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Alexandrino AV, Prieto EL, Nicolela NCS, da Silva Marin TG, Dos Santos TA, de Oliveira da Silva JPM, da Cunha AF, Behlau F, Novo-Mansur MTM. Xylose Isomerase Depletion Enhances Virulence of Xanthomonas citri subsp. citri in Citrus aurantifolia. Int J Mol Sci 2023; 24:11491. [PMID: 37511250 PMCID: PMC10380989 DOI: 10.3390/ijms241411491] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 04/14/2023] [Accepted: 04/17/2023] [Indexed: 07/30/2023] Open
Abstract
Citrus canker, caused by the bacterium Xanthomonas citri (Xcc), is one of the most devastating diseases for the citrus industry. Xylose is a constituent of the cell wall of plants, and the ability of Xcc to use this carbohydrate may play a role in virulence. Xcc has two genes codifying for xylose isomerase (XI), a bifunctional enzyme that interconverts D-xylose into D-xylulose and D-glucose into D-fructose. The aim of this work was to investigate the functional role of the two putative XI ORFs, XAC1776 (xylA1) and XAC4225 (xylA2), in Xcc pathogenicity. XI-coding genes of Xcc were deleted, and the single mutants (XccΔxylA1 or XccΔxylA2) or the double mutant (XccΔxylA1ΔxylA2) remained viable. The deletion of one or both XI genes (xylA1 and/or xylA2) increased the aggressiveness of the mutants, causing disease symptoms. RT-qPCR analysis of wild strain and xylA deletion mutants grown in vivo and in vitro revealed that the highest expression level of hrpX and xylR was observed in vivo for the double mutant. The results indicate that XI depletion increases the expression of the hrp regulatory genes in Xcc. We concluded that the intracellular accumulation of xylose enhances Xcc virulence.
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Affiliation(s)
- André Vessoni Alexandrino
- Laboratório de Bioquímica e Biologia Molecular Aplicada-LBBMA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
- Programa de Pós-Graduação em Biotecnologia-PPGBiotec, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
| | - Evandro Luis Prieto
- Laboratório de Bioquímica e Biologia Molecular Aplicada-LBBMA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
- Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular-PPGGEv, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
| | - Nicole Castro Silva Nicolela
- Laboratório de Bioquímica e Biologia Molecular Aplicada-LBBMA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
| | | | | | - João Pedro Maia de Oliveira da Silva
- Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular-PPGGEv, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
- Laboratório de Bioquímica e Genética Aplicada-LBGA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
| | - Anderson Ferreira da Cunha
- Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular-PPGGEv, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
- Laboratório de Bioquímica e Genética Aplicada-LBGA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
| | - Franklin Behlau
- Fundo de Defesa da Citricultura-Fundecitrus, Araraquara 14807-040, SP, Brazil
| | - Maria Teresa Marques Novo-Mansur
- Laboratório de Bioquímica e Biologia Molecular Aplicada-LBBMA, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
- Programa de Pós-Graduação em Biotecnologia-PPGBiotec, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
- Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular-PPGGEv, Universidade Federal de São Carlos, São Carlos 13565-905, SP, Brazil
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Murillo-Roos M, Abdullah HSM, Debbar M, Ueberschaar N, Agler MT. Cross-feeding niches among commensal leaf bacteria are shaped by the interaction of strain-level diversity and resource availability. THE ISME JOURNAL 2022; 16:2280-2289. [PMID: 35768644 PMCID: PMC9381498 DOI: 10.1038/s41396-022-01271-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 05/20/2022] [Accepted: 06/10/2022] [Indexed: 12/27/2022]
Abstract
Leaf microbiomes play crucial roles in plant health, making it important to understand the origins and functional relevance of their diversity. High strain-level leaf bacterial genetic diversity is known to be relevant for interactions with hosts, but little is known about its relevance for interactions with the multitude of diverse co-colonizing microorganisms. In leaves, nutrients like amino acids are major regulators of microbial growth and activity. Using metabolomics of leaf apoplast fluid, we found that different species of the plant genus Flaveria considerably differ in the concentrations of high-cost amino acids. We investigated how these differences affect bacterial community diversity and assembly by enriching leaf bacteria in vitro with only sucrose or sucrose + amino acids as possible carbon sources. Enrichments from F. robusta were dominated by Pantoea sp. and Pseudomonas sp., regardless of carbon source. The latter was unable to grow on sucrose alone but persisted in the sucrose-only enrichment thanks to exchange of diverse metabolites from Pantoea sp. Individual Pseudomonas strains in the enrichments had high genetic similarity but still displayed clear niche partitioning, enabling distinct strains to cross-feed in parallel. Pantoea strains were also closely related, but individuals enriched from F. trinervia fed Pseudomonas more poorly than those from F. robusta. This can be explained in part by the plant environment, since some cross-feeding interactions were selected for, when experimentally evolved in a poor (sucrose-only) environment but selected against in a rich (sucrose + amino acids) one. Together, our work shows that leaf bacterial diversity is functionally relevant in cross-feeding interactions and strongly suggests that the leaf resource environment can shape these interactions and thereby indirectly drive bacterial diversity.
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Affiliation(s)
- Mariana Murillo-Roos
- Plant Microbiosis Lab, Department of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Hafiz Syed M Abdullah
- Plant Microbiosis Lab, Department of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Mossaab Debbar
- Plant Microbiosis Lab, Department of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Nico Ueberschaar
- Mass Spectrometry Platform, Friedrich Schiller University Jena, Jena, Germany
| | - Matthew T Agler
- Plant Microbiosis Lab, Department of Microbiology, Friedrich Schiller University Jena, Jena, Germany.
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Vieira PS, Bonfim IM, Araujo EA, Melo RR, Lima AR, Fessel MR, Paixão DAA, Persinoti GF, Rocco SA, Lima TB, Pirolla RAS, Morais MAB, Correa JBL, Zanphorlin LM, Diogo JA, Lima EA, Grandis A, Buckeridge MS, Gozzo FC, Benedetti CE, Polikarpov I, Giuseppe PO, Murakami MT. Xyloglucan processing machinery in Xanthomonas pathogens and its role in the transcriptional activation of virulence factors. Nat Commun 2021; 12:4049. [PMID: 34193873 PMCID: PMC8245568 DOI: 10.1038/s41467-021-24277-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/07/2021] [Indexed: 02/06/2023] Open
Abstract
Xyloglucans are highly substituted and recalcitrant polysaccharides found in the primary cell walls of vascular plants, acting as a barrier against pathogens. Here, we reveal that the diverse and economically relevant Xanthomonas bacteria are endowed with a xyloglucan depolymerization machinery that is linked to pathogenesis. Using the citrus canker pathogen as a model organism, we show that this system encompasses distinctive glycoside hydrolases, a modular xyloglucan acetylesterase and specific membrane transporters, demonstrating that plant-associated bacteria employ distinct molecular strategies from commensal gut bacteria to cope with xyloglucans. Notably, the sugars released by this system elicit the expression of several key virulence factors, including the type III secretion system, a membrane-embedded apparatus to deliver effector proteins into the host cells. Together, these findings shed light on the molecular mechanisms underpinning the intricate enzymatic machinery of Xanthomonas to depolymerize xyloglucans and uncover a role for this system in signaling pathways driving pathogenesis.
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Affiliation(s)
- Plinio S. Vieira
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Isabela M. Bonfim
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil ,grid.411087.b0000 0001 0723 2494Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, São Paulo Brazil
| | - Evandro A. Araujo
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil ,grid.452567.70000 0004 0445 0877Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Ricardo R. Melo
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Augusto R. Lima
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Melissa R. Fessel
- grid.418514.d0000 0001 1702 8585Butantan Institute, Butantan Foundation, São Paulo, São Paulo Brazil
| | - Douglas A. A. Paixão
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Gabriela F. Persinoti
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Silvana A. Rocco
- grid.452567.70000 0004 0445 0877Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Tatiani B. Lima
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Renan A. S. Pirolla
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Mariana A. B. Morais
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Jessica B. L. Correa
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Leticia M. Zanphorlin
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Jose A. Diogo
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil ,grid.411087.b0000 0001 0723 2494Graduate Program in Functional and Molecular Biology, Institute of Biology, University of Campinas, Campinas, São Paulo Brazil
| | - Evandro A. Lima
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Adriana Grandis
- grid.11899.380000 0004 1937 0722Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Marcos S. Buckeridge
- grid.11899.380000 0004 1937 0722Department of Botany, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Fabio C. Gozzo
- grid.411087.b0000 0001 0723 2494Institute of Chemistry, University of Campinas, Campinas, São Paulo Brazil
| | - Celso E. Benedetti
- grid.452567.70000 0004 0445 0877Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Igor Polikarpov
- grid.11899.380000 0004 1937 0722São Carlos Institute of Physics, University of São Paulo, São Carlos, São Paulo Brazil
| | - Priscila O. Giuseppe
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
| | - Mario T. Murakami
- grid.452567.70000 0004 0445 0877Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, São Paulo Brazil
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The HrpG/HrpX Regulon of Xanthomonads-An Insight to the Complexity of Regulation of Virulence Traits in Phytopathogenic Bacteria. Microorganisms 2021; 9:microorganisms9010187. [PMID: 33467109 PMCID: PMC7831014 DOI: 10.3390/microorganisms9010187] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/05/2022] Open
Abstract
Bacteria of the genus Xanthomonas cause a wide variety of economically important diseases in most crops. The virulence of the majority of Xanthomonas spp. is dependent on secretion and translocation of effectors by the type 3 secretion system (T3SS) that is controlled by two master transcriptional regulators HrpG and HrpX. Since their discovery in the 1990s, the two regulators were the focal point of many studies aiming to decipher the regulatory network that controls pathogenicity in Xanthomonas bacteria. HrpG controls the expression of HrpX, which subsequently controls the expression of T3SS apparatus genes and effectors. The HrpG/HrpX regulon is activated in planta and subjected to tight metabolic and genetic regulation. In this review, we cover the advances made in understanding the regulatory networks that control and are controlled by the HrpG/HrpX regulon and their conservation between different Xanthomonas spp.
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Xiao CL, Xie SQ, Xie QB, Liu ZY, Xing JF, Ji KK, Tao J, Dai LY, Luo F. N6-Methyladenine DNA modification in Xanthomonas oryzae pv. oryzicola genome. Sci Rep 2018; 8:16272. [PMID: 30389999 PMCID: PMC6215013 DOI: 10.1038/s41598-018-34559-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/19/2018] [Indexed: 12/20/2022] Open
Abstract
DNA N6-methyladenine (6mA) modifications expand the information capacity of DNA and have long been known to exist in bacterial genomes. Xanthomonas oryzae pv. Oryzicola (Xoc) is the causative agent of bacterial leaf streak, an emerging and destructive disease in rice worldwide. However, the genome-wide distribution patterns and potential functions of 6mA in Xoc are largely unknown. In this study, we analyzed the levels and global distribution patterns of 6mA modification in genomic DNA of seven Xoc strains (BLS256, BLS279, CFBP2286, CFBP7331, CFBP7341, L8 and RS105). The 6mA modification was found to be widely distributed across the seven Xoc genomes, accounting for percent of 3.80, 3.10, 3.70, 4.20, 3.40, 2.10, and 3.10 of the total adenines in BLS256, BLS279, CFBP2286, CFBP7331, CFBP7341, L8, and RS105, respectively. Notably, more than 82% of 6mA sites were located within gene bodies in all seven strains. Two specific motifs for 6 mA modification, ARGT and AVCG, were prevalent in all seven strains. Comparison of putative DNA methylation motifs from the seven strains reveals that Xoc have a specific DNA methylation system. Furthermore, the 6 mA modification of rpfC dramatically decreased during Xoc infection indicates the important role for Xoc adaption to environment.
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Affiliation(s)
- Chuan-Le Xiao
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Plant Protection, Hunan Agricultural University, Changsha, China
| | - Shang-Qian Xie
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, 570228, China
| | - Qing-Biao Xie
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, 570228, China
| | - Zhao-Yu Liu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, 570228, China
| | - Jian-Feng Xing
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, 570228, China
| | - Kai-Kai Ji
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, 570228, China
| | - Jun Tao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, 570228, China.
| | - Liang-Ying Dai
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Plant Protection, Hunan Agricultural University, Changsha, China.
| | - Feng Luo
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Plant Protection, Hunan Agricultural University, Changsha, China. .,School of Computing, Clemson University, Clemson, 29634-0974, USA.
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Hu Y, Zhang L, Wang X, Sun F, Kong X, Dong H, Xu H. Two virulent sRNAs identified by genomic sequencing target the type III secretion system in rice bacterial blight pathogen. BMC PLANT BIOLOGY 2018; 18:237. [PMID: 30326834 PMCID: PMC6192180 DOI: 10.1186/s12870-018-1470-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 10/05/2018] [Indexed: 05/23/2023]
Abstract
BACKGROUND Small non-coding RNA (sRNA) short sequences regulate various biological processes in all organisms, including bacteria that are animal or plant pathogens. Virulent or pathogenicity-associated sRNAs have been increasingly elucidated in animal pathogens but little is known about similar category of sRNAs in plant-pathogenic bacteria. This is particularly true regarding rice bacterial blight pathogen Xanthomonas oryzae pathovar oryzae (Xoo) as studies on the virulent role of Xoo sRNAs is very limited at present. RESULTS The number and genomic distribution of sRNAs in Xoo were determined by bioinformatics analysis based on high throughput sequencing (sRNA-Seq) of the bacterial cultures from virulence-inducing and standard growth media, respectively. A total of 601 sRNAs were identified in the Xoo genome and ten virulent sRNA candidates were screened out based on significant differences of their expression levels between the culture conditions. In addition, trans3287 and trans3288 were also selected as candidates due to high expression levels in both media. The differential expression of 12 sRNAs evidenced by the sRNA-Seq data was confirmed by a convincing quantitative method. Based on genetic analysis of Xoo ΔsRNA mutants generated by deletion of the 12 single sRNAs, trans217 and trans3287 were characterized as virulent sRNAs. They are essential not only for the formation of bacterial blight in a susceptible rice variety Nipponbare but also for the induction of hypersensitive response (HR) in nonhost plant tobacco. Xoo Δtrans217 and Δtrans3287 mutants fail to induce bacterial blight in Nipponbare and also fail to induce the HR in tobacco, whereas, genetic complementation restores both mutants to the wild type in the virulent performance and HR induction. Similar effects of gene knockout and complementation were found in the expression of hrpG and hrpX genes, which encode regulatory proteins of the type III secretion system. Consistently, secretion of a type III effector, PthXo1, is blocked in Δtrans217 or Δtrans3287 bacterial cultures but retrieved by genetic complementation to both mutants. CONCLUSIONS The genetic analysis characterizes trans217 and trans3287 as pathogenicity-associated sRNAs essential for the bacterial virulence on the susceptible rice variety and for the HR elicitation in the nonhost plant. The molecular evidence suggests that both virulent sRNAs regulate the bacterial virulence by targeting the type III secretion system.
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Affiliation(s)
- Yiqun Hu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu Province China
| | - Liyuan Zhang
- State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing, 210095 Jiangsu Province China
| | - Xuan Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu Province China
| | - Fengli Sun
- State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing, 210095 Jiangsu Province China
- Current Address: Rural Work Bureau of Zhangpu Town, Suzhou, 215300 Jiangsu Province China
| | - Xiangxin Kong
- State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing, 210095 Jiangsu Province China
| | - Hansong Dong
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095 Jiangsu Province China
| | - Heng Xu
- State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing, 210095 Jiangsu Province China
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Ikawa Y, Ohnishi S, Shoji A, Furutani A, Tsuge S. Concomitant Regulation by a LacI-Type Transcriptional Repressor XylR on Genes Involved in Xylan and Xylose Metabolism and the Type III Secretion System in Rice Pathogen Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:605-613. [PMID: 29360015 DOI: 10.1094/mpmi-11-17-0277-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The hypersensitive response and pathogenicity (hrp) genes of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, encode components of the type III secretion system and are essential for virulence. Expression of hrp genes is regulated by two key hrp regulators, HrpG and HrpX; HrpG regulates hrpX and hrpA, and HrpX regulates the other hrp genes on hrpB-hrpF operons. We previously reported the sugar-dependent quantitative regulation of HrpX; the regulator highly accumulates in the presence of xylose, followed by high hrp gene expression. Here, we found that, in a mutant lacking the LacI-type transcriptional regulator XylR, HrpX accumulation and hrp gene expression were high even in the medium without xylose, reaching the similar levels present in the wild type incubated in the xylose-containing medium. XylR also negatively regulated one of two xylose isomerase genes (xylA2 but not xylA1) by binding to the motif sequence in the upstream region of the gene. Xylose isomerase is an essential enzyme in xylose metabolism and interconverts between xylose and xylulose. Our results suggest that, in the presence of xylose, inactivation of XylR leads to greater xylan and xylose utilization and, simultaneously, to higher accumulation of HrpX, followed by higher hrp gene expression in the bacterium.
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Affiliation(s)
- Yumi Ikawa
- 1 Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; and
| | - Sayaka Ohnishi
- 1 Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; and
| | - Akiko Shoji
- 1 Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; and
| | - Ayako Furutani
- 2 Gene Research Center, Ibaraki University, Inashiki 300-0393, Japan
| | - Seiji Tsuge
- 1 Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan; and
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Pan Y, Liang F, Li RJ, Qian W. MarR-Family Transcription Factor HpaR Controls Expression of the vgrR-vgrS Operon of Xanthomonas campestris pv. campestris. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:299-310. [PMID: 29077520 DOI: 10.1094/mpmi-07-17-0187-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
MarR (multiple antibiotic resistance regulator)-family transcription factors (TFs), which regulate the expression of virulence factors and other physiological pathways in pathogenic bacteria, are regarded as ideal molecular targets for the development of novel antimicrobial strategies. In the plant bacterial pathogen Xanthomonas campestris pv. campestris, HpaR, a typical MarR-family TF, is associated with bacterial virulence, but its mechanism of virulence regulation remains unclear. Here, we dissected the HpaR regulon using high-throughput RNA sequencing and chromatin immunoprecipitation sequencing. HpaR directly or indirectly controls the expression of approximately 448 genes; it acts both as a transcriptional activator and a repressor to control the expression of downstream genes by directly binding to their promoter regions. The consensus HpaR-binding DNA motifs contain imperfect palindromic sequences similar to [G/T]CAACAATT[C/T]TTG. In-depth analysis revealed that HpaR positively modulates transcription level of the vgrR-vgrS operon that encodes an important two-component signal transduction system to sense iron depletion and regulate bacterial virulence. Epistasis analysis demonstrated that vgrR-vgrS is a core downstream component of HpaR regulation, as overexpression of vgrR restored the phenotypic deficiencies caused by a hpaR mutation. This dissection of the HpaR regulon should facilitate future studies focused on the activating mechanism of HpaR during bacterial infection.
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Affiliation(s)
- Yue Pan
- 1 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- 2 School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; and
| | - Fang Liang
- 3 Beijing Institute of Genomics, Chinese Academy of Sciences
| | - Ru-Jiao Li
- 3 Beijing Institute of Genomics, Chinese Academy of Sciences
| | - Wei Qian
- 1 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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9
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Maximiano MR, Oliveira-Neto OB, Franco OL, Mehta A. Validation of an in vitro system for studies of pathogenicity mechanisms in Xanthomonas campestris. FEMS Microbiol Lett 2017; 364:4494362. [PMID: 29040467 DOI: 10.1093/femsle/fnx217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 10/11/2017] [Indexed: 01/16/2023] Open
Abstract
Several minimal media capable of inducing pathogenicity genes have been used to study plant-pathogen interactions. An in planta assay to study a closer interaction between the bacteria and the host was also developed and has been employed by our group. In order to determine whether growth medium could be improved to better approximate in planta conditions beyond that offered by the defined minimal medium XVM1, we compared the expression of 20 Xanthomonas campestris pv. campestris (Xcc) genes by quantitative reverse transcription - polymerase chain reaction (qRT-PCR) under in vivo (bacteria recovered from the plant) and in vitro (rich medium NYG, minimal medium XVM1 and XVM1 + leaf extract) growth systems. The results showed a higher expression level of the genes in the in planta system when compared to growth in culture media. In planta growth is closest to a real interaction condition and captures the complexity of the plant cell environment; however, this system has some limitations. The main finding of our work is that the addition of plant extract to XVM1 medium results in a gene expression profile that better matches the in planta profile, when compared with the XVM1 medium alone, giving support to the use of plant extract to study pathogenicity mechanisms in Xanthomonas.
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Affiliation(s)
- Mariana Rocha Maximiano
- Embrapa Recursos Genéticos e Biotecnologia, PBI, Av. W/5 Norte Final, Brasília, Distrito Federal 70770-917, Brazil.,Programa de Pós-Graduação em Ciências Biológicas (Imunologia e DIP/Genética e Biotecnologia), Universidade Federal de Juiz de Fora, Rua José Lourenço Kelmer, S/n - Martelos, Juiz de Fora, Minas Gerais, 36036-330, Brazil
| | - Osmundo B Oliveira-Neto
- Embrapa Recursos Genéticos e Biotecnologia, PBI, Av. W/5 Norte Final, Brasília, Distrito Federal 70770-917, Brazil
| | - Octávio L Franco
- Programa de Pós-Graduação em Ciências Biológicas (Imunologia e DIP/Genética e Biotecnologia), Universidade Federal de Juiz de Fora, Rua José Lourenço Kelmer, S/n - Martelos, Juiz de Fora, Minas Gerais, 36036-330, Brazil.,S-Inova Biotech, Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Av. Tamandaré, 6000, Campo Grande, Mato Grosso do Sul, 79117-900, Brazil.,Centro de Analises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, SGAN 916N, Modulo C, Sala 219, Brasília, Distrito Federal 70790-100, Brazil
| | - Angela Mehta
- Embrapa Recursos Genéticos e Biotecnologia, PBI, Av. W/5 Norte Final, Brasília, Distrito Federal 70770-917, Brazil
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10
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GamR, the LysR-Type Galactose Metabolism Regulator, Regulates hrp Gene Expression via Transcriptional Activation of Two Key hrp Regulators, HrpG and HrpX, in Xanthomonas oryzae pv. oryzae. Appl Environ Microbiol 2016; 82:3947-3958. [PMID: 27107122 DOI: 10.1128/aem.00513-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/18/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight of rice. For the virulence of the bacterium, the hrp genes, encoding components of the type III secretion system, are indispensable. The expression of hrp genes is regulated by two key hrp regulators, HrpG and HrpX: HrpG regulates hrpX, and HrpX regulates other hrp genes. Several other regulators have been shown to be involved in the regulation of hrp genes. Here, we found that a LysR-type transcriptional regulator that we named GamR, encoded by XOO_2767 of X. oryzae pv. oryzae strain MAFF311018, positively regulated the transcription of both hrpG and hrpX, which are adjacent to each other but have opposite orientations, with an intergenic upstream region in common. In a gel electrophoresis mobility shift assay, GamR bound directly to the middle of the upstream region common to hrpG and hrpX The loss of either GamR or its binding sites decreased hrpG and hrpX expression. Also, GamR bound to the upstream region of either a galactose metabolism-related gene (XOO_2768) or a galactose metabolism-related operon (XOO_2768 to XOO_2771) located next to gamR itself and positively regulated the genes. The deletion of the regulator gene resulted in less bacterial growth in a synthetic medium with galactose as a sole sugar source. Interestingly, induction of the galactose metabolism-related gene was dependent on galactose, while that of the hrp regulator genes was galactose independent. Our results indicate that the LysR-type transcriptional regulator that regulates the galactose metabolism-related gene(s) also acts in positive regulation of two key hrp regulators and the following hrp genes in X. oryzae pv. oryzae. IMPORTANCE The expression of hrp genes encoding components of the type III secretion system is essential for the virulence of many plant-pathogenic bacteria, including Xanthomonas oryzae pv. oryzae. It is specifically induced during infection. Research has revealed that in this bacterium, hrp gene expression is controlled by two key hrp regulators, HrpG and HrpX, along with several other regulators in the complex regulatory network, but the details remain unclear. Here, we found that a novel LysR-type transcriptional activator, named GamR, functions as an hrp regulator by directly activating the transcription of both hrpG and hrpX Interestingly, GamR also regulates a galactose metabolism-related gene (or operon) in a galactose-dependent manner, while the regulation of hrpG and hrpX is independent of the sugar. Our finding of a novel hrp regulator that directly and simultaneously regulates two key hrp regulators provides new insights into an important and complex regulation system of X. oryzae pv. oryzae hrp genes.
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