H, Pierson LS, Pierson EA. PcsR2 Is a LuxR-Type Regulator That Is Upregulated on Wheat Roots and Is Unique to Pseudomonas chlororaphis. Front Microbiol 2020; 11:560124. [PMID: 33244313 PMCID: PMC7683790 DOI: 10.3389/fmicb.2020.560124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 10/09/2020] [Indexed: 11/13/2022] Open
Abstract
LuxR solos are common in plant-associated bacteria and increasingly recognized for playing important roles in plant-microbe interkingdom signaling. Unlike the LuxR-type transcriptional regulators of prototype LuxR/LuxI quorum sensing systems, luxR solos do not have a LuxI-type autoinducer synthase gene associated with them. LuxR solos in plant-pathogenic bacteria are important for virulence and in plant endosymbionts contribute to symbiosis. In the present study, we characterized an atypical LuxR solo, PcsR2, in the biological control species Pseudomonas chlororaphis 30-84 that is highly conserved among sequenced P. chlororaphis strains. Unlike most LuxR solos in the plant-associated bacteria characterized to date, pcsR2 is not associated with a proline iminopeptidase gene and the protein has an atypical N-terminal binding domain. We created a pcsR2 deletion mutant and used quantitative RT-PCR to show that the expression of pcsR2 and genes in the operon immediately downstream was upregulated ∼10-fold when the wild type strain was grown on wheat roots compared to planktonic culture. PcsR2 was involved in upregulation. Using a GFP transcriptional reporter, we found that expression of pcsR2 responded specifically to root-derived substrates as compared to leaf-derived substrates but not to endogenous AHLs. Compared to the wild type, the mutant was impaired in the ability to utilize root carbon and nitrogen sources in wheat root macerate and to colonize wheat roots. Phenazine production and most biofilm traits previously shown to be correlated with phenazine production also were diminished in the mutant. Gene expression of several of the proteins in the phenazine regulatory network including PhzR, Pip (phenazine inducing protein) and RpeA/RpeB were reduced in the mutant, and overexpression of these genes in trans restored phenazine production in the mutant to wild-type levels, indicating PcsR2 affects the activity of the these regulatory genes upstream of RpeA/RpeB via an undetermined mechanism. Our results indicate PcsR2 upregulates the expression of the adjacent operon in response to unknown wheat root-derived signals and belongs to a novel subfamily of LuxR-type transcriptional regulators found in sequenced P. chlororaphis strains.
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Affiliation(s)
- Huiqiao Pan
- Molecular and Environmental Plant Sciences Program, Texas A&M University, College Station, TX, United States.,Department of Horticulture Sciences, Texas A&M University, College Station, TX, United States
| | - Leland S Pierson
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
| | - Elizabeth A Pierson
- Molecular and Environmental Plant Sciences Program, Texas A&M University, College Station, TX, United States.,Department of Horticulture Sciences, Texas A&M University, College Station, TX, United States.,Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
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8
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LuxR Solos in the Plant Endophyte Kosakonia sp. Strain KO348. Appl Environ Microbiol 2020; 86:AEM.00622-20. [PMID: 32332134 PMCID: PMC7301841 DOI: 10.1128/aem.00622-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 04/10/2020] [Indexed: 12/30/2022] Open
Abstract
Cell-cell signaling in bacteria allows a synchronized and coordinated behavior of a microbial community. LuxR solos represent a subfamily of proteins in proteobacteria which most commonly detect and respond to signals produced exogenously by other microbes or eukaryotic hosts. Here, we report that a plant-beneficial bacterial endophyte belonging to the novel genus of Kosakonia possesses two LuxR solos; one is involved in the detection of exogenous N-acyl homoserine lactone quorum sensing signals and the other in detecting a compound(s) produced by the host plant. These two Kosakonia LuxR solos are therefore most likely involved in interspecies and interkingdom signaling. Endophytes are microorganisms that live inside plants and are often beneficial for the host. Kosakonia is a novel bacterial genus that includes several species that are diazotrophic and plant associated. This study revealed two quorum sensing-related LuxR solos, designated LoxR and PsrR, in the plant endophyte Kosakonia sp. strain KO348. LoxR modeling and biochemical studies demonstrated that LoxR binds N-acyl homoserine lactones (AHLs) in a promiscuous way. PsrR, on the other hand, belongs to the subfamily of plant-associated-bacterium (PAB) LuxR solos that respond to plant compounds. Target promoter studies as well as modeling and phylogenetic comparisons suggest that PAB LuxR solos are likely to respond to different plant compounds. Finally, LoxR is involved in the regulation of T6SS and PsrR plays a role in root endosphere colonization. IMPORTANCE Cell-cell signaling in bacteria allows a synchronized and coordinated behavior of a microbial community. LuxR solos represent a subfamily of proteins in proteobacteria which most commonly detect and respond to signals produced exogenously by other microbes or eukaryotic hosts. Here, we report that a plant-beneficial bacterial endophyte belonging to the novel genus of Kosakonia possesses two LuxR solos; one is involved in the detection of exogenous N-acyl homoserine lactone quorum sensing signals and the other in detecting a compound(s) produced by the host plant. These two Kosakonia LuxR solos are therefore most likely involved in interspecies and interkingdom signaling.
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9
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Liu W, Li Y, Bai X, Wu H, Bian L, Hu X. LuxR-Type Regulator AclR1 of Azorhizobium caulinodans Regulates Cyclic di-GMP and Numerous Phenotypes in Free-Living and Symbiotic States. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:528-538. [PMID: 31789101 DOI: 10.1094/mpmi-10-19-0306-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
LuxR-type regulators play important roles in transcriptional regulation in bacteria and control various biological processes. A genome sequence analysis showed the existence of seven LuxR-type regulators in Azorhizobium caulinodans ORS571, an important nitrogen-fixing bacterium in both its free-living state and in symbiosis with its host, Sesbania rostrata. However, the functional mechanisms of these regulators remain unclear. In this study, we identified a LuxR-type regulator that contains a cheY-homologous receiver (REC) domain in its N terminus and designated it AclR1. Interestingly, phylogenetic analysis revealed that AclR1 exhibited relatively close evolutionary relationships with MalT/GerE/FixJ/NarL family proteins. Functional analysis of an aclR1 deletion mutant (ΔaclR1) in the free-living state showed that AclR1 positively regulated cell motility and flocculation but negatively regulated exopolysaccharide production, biofilm formation, and second messenger cyclic diguanylate (c-di-GMP)-related gene expression. In the symbiotic state, the ΔaclR1 mutant was defective in competitive colonization and nodulation on host plants. These results suggested that AclR1 could provide bacteria with the ability to compete effectively for symbiotic nodulation. Overall, our results show that the REC-LuxR-type regulator AclR1 regulates numerous phenotypes both in the free-living state and during host plant symbiosis.
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Affiliation(s)
- Wei Liu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yan Li
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xue Bai
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- College of Life Sciences, Yantai University, Yantai, China
| | - Haiguang Wu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- College of Life Sciences, Yantai University, Yantai, China
| | - Lanxing Bian
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- College of Life Sciences, Yantai University, Yantai, China
| | - Xiaoke Hu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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10
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Xu G. Evolution of LuxR solos in bacterial communication: receptors and signals. Biotechnol Lett 2019; 42:181-186. [PMID: 31732826 DOI: 10.1007/s10529-019-02763-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 11/11/2019] [Indexed: 12/14/2022]
Abstract
Cell-cell communication in bacteria needs chemical signals and cognate receptors. Many Gram-negative bacteria use acyl-homoserine lactones (AHLs) and cognate LuxR-type receptors to regulate their quorum sensing (QS) systems. The signal synthase-receptor (LuxI-LuxR) pairs may have co-evolved together. However, many LuxR solo (orphan LuxR) regulators sense more signals than just AHLs, and expand the regulatory networks for inter-species and inter-kingdom communication. Moreover, there are also some QS regulators from the TetR family. LuxR solo regulators might have evolved by gene duplication and horizontal gene transfer. An increased understanding of the evolutionary roles of QS regulators would be helpful for engineering of cell-cell communication circuits in bacteria.
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Affiliation(s)
- Gangming Xu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
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11
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Zhang Y, Wu G, Palmer I, Wang B, Qian G, Fu ZQ, Liu F. The Role of a Host-Induced Arginase of Xanthomonas oryzae pv. oryzae in Promoting Virulence on Rice. PHYTOPATHOLOGY 2019; 109:1869-1877. [PMID: 31290730 DOI: 10.1094/phyto-02-19-0058-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The plant bacterial pathogen Xanthomonas oryzae pv. oryzae causes bacterial blight of rice, which is one of the most destructive rice diseases prevalent in Asia and parts of Africa. Despite many years of research, how X. oryzae pv. oryzae causes bacterial blight of rice is still not completely understood. Here, we show that the loss of the rocF gene caused a significant decrease in the virulence of X. oryzae pv. oryzae in the susceptible rice cultivar IR24. Bioinformatics analysis demonstrated that rocF encodes arginase. Quantitative real-time PCR and Western blot assays revealed that rocF expression was significantly induced by rice and arginine. The rocF deletion mutant strain showed elevated sensitivity to hydrogen peroxide, reduced extracellular polysaccharide (EPS) production, and reduced biofilm formation, all of which are important determinants for the full virulence of X. oryzae pv. oryzae, compared with the wild-type strain. Taken together, the results of this study revealed a mechanism by which a bacterial arginase is required for the full virulence of X. oryzae pv. oryzae on rice because of its contribution to tolerance to reactive oxygen species, EPS production, and biofilm formation.
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Affiliation(s)
- Yuqiang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, Nanjing 210095, P.R. China
| | - Guichun Wu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, P.R. China
| | - Ian Palmer
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, U.S.A
| | - Bo Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, Nanjing 210095, P.R. China
| | - Guoliang Qian
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, Nanjing 210095, P.R. China
| | - Zheng Qing Fu
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, U.S.A
| | - Fengquan Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, Nanjing 210095, P.R. China
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, P.R. China
- School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, P.R. China
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12
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Nobori T, Mine A, Tsuda K. Molecular networks in plant-pathogen holobiont. FEBS Lett 2018; 592:1937-1953. [PMID: 29714033 DOI: 10.1002/1873-3468.13071] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/13/2018] [Accepted: 04/23/2018] [Indexed: 12/31/2022]
Abstract
Plant immune receptors enable detection of a multitude of microbes including pathogens. The recognition of microbes activates various plant signaling pathways, such as those mediated by phytohormones. Over the course of coevolution with microbes, plants have expanded their repertoire of immune receptors and signaling components, resulting in highly interconnected plant immune networks. These immune networks enable plants to appropriately respond to different types of microbes and to coordinate immune responses with developmental programs and environmental stress responses. However, the interconnectivity in plant immune networks is exploited by microbial pathogens to promote pathogen fitness in plants. Analogous to plant immune networks, virulence-related pathways in bacterial pathogens are also interconnected. Accumulating evidence implies that some plant-derived compounds target bacterial virulence networks. Thus, the plant immune and bacterial virulence networks intimately interact with each other. Here, we highlight recent insights into the structures of the plant immune and bacterial virulence networks and the interactions between them. We propose that small molecules derived from plants and/or bacterial pathogens connect the two molecular networks, forming supernetworks in the plant-bacterial pathogen holobiont.
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Affiliation(s)
- Tatsuya Nobori
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Akira Mine
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Kusatsu, Japan.,JST, PRESTO, Kawaguchi-shi, Japan
| | - Kenichi Tsuda
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
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Ankyrin-Like Protein AnkB Interacts with CatB, Affects Catalase Activity, and Enhances Resistance of Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola to Phenazine-1-Carboxylic Acid. Appl Environ Microbiol 2018; 84:AEM.02145-17. [PMID: 29180371 DOI: 10.1128/aem.02145-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/18/2017] [Indexed: 02/07/2023] Open
Abstract
Xanthomonas oryzae pv. oryzae, which causes rice bacterial leaf blight, and Xanthomonas oryzae pv. oryzicola, which causes rice bacterial leaf streak, are important plant-pathogenic bacteria. A member of the adaptor protein family, ankyrin protein, has been investigated largely in humans but rarely in plant-pathogenic bacteria. In this study, a novel ankyrin-like protein, AnkB, was identified in X. oryzae pv. oryzae and X. oryzae pv. oryzicola. The expression of ankB was significantly upregulated when these bacteria were treated with phenazine-1-carboxylic acid (PCA). ankB is located 58 bp downstream of the gene catB (which encodes a catalase) in both bacteria, and the gene expression of catB and catalase activity were reduced following ankB deletion in X. oryzae pv. oryzae and X. oryzae pv. oryzicola. Furthermore, we demonstrated that AnkB directly interacts with CatB by glutathione S-transferase (GST) pulldown assays. Deletion of ankB increased the sensitivity of X. oryzae pv. oryzae and X. oryzae pv. oryzicola to H2O2 and PCA, decreased bacterial biofilm formation, swimming ability, and exopolysaccharide (EPS) production, and also reduced virulence on rice. Together our results indicate that the ankyrin-like protein AnkB has important and conserved roles in antioxidant systems and pathogenicity in X. oryzae pv. oryzae and X. oryzae pv. oryzicola.IMPORTANCE This study demonstrates that the ankyrin protein AnkB directly interacts with catalase CatB in Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola. Ankyrin protein AnkB can affect the gene expression of catB, catalase activity, and sensitivity to H2O2 In Xanthomonas spp., the locations of genes ankB and catB and the amino acid sequence of AnkB are highly conserved. It is suggested that in prokaryotes, AnkB plays a conserved role in the defense against oxidative stress.
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14
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Singh A, Gupta R, Tandon S, Prateeksha, Pandey R. Anti-biofilm and anti-virulence potential of 3,7-dimethyloct-6-enal derived from Citrus hystrix against bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae. Microb Pathog 2017; 115:264-271. [PMID: 29273511 DOI: 10.1016/j.micpath.2017.12.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/18/2017] [Accepted: 12/18/2017] [Indexed: 11/28/2022]
Abstract
The present investigation for the first time explains the anti biofilm and anti virulence potential of Kaffir lime oil (KLO) and its major constituent, Citronellal (3,7-dimethyloct-6-enal) against Xanthomonas oryzae pv. oryzae, causal organism of bacterial blight disease of rice. KLO at 500 ppm showed potential activity against X. oryzae pv. oryzae. Among the major components identified, citronellal (CIT) at 75 μM concentration was found to significantly inhibit biofilm along with the swimming and swarming potential of X. oryzae pv. oryzae. In contrary, CIT did not affect the metabolic status and growth kinetics of the bacterial cells. Gene expression analysis showed down regulation in motA, cheD, cheY, flgF, gumC, xylanase, endogluconase, cellulose, cellobiosidase, virulence and rpfF transcript levels by citronellal treatment. However, an insignificant effect of 75 μM CIT treatment was observed on motB, flgE, pilA, estY, pglA, protease and lytic genes expression. Finally, the observations recorded were in confirmity with the virulence leaf clip test as lesion length was significantly decreased (39%) in CIT treatment as compared to the control leaves inoculated with only X. oryzae pv. oryzae. Overall, the findings obtained advocate the use of CIT for promising anti biofilm and anti virulence activity which in turn can be used for managing the blight disease in rice.
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Affiliation(s)
- Akanksha Singh
- Department of Microbial Technology and Nematology, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow, 226015, India
| | - Rupali Gupta
- Department of Microbial Technology and Nematology, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow, 226015, India
| | - Sudeep Tandon
- Chemical Processing Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, 226 015, India
| | - Prateeksha
- Pharmacognosy & Ethnopharmacology Division, CSIR-National Botanical Research Institute, Lucknow, 226001, India
| | - Rakesh Pandey
- Department of Microbial Technology and Nematology, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow, 226015, India.
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15
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Wu G, Su P, Wang B, Zhang Y, Qian G, Liu F. Novel Insights into Tat Pathway in Xanthomonas oryzae pv. oryzae Stress Adaption and Virulence: Identification and Characterization of Tat-Dependent Translocation Proteins. PHYTOPATHOLOGY 2017; 107:1011-1021. [PMID: 28699375 DOI: 10.1094/phyto-02-17-0053-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Xanthomonas oryzae pv. oryzae, an economically important bacterium, causes a serious disease in rice production worldwide called bacterial leaf blight. How X. oryzae pv. oryzae infects rice and causes symptoms remains incompletely understood. Our earlier works demonstrated that the twin-arginine translocation (Tat) pathway plays an vital role in X. oryzae pv. oryzae fitness and virulence but the underlying mechanism is unknown. In this study, we used strain PXO99A as a working model, and identified 15 potential Tat-dependent translocation proteins (TDTP) by using comparative proteomics and bioinformatics analyses. Combining systematic mutagenesis, phenotypic characterization, and gene expression, we found that multiple TDTP play key roles in X. oryzae pv. oryzae adaption or virulence. In particular, four TDTP (PXO_02203, PXO_03477, PXO_02523, and PXO_02951) were involved in virulence, three TDTP (PXO_02203, PXO_03477, and PXO_02523) contributed to colonization in planta, one TDTP (PXO_02671) had a key role in attachment to leaf surface, four TDTP (PXO_02523, PXO_02951, PXO_03132, and PXO_03841) were involved in tolerance to multiple stresses, and two TDTP (PXO_02523 and PXO_02671) were required for full swarming motility. These findings suggest that multiple TDTP may have differential contributions to involvement of the Tat pathway in X. oryzae pv. oryzae adaption, physiology, and pathogenicity.
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Affiliation(s)
- Guichun Wu
- All authors: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, P.R. China; and sixth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Panpan Su
- All authors: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, P.R. China; and sixth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Bo Wang
- All authors: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, P.R. China; and sixth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Yuqiang Zhang
- All authors: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, P.R. China; and sixth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Guoliang Qian
- All authors: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, P.R. China; and sixth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
| | - Fengquan Liu
- All authors: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China/Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, P.R. China; and sixth author: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, P.R. China
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16
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Interkingdom signaling in plant-microbe interactions. SCIENCE CHINA-LIFE SCIENCES 2017; 60:785-796. [PMID: 28755299 DOI: 10.1007/s11427-017-9092-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/04/2017] [Indexed: 12/18/2022]
Abstract
The widespread communications between prokaryotes and eukaryotes via signaling molecules are believed to affect gene expression in both partners. During the communication process, the contacted organisms produce and release small molecules that establish communication channels between two kingdoms-this procedure is known as interkingdom signaling. Interkingdom communications are widespread between pathogenic or beneficial bacteria and their host plants, with diversified outcomes depending on the specific chemical-triggered signaling pathways. Deciphering the signals or language of this interkingdom communication and uncovering the underlying mechanisms are major current challenges in this field. It is evident that diverse signaling molecules can be produced or derived from bacteria and plants, and researchers have sought to identify these signals and explore the mechanisms of the signaling pathways. The results of such studies will lead to the development of strategies to improve plant disease resistance through controlling interkingdom signals, rather than directly killing the pathogenic bacteria. Also, the identification of signals produced by beneficial bacteria will be useful for agricultural applications. In this review, we summarize the recent progress of cross-kingdom interactions between plant and bacteria, and how LuxR-family transcription factors in plant associated bacterial quorum sensing system are involved in the interkingdom signaling.
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17
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Song Z, Zhao Y, Qian G, Odhiambo BO, Liu F. Novel insights into the regulatory roles of gene hshB in Xanthomonas oryzae pv. oryzicola. Res Microbiol 2016; 168:165-173. [PMID: 27810475 DOI: 10.1016/j.resmic.2016.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/15/2016] [Accepted: 10/24/2016] [Indexed: 12/16/2022]
Abstract
Xanthomonas oryzae pv. oryzicola causes leaf streak disease of rice. The gene hshB is a newly identified virulence-associated gene that is co-regulated by diffusible signal factor signaling and global regulator Clp in X. oryzae pv. oryzicola. Our previous study showed that mutation of hshB remarkably impaired the virulence, extracellular protease activity, extracellular polysaccharide production and resistance to oxidative stress of X. oryzae pv. oryzicola. In this study, the regulatory role of hshB in X. oryzae pv .oryzicola was expanded. Results showed that hshB was also required for cell swimming motility. Transcriptome analysis showed that 305 genes were significantly differentially expressed after deletion of hshB in X. oryzae pv. oryzicola. Further analysis of transcriptome data indicated that the differentially expressed genes focused on two aspects: namely, cell motility and cell signal transduction. This finding strongly identified the closely related function of hshB to cell motility and signal transduction. In addition, the mutation of hshB of X. oryzae pv. oryzicola enhanced biofilm formation. Collectively, the study showed novel functions of gene hshB in cell motility and biofilm formation by transcriptome analysis, thus expanding our understanding of the roles of gene hshB in the pathogenic X. oryzae pv. oryzicola.
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Affiliation(s)
- Zhiwei Song
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China
| | - Yancun Zhao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China
| | - Guoliang Qian
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, China
| | - Benard Omondi Odhiambo
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of Education, China
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China.
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18
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A LuxR Homolog in a Cottonwood Tree Endophyte That Activates Gene Expression in Response to a Plant Signal or Specific Peptides. mBio 2016; 7:mBio.01101-16. [PMID: 27486195 PMCID: PMC4981722 DOI: 10.1128/mbio.01101-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Homologs of the LuxR acyl-homoserine lactone (AHL) quorum-sensing signal receptor are prevalent in Proteobacteria isolated from roots of the Eastern cottonwood tree, Populus deltoides Many of these isolates possess an orphan LuxR homolog, closely related to OryR from the rice pathogen Xanthomonas oryzae OryR does not respond to AHL signals but, instead, responds to an unknown plant compound. We discovered an OryR homolog, PipR, in the cottonwood endophyte Pseudomonas sp. strain GM79. The genes adjacent to pipR encode a predicted ATP-binding cassette (ABC) peptide transporter and peptidases. We purified the putative peptidases, PipA and AapA, and confirmed their predicted activities. A transcriptional pipA-gfp reporter was responsive to PipR in the presence of plant leaf macerates, but it was not influenced by AHLs, similar to findings with OryR. We found that PipR also responded to protein hydrolysates to activate pipA-gfp expression. Among many peptides tested, the tripeptide Ser-His-Ser showed inducer activity but at relatively high concentrations. An ABC peptide transporter mutant failed to respond to leaf macerates, peptone, or Ser-His-Ser, while peptidase mutants expressed higher-than-wild-type levels of pipA-gfp in response to any of these signals. Our studies are consistent with a model where active transport of a peptidelike signal is required for the signal to interact with PipR, which then activates peptidase gene expression. The identification of a peptide ligand for PipR sets the stage to identify plant-derived signals for the OryR family of orphan LuxR proteins. IMPORTANCE We describe the transcription factor PipR from a Pseudomonas strain isolated as a cottonwood tree endophyte. PipR is a member of the LuxR family of transcriptional factors. LuxR family members are generally thought of as quorum-sensing signal receptors, but PipR is one of an emerging subfamily of LuxR family members that respond to compounds produced by plants. We found that PipR responds to a peptidelike compound, and we present a model for Pip system signal transduction. A better understanding of plant-responsive LuxR homologs and the compounds to which they respond is of general importance, as they occur in dozens of bacterial species that are associated with economically important plants and, as we report here, they also occur in members of certain root endophyte communities.
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19
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Wang R, Xu H, Du L, Chou SH, Liu H, Liu Y, Liu F, Qian G. A TonB-dependent receptor regulates antifungal HSAF biosynthesis in Lysobacter. Sci Rep 2016; 6:26881. [PMID: 27241275 PMCID: PMC4886534 DOI: 10.1038/srep26881] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/25/2016] [Indexed: 11/25/2022] Open
Abstract
Lysobacter species are Gram-negative bacteria that are emerging as new sources of antibiotics, including HSAF (Heat Stable Antifungal Factor), which was identified from L. enzymogenes with a new mode of action. LesR, a LuxR solo, was recently shown to regulate the HSAF biosynthesis via an unidentified mechanism in L. enzymogenes OH11. Here, we used a comparative proteomic approach to identify the LesR targets and found that LesR influenced the expression of 33 proteins belonging to 10 functional groups, with 9 proteins belonging to the TBDR (TonB-Dependent Receptor) family. The fundamental role of bacterial TBDR in nutrient uptake motivates us to explore their potential regulation on HSAF biosynthesis which is also modulated by nutrient condition. Six out of 9 TBDR coding genes were individually in-frame deleted. Phenotypic and gene-expression assays showed that TBDR7, whose level was lower in a strain overexpressing lesR, was involved in regulating HSAF yield. TBDR7 was not involved in the growth, but played a vital role in transcribing the key HSAF biosynthetic gene. Taken together, the current lesR-based proteomic study provides the first report that TBDR7 plays a key role in regulating antibiotic (HSAF) biosynthesis, a function which has never been found for TBDRs in bacteria.
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Affiliation(s)
- Ruping Wang
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests), Nanjing Agricultural University, Nanjing 210095, P.R. China
| | - Huiyong Xu
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests), Nanjing Agricultural University, Nanjing 210095, P.R. China
| | - Liangcheng Du
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Shan-Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Hongxia Liu
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests), Nanjing Agricultural University, Nanjing 210095, P.R. China
| | - Youzhou Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, P.R. China
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, P.R. China
| | - Guoliang Qian
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests), Nanjing Agricultural University, Nanjing 210095, P.R. China
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20
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Su J, Zou X, Huang L, Bai T, Liu S, Yuan M, Chou SH, He YW, Wang H, He J. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice. Sci Rep 2016; 6:25978. [PMID: 27193392 PMCID: PMC4872155 DOI: 10.1038/srep25978] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 04/26/2016] [Indexed: 12/28/2022] Open
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases.
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Affiliation(s)
- Jianmei Su
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xia Zou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Liangbo Huang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Tenglong Bai
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shu Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Meng Yuan
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shan-Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan
| | - Ya-Wen He
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Haihong Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510650, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
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21
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Corral-Lugo A, Daddaoua A, Ortega A, Espinosa-Urgel M, Krell T. Rosmarinic acid is a homoserine lactone mimic produced by plants that activates a bacterial quorum-sensing regulator. Sci Signal 2016; 9:ra1. [PMID: 26732761 DOI: 10.1126/scisignal.aaa8271] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Quorum sensing is a bacterial communication mechanism that controls genes, enabling bacteria to live as communities, such as biofilms. Homoserine lactone (HSL) molecules function as quorum-sensing signals for Gram-negative bacteria. Plants also produce previously unidentified compounds that affect quorum sensing. We identified rosmarinic acid as a plant-derived compound that functioned as an HSL mimic. In vitro assays showed that rosmarinic acid bound to the quorum-sensing regulator RhlR of Pseudomonas aeruginosa PAO1 and competed with the bacterial ligand N-butanoyl-homoserine lactone (C4-HSL). Furthermore, rosmarinic acid stimulated a greater increase in RhlR-mediated transcription in vitro than that of C4-HSL. In P. aeruginosa, rosmarinic acid induced quorum sensing-dependent gene expression and increased biofilm formation and the production of the virulence factors pyocyanin and elastase. Because P. aeruginosa PAO1 infection induces rosmarinic acid secretion from plant roots, our results indicate that rosmarinic acid secretion is a plant defense mechanism to stimulate a premature quorum-sensing response. P. aeruginosa is a ubiquitous pathogen that infects plants and animals; therefore, identification of rosmarinic acid as an inducer of premature quorum-sensing responses may be useful in agriculture and inform human therapeutic strategies.
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Affiliation(s)
- Andrés Corral-Lugo
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Abdelali Daddaoua
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Alvaro Ortega
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Manuel Espinosa-Urgel
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, 18008 Granada, Spain.
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22
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Gardiner M, Fernandes ND, Nowakowski D, Raftery M, Kjelleberg S, Zhong L, Thomas T, Egan S. VarR controls colonization and virulence in the marine macroalgal pathogen Nautella italica R11. Front Microbiol 2015; 6:1130. [PMID: 26528274 PMCID: PMC4602140 DOI: 10.3389/fmicb.2015.01130] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/28/2015] [Indexed: 01/16/2023] Open
Abstract
There is increasing evidence to suggest that macroalgae (seaweeds) are susceptible to infectious disease. However, to date, little is known about the mechanisms that facilitate the colonization and virulence of microbial seaweed pathogens. One well-described example of a seaweed disease is the bleaching of the red alga Delisea pulchra, which can be caused by the bacterium Nautella italica R11, a member of the Roseobacter clade. This pathogen contains a unique luxR-type gene, varR, which we hypothesize controls its colonization and virulence. We show here that a varR knock-out strain is deficient in its ability to cause disease in D. pulchra and is defective in biofilm formation and attachment to a common algal polysaccharide. Moreover complementation of the varR gene in trans can restore these functions to the wild type levels. Proteomic analysis of bacterial cells in planktonic and biofilm growth highlight the potential importance of nitrogen scavenging, mobilization of energy reserves, and stress resistance in the biofilm lifestyle of N. italica R11. Moreover, we show that VarR regulates the expression of a specific subset of biofilm-associated proteins. Taken together these data suggest that VarR controls colonization and persistence of N. italica R11 on the surface of a macroalgal host and that it is an important regulator of virulence.
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Affiliation(s)
- Melissa Gardiner
- School of Biotechnology and Biomolecular Sciences, Centre for Marine Bio-Innovation, The University of New South Wales Sydney, NSW, Australia
| | - Neil D Fernandes
- School of Biotechnology and Biomolecular Sciences, Centre for Marine Bio-Innovation, The University of New South Wales Sydney, NSW, Australia
| | - Dennis Nowakowski
- School of Biotechnology and Biomolecular Sciences, Centre for Marine Bio-Innovation, The University of New South Wales Sydney, NSW, Australia
| | - Mark Raftery
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, The University of New South Wales Sydney, NSW, Australia
| | - Staffan Kjelleberg
- School of Biotechnology and Biomolecular Sciences, Centre for Marine Bio-Innovation, The University of New South Wales Sydney, NSW, Australia ; Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore Singapore
| | - Ling Zhong
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, The University of New South Wales Sydney, NSW, Australia
| | - Torsten Thomas
- School of Biotechnology and Biomolecular Sciences, Centre for Marine Bio-Innovation, The University of New South Wales Sydney, NSW, Australia
| | - Suhelen Egan
- School of Biotechnology and Biomolecular Sciences, Centre for Marine Bio-Innovation, The University of New South Wales Sydney, NSW, Australia
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da Silva DP, Patel HK, González JF, Devescovi G, Meng X, Covaceuszach S, Lamba D, Subramoni S, Venturi V. Studies on synthetic LuxR solo hybrids. Front Cell Infect Microbiol 2015; 5:52. [PMID: 26151032 PMCID: PMC4471428 DOI: 10.3389/fcimb.2015.00052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 05/26/2015] [Indexed: 11/13/2022] Open
Abstract
A sub-group of LuxR family of proteins that plays important roles in quorum sensing, a process of cell-cell communication, is widespread in proteobacteria. These proteins have a typical modular structure consisting of N-ter autoinducer binding and C-ter helix-turn-helix (HTH) DNA binding domains. The autoinducer binding domain recognizes signaling molecules which are most often N-acyl homoserine lactones (AHLs) but could also be other novel and yet unidentified molecules. In this study we carried out a series of specific domain swapping and promoter activation experiments as a first step to engineer synthetic signaling modules, taking advantage of the modularity and the versatile/diverse signal specificities of LuxR proteins. In our experiments the N-ter domains from different LuxR homologs were either interchanged or placed in tandem followed by a C-ter domain. The rational design of the hybrid proteins was supported by a structure-based homology modeling studies of three members of the LuxR family (i.e., LasR, RhlR, and OryR being chosen for their unique ligand binding specificities) and of selected chimeras. Our results reveal that these LuxR homologs were able to activate promoter elements that were not their usual targets; we also show that hybrid LuxR proteins retained the ability to recognize the signal specific for their N- ter autoinducer binding domain. However, the activity of hybrid LuxR proteins containing two AHL binding domains in tandem appears to depend on the organization and nature of the introduced domains. This study represents advances in the understanding of the modularity of LuxR proteins and provides additional possibilities to use hybrid proteins in both basic and applied synthetic biology based research.
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Affiliation(s)
- Daniel Passos da Silva
- Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy ; Centro de Ciencias da Saude, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Hitendra K Patel
- Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy
| | - Juan F González
- Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy
| | - Giulia Devescovi
- Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy
| | - Xianfa Meng
- Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy
| | - Sonia Covaceuszach
- Istituto di Cristallografia, Unità Organizzativa di Supporto di Basovizza (Trieste), Consiglio Nazionale delle Ricerche Trieste, Italy
| | - Doriano Lamba
- Istituto di Cristallografia, Unità Organizzativa di Supporto di Basovizza (Trieste), Consiglio Nazionale delle Ricerche Trieste, Italy
| | - Sujatha Subramoni
- Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy
| | - Vittorio Venturi
- Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy
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24
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Martínez P, Huedo P, Martinez-Servat S, Planell R, Ferrer-Navarro M, Daura X, Yero D, Gibert I. Stenotrophomonas maltophilia responds to exogenous AHL signals through the LuxR solo SmoR (Smlt1839). Front Cell Infect Microbiol 2015; 5:41. [PMID: 26029670 PMCID: PMC4432800 DOI: 10.3389/fcimb.2015.00041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/28/2015] [Indexed: 11/22/2022] Open
Abstract
Quorum Sensing (QS) mediated by Acyl Homoserine Lactone (AHL) molecules are probably the most widespread and studied among Gram-negative bacteria. Canonical AHL systems are composed by a synthase (LuxI family) and a regulator element (LuxR family), whose genes are usually adjacent in the genome. However, incomplete AHL-QS machinery lacking the synthase LuxI is frequently observed in Proteobacteria, and the regulator element is then referred as LuxR solo. It has been shown that certain LuxR solos participate in interspecific communication by detecting signals produced by different organisms. In the case of Stenotrophomonas maltophilia, a preliminary genome sequence analysis revealed numerous putative luxR genes, none of them associated to a luxI gene. From these, the hypothetical LuxR solo Smlt1839, here designated SmoR, presents a conserved AHL binding domain and a helix-turn-helix DNA binding motif. Its genomic organization—adjacent to hchA gene—indicate that SmoR belongs to the new family “LuxR regulator chaperone HchA-associated.” AHL-binding assays revealed that SmoR binds to AHLs in-vitro, at least to oxo-C8-homoserine lactone, and it regulates operon transcription, likely by recognizing a conserved palindromic regulatory box in the hchA upstream region. Supplementation with concentrated supernatants from Pseudomonas aeruginosa, which contain significant amounts of AHLs, promoted swarming motility in S. maltophilia. Contrarily, no swarming stimulation was observed when the P. aeruginosa supernatant was treated with the lactonase AiiA from Bacillus subtilis, confirming that AHL contributes to enhance the swarming ability of S. maltophilia. Finally, mutation of smoR resulted in a swarming alteration and an apparent insensitivity to the exogenous AHLs provided by P. aeruginosa. In conclusion, our results demonstrate that S. maltophilia senses AHLs produced by neighboring bacteria through the LuxR solo SmoR, regulating population behaviors such as swarming motility.
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Affiliation(s)
- Paula Martínez
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Pol Huedo
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Sònia Martinez-Servat
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Raquel Planell
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Mario Ferrer-Navarro
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Xavier Daura
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Catalan Institution for Research and Advanced Studies Barcelona, Spain
| | - Daniel Yero
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Isidre Gibert
- Grup de Genètica Molecular i Patogènesi Bacteriana, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain ; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Barcelona, Spain
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25
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Xu H, Zhao Y, Qian G, Liu F. XocR, a LuxR solo required for virulence in Xanthomonas oryzae pv. oryzicola. Front Cell Infect Microbiol 2015; 5:37. [PMID: 25932456 PMCID: PMC4399327 DOI: 10.3389/fcimb.2015.00037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/31/2015] [Indexed: 01/15/2023] Open
Abstract
Xanthomonas oryzae pv. oryzicola (Xoc) causes bacterial leaf streak (BLS) in rice, a serious bacterial disease of rice in Asia and parts of Africa. The virulence mechanisms of Xoc are not entirely clear and control measures for BLS are poorly developed. The solo LuxR proteins are widespread and shown to be involved in virulence in some plant associated bacteria (PAB). Here, we have cloned and characterized a PAB LuxR solo from Xoc, named as XocR. Mutation of xocR almost completely impaired the virulence ability of Xoc on host rice, but did not alter the ability to trigger HR (hypersensitive response, a programmed cell death) on non-host (plant) tobacco, suggesting the diversity of function of xocR in host and non-host plants. We also provide evidence to show that xocR is involved in the regulation of growth-independent cell motility in response to a yet-to-be-identified rice signal, as mutation of xocR impaired cell swimming motility of wild-type Rs105 in the presence but not absence of rice macerate. We further found that xocR regulated the transcription of two characterized virulence-associated genes (recN and trpE) in the presence of rice macerate. The promoter regions of recN and trpE possessed a potential binding motif (an imperfect pip box-like element) of XocR, raising the possibility that XocR might directly bind the promoter regions of these two genes to regulate their transcriptional activity. Our studies add a new member of PAB LuxR solos and also provide new insights into the role of PAB LuxR solo in the virulence of Xanthomonas species.
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Affiliation(s)
- Huiyong Xu
- Institute of Plant Protection, Jiangsu Academy of Agricultural ScienceNanjing, China
- College of Plant Protection, Nanjing Agricultural UniversityNanjing, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing, China
| | - Yancun Zhao
- Institute of Plant Protection, Jiangsu Academy of Agricultural ScienceNanjing, China
| | - Guoliang Qian
- College of Plant Protection, Nanjing Agricultural UniversityNanjing, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing, China
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural ScienceNanjing, China
- College of Plant Protection, Nanjing Agricultural UniversityNanjing, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing, China
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26
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Subramoni S, Florez Salcedo DV, Suarez-Moreno ZR. A bioinformatic survey of distribution, conservation, and probable functions of LuxR solo regulators in bacteria. Front Cell Infect Microbiol 2015; 5:16. [PMID: 25759807 PMCID: PMC4338825 DOI: 10.3389/fcimb.2015.00016] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 02/02/2015] [Indexed: 12/25/2022] Open
Abstract
LuxR solo transcriptional regulators contain both an autoinducer binding domain (ABD; N-terminal) and a DNA binding Helix-Turn-Helix domain (HTH; C-terminal), but are not associated with a cognate N-acyl homoserine lactone (AHL) synthase coding gene in the same genome. Although a few LuxR solos have been characterized, their distributions as well as their role in bacterial signal perception and other processes are poorly understood. In this study we have carried out a systematic survey of distribution of all ABD containing LuxR transcriptional regulators (QS domain LuxRs) available in the InterPro database (IPR005143), and identified those lacking a cognate AHL synthase. These LuxR solos were then analyzed regarding their taxonomical distribution, predicted functions of neighboring genes and the presence of complete AHL-QS systems in the genomes that carry them. Our analyses reveal the presence of one or multiple predicted LuxR solos in many proteobacterial genomes carrying QS domain LuxRs, some of them harboring genes for one or more AHL-QS circuits. The presence of LuxR solos in bacteria occupying diverse environments suggests potential ecological functions for these proteins beyond AHL and interkingdom signaling. Based on gene context and the conservation levels of invariant amino acids of ABD, we have classified LuxR solos into functionally meaningful groups or putative orthologs. Surprisingly, putative LuxR solos were also found in a few non-proteobacterial genomes which are not known to carry AHL-QS systems. Multiple predicted LuxR solos in the same genome appeared to have different levels of conservation of invariant amino acid residues of ABD questioning their binding to AHLs. In summary, this study provides a detailed overview of distribution of LuxR solos and their probable roles in bacteria with genome sequence information.
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Affiliation(s)
- Sujatha Subramoni
- Grupo de Bioprospección, Facultad de Ingeniería, Universidad de La Sabana, Campus del Puente del Común Chía, Colombia
| | | | - Zulma R Suarez-Moreno
- Grupo de Bioprospección, Facultad de Ingeniería, Universidad de La Sabana, Campus del Puente del Común Chía, Colombia
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27
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Xu J, Zhou L, Venturi V, He YW, Kojima M, Sakakibari H, Höfte M, De Vleesschauwer D. Phytohormone-mediated interkingdom signaling shapes the outcome of rice-Xanthomonas oryzae pv. oryzae interactions. BMC PLANT BIOLOGY 2015; 15:10. [PMID: 25605284 PMCID: PMC4307914 DOI: 10.1186/s12870-014-0411-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 12/30/2014] [Indexed: 05/25/2023]
Abstract
BACKGROUND Small-molecule hormones are well known to play key roles in the plant immune signaling network that is activated upon pathogen perception. In contrast, little is known about whether phytohormones also directly influence microbial virulence, similar to what has been reported in animal systems. RESULTS In this paper, we tested the hypothesis that hormones fulfill dual roles in plant-microbe interactions by orchestrating host immune responses, on the one hand, and modulating microbial virulence traits, on the other. Employing the rice-Xanthomonas oryzae pv. oryzae (Xoo) interaction as a model system, we show that Xoo uses the classic immune hormone salicylic acid (SA) as a trigger to activate its virulence-associated quorum sensing (QS) machinery. Despite repressing swimming motility, sodium salicylate (NaSA) induced production of the Diffusible Signal Factor (DSF) and Diffusible Factor (DF) QS signals, with resultant accumulation of xanthomonadin and extracellular polysaccharides. In contrast, abscisic acid (ABA), which favors infection by Xoo, had little impact on DF- and DSF-mediated QS, but promoted bacterial swimming via the LuxR solo protein OryR. Moreover, we found both DF and DSF to influence SA- and ABA-responsive gene expression in planta. CONCLUSIONS Together our findings indicate that the rice SA and ABA signaling pathways cross-communicate with the Xoo DF and DSF QS systems and underscore the importance of bidirectional interkingdom signaling in molding plant-microbe interactions.
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Affiliation(s)
- Jing Xu
- Lab of Phytopathology, Department of Crop Protection, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
| | - Lian Zhou
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy.
| | - Ya-Wen He
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Mikiko Kojima
- RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan.
| | - Hitoshi Sakakibari
- RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan.
| | - Monica Höfte
- Lab of Phytopathology, Department of Crop Protection, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
| | - David De Vleesschauwer
- Lab of Phytopathology, Department of Crop Protection, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
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28
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Gan HM, Gan HY, Ahmad NH, Aziz NA, Hudson AO, Savka MA. Whole genome sequencing and analysis reveal insights into the genetic structure, diversity and evolutionary relatedness of luxI and luxR homologs in bacteria belonging to the Sphingomonadaceae family. Front Cell Infect Microbiol 2015; 4:188. [PMID: 25621282 PMCID: PMC4288048 DOI: 10.3389/fcimb.2014.00188] [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: 09/23/2014] [Accepted: 12/16/2014] [Indexed: 12/18/2022] Open
Abstract
Here we report the draft genomes and annotation of four N-acyl homoserine lactone (AHL)-producing members from the family Sphingomonadaceae. Comparative genomic analyses of 62 Sphingomonadaceae genomes were performed to gain insights into the distribution of the canonical luxI/R-type quorum sensing (QS) network within this family. Forty genomes contained at least one luxR homolog while the genome of Sphingobium yanoikuyae B1 contained seven Open Reading Frames (ORFs) that have significant homology to that of luxR. Thirty-three genomes contained at least one luxI homolog while the genomes of Sphingobium sp. SYK6, Sphingobium japonicum, and Sphingobium lactosutens contained four luxI. Using phylogenetic analysis, the sphingomonad LuxR homologs formed five distinct clades with two minor clades located near the plant associated bacteria (PAB) LuxR solo clade. This work for the first time shows that 13 Sphingobium and one Sphingomonas genome(s) contain three convergently oriented genes composed of two tandem luxR genes proximal to one luxI (luxR-luxR-luxI). Interestingly, luxI solos were identified in two Sphingobium species and may represent species that contribute to AHL-based QS system by contributing AHL molecules but are unable to perceive AHLs as signals. This work provides the most comprehensive description of the luxI/R circuitry and genome-based taxonomical description of the available sphingomonad genomes to date indicating that the presence of luxR solos and luxI solos are not an uncommon feature in members of the Sphingomonadaceae family.
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Affiliation(s)
- Han Ming Gan
- School of Science, Monash University Malaysia Petaling Jaya, Malaysia ; Genomics Facility, Monash University Malaysia Petaling Jaya, Malaysia
| | - Huan You Gan
- School of Science, Monash University Malaysia Petaling Jaya, Malaysia ; Genomics Facility, Monash University Malaysia Petaling Jaya, Malaysia
| | - Nurul H Ahmad
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester NY, USA
| | - Nazrin A Aziz
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester NY, USA
| | - André O Hudson
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester NY, USA
| | - Michael A Savka
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester NY, USA
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29
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Yaryura PM, Conforte VP, Malamud F, Roeschlin R, de Pino V, Castagnaro AP, McCarthy Y, Dow JM, Marano MR, Vojnov AA. XbmR, a new transcription factor involved in the regulation of chemotaxis, biofilm formation and virulence in Xanthomonas citri subsp. citri. Environ Microbiol 2014; 17:4164-76. [PMID: 25346091 DOI: 10.1111/1462-2920.12684] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 10/19/2014] [Indexed: 12/22/2022]
Abstract
Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus canker. Biofilm formation on citrus leaves plays an important role in epiphytic survival of Xcc. Biofilm formation is affected by transposon insertion in XAC3733, which encodes a transcriptional activator of the NtrC family, not linked to a gene encoding a sensor protein, thus could be considered as an 'orphan' regulator whose function is poorly understood in Xanthomonas spp. Here we show that mutation of XAC3733 (named xbmR) resulted in impaired structural development of the Xcc biofilm, loss of chemotaxis and reduced virulence in grapefruit plants. All defective phenotypes were restored to wild-type levels by the introduction of PA2567 from Pseudomonas aeruginosa, which encodes a phosphodiesterase active in the degradation of cyclic diguanosine monophosphate (c-di-GMP). A knockout of xbmR led to a substantial downregulation of fliA that encodes a σ(28) transcription factor, as well as fliC and XAC0350 which are potential member of the σ(28) regulon. XAC0350 encodes an HD-GYP domain c-di-GMP phosphodiesterase. These findings suggest that XbmR is a key regulator of flagellar-dependent motility and chemotaxis exerting its action through a regulatory pathway that involves FliA and c-di-GMP.
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Affiliation(s)
- Pablo M Yaryura
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Valeria P Conforte
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Florencia Malamud
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Roxana Roeschlin
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET). Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, S2000FHN, Rosario, Argentina
| | - Verónica de Pino
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Atilio P Castagnaro
- Estación Experimental Agroindustrial Obispo Colombres, Av. William Cross, 3150, Las Talitas, Tucumán, Argentina
| | - Yvonne McCarthy
- School of Microbiology, University College Cork, Cork, Ireland
| | - J Maxwell Dow
- School of Microbiology, University College Cork, Cork, Ireland
| | - María R Marano
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET). Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, S2000FHN, Rosario, Argentina
| | - Adrián A Vojnov
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
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30
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Patel HK, Ferrante P, Covaceuszach S, Lamba D, Scortichini M, Venturi V. The kiwifruit emerging pathogen Pseudomonas syringae pv. actinidiae does not produce AHLs but possesses three luxR solos. PLoS One 2014; 9:e87862. [PMID: 24498215 PMCID: PMC3909224 DOI: 10.1371/journal.pone.0087862] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/30/2013] [Indexed: 12/30/2022] Open
Abstract
Pseudomonas syringae pv. actinidiae (Psa) is an emerging phytopathogen causing bacterial canker disease in kiwifruit plants worldwide. Quorum sensing (QS) gene regulation plays important roles in many different bacterial plant pathogens. In this study we analyzed the presence and possible role of N-acyl homoserine lactone (AHL) quorum sensing in Psa. It was established that Psa does not produce AHLs and that a typical complete LuxI/R QS system is absent in Psa strains. Psa however possesses three putative luxR solos designated here as PsaR1, PsaR2 and PsaR3. PsaR2 belongs to the sub-family of LuxR solos present in many plant associated bacteria (PAB) that binds and responds to yet unknown plant signal molecules. PsaR1 and PsaR3 are highly similar to LuxRs which bind AHLs and are part of the canonical LuxI/R AHL QS systems. Mutation in all the three luxR solos of Psa showed reduction of in planta survival and also showed additive effect if more than one solo was inactivated in double mutants. Gene promoter analysis revealed that the three solos are not auto-regulated and investigated their possible role in several bacterial phenotypes.
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Affiliation(s)
| | - Patrizia Ferrante
- Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy
| | - Sonia Covaceuszach
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, U.O.S di Trieste, Trieste, Italy
| | - Doriano Lamba
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, U.O.S di Trieste, Trieste, Italy
| | - Marco Scortichini
- Research Centre for Fruit Crops, Agricultural Research Council, Roma, Italy
- Research Unit for Fruit Trees, Agricultural Research Council, Caserta, Italy
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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31
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Dudnik A, Dudler R. Genomics-Based Exploration of Virulence Determinants and Host-Specific Adaptations of Pseudomonas syringae Strains Isolated from Grasses. Pathogens 2014; 3:121-48. [PMID: 25437611 PMCID: PMC4235733 DOI: 10.3390/pathogens3010121] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/20/2014] [Accepted: 01/22/2014] [Indexed: 12/14/2022] Open
Abstract
The Pseudomonas syringae species complex has recently been named the number one plant pathogen, due to its economic and environmental impacts, as well as for its role in scientific research. The bacterium has been repeatedly reported to cause outbreaks on bean, cucumber, stone fruit, kiwi and olive tree, as well as on other crop and non-crop plants. It also serves as a model organism for research on the Type III secretion system (T3SS) and plant-pathogen interactions. While most of the current work on this pathogen is either carried out on one of three model strains found on dicot plants with completely sequenced genomes or on isolates obtained from recent outbreaks, not much is known about strains isolated from grasses (Poaceae). Here, we use comparative genomics in order to identify putative virulence-associated genes and other Poaceae-specific adaptations in several newly available genome sequences of strains isolated from grass species. All strains possess only a small number of known Type III effectors, therefore pointing to the importance of non-Type III secreted virulence factors. The implications of this finding are discussed.
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Affiliation(s)
- Alexey Dudnik
- Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
| | - Robert Dudler
- Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
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Patel HK, Suárez-Moreno ZR, Degrassi G, Subramoni S, González JF, Venturi V. Bacterial LuxR solos have evolved to respond to different molecules including signals from plants. FRONTIERS IN PLANT SCIENCE 2013; 4:447. [PMID: 24273546 DOI: 10.3389/fpls.2013.00447.03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 10/19/2013] [Indexed: 05/26/2023]
Abstract
A future challenge will be understanding the extensive communication that most likely takes place in bacterial interspecies and interkingdom signaling between plants and bacteria. A major bacterial inter-cellular signaling system in Gram-negative bacteria is LuxI/R quorum sensing (QS) based on the production (via the LuxI-family proteins) and detection (via the LuxR-family proteins) of N-acyl homoserine lactones (AHLs) signaling molecules. LuxR proteins which have the same modular structure of QS LuxRs but are devoid of a cognate LuxI AHL synthase are called solos. LuxR solos have been shown to be responsible to respond to exogenous AHLs produced by neighboring cells as well endogenously produced AHLs. It is now also evident that some LuxR proteins have evolved from the ability to binding AHLs and respond to other molecules/signals. For example, recent research has shown that a sub-family of LuxR solos responds to small molecules produced by plants. This indicates the presence of a uni-directional interkingdom signaling system occurring from plants to bacteria. In addition LuxR solos have now been also implicated to respond to endogenously produced signals which are not AHLs. In this Mini Review article we will discuss current trends and implications of the role of LuxR solos in bacterial responses to other signals using proteins related to AHL QS systems.
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Affiliation(s)
- Hitendra K Patel
- International Centre for Genetic Engineering and Biotechnology Trieste, Italy
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Patel HK, Suárez-Moreno ZR, Degrassi G, Subramoni S, González JF, Venturi V. Bacterial LuxR solos have evolved to respond to different molecules including signals from plants. FRONTIERS IN PLANT SCIENCE 2013; 4:447. [PMID: 24273546 PMCID: PMC3824090 DOI: 10.3389/fpls.2013.00447] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 10/19/2013] [Indexed: 05/08/2023]
Abstract
A future challenge will be understanding the extensive communication that most likely takes place in bacterial interspecies and interkingdom signaling between plants and bacteria. A major bacterial inter-cellular signaling system in Gram-negative bacteria is LuxI/R quorum sensing (QS) based on the production (via the LuxI-family proteins) and detection (via the LuxR-family proteins) of N-acyl homoserine lactones (AHLs) signaling molecules. LuxR proteins which have the same modular structure of QS LuxRs but are devoid of a cognate LuxI AHL synthase are called solos. LuxR solos have been shown to be responsible to respond to exogenous AHLs produced by neighboring cells as well endogenously produced AHLs. It is now also evident that some LuxR proteins have evolved from the ability to binding AHLs and respond to other molecules/signals. For example, recent research has shown that a sub-family of LuxR solos responds to small molecules produced by plants. This indicates the presence of a uni-directional interkingdom signaling system occurring from plants to bacteria. In addition LuxR solos have now been also implicated to respond to endogenously produced signals which are not AHLs. In this Mini Review article we will discuss current trends and implications of the role of LuxR solos in bacterial responses to other signals using proteins related to AHL QS systems.
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Affiliation(s)
| | | | | | | | | | - Vittorio Venturi
- *Correspondence: Vittorio Venturi, International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy e-mail:
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Venturi V, Fuqua C. Chemical signaling between plants and plant-pathogenic bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 2013; 51:17-37. [PMID: 23915131 DOI: 10.1146/annurev-phyto-082712-102239] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Studies of chemical signaling between plants and bacteria in the past have been largely confined to two models: the rhizobial-legume symbiotic association and pathogenesis between agrobacteria and their host plants. Recent studies are beginning to provide evidence that many plant-associated bacteria undergo chemical signaling with the plant host via low-molecular-weight compounds. Plant-produced compounds interact with bacterial regulatory proteins that then affect gene expression. Similarly, bacterial quorum-sensing signals result in a range of functional responses in plants. This review attempts to highlight current knowledge in chemical signaling that takes place between pathogenic bacteria and plants. This chemical communication between plant and bacteria, also referred to as interkingdom signaling, will likely become a major research field in the future, as it allows the design of specific strategies to create plants that are resistant to plant pathogens.
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Affiliation(s)
- Vittorio Venturi
- International Center for Genetic Engineering and Biotechnology, 34149 Trieste, Italy.
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