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Geng H, Su R, Tao Y, Huang W, Zhou Z, Zhou H, Su Q, Liu X, Ji Z, Guo W. RpoE Orchestrates Oxidative Stress Adaptation, Virulence, and Dual Plant Immune Modulation in Xanthomonas axonopodis pv. glycines. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2025; 73:10826-10839. [PMID: 40294209 DOI: 10.1021/acs.jafc.5c00235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2025]
Abstract
In Xanthomonas axonopodis pv. glycines (Xag), rpoE (encoding σE) resided within the conserved rseA-mucD operon but was dually repressed by DSF signaling and the global regulator Clp. Although H2O2 induced rpoE transcription, its expression was paradoxically downregulated by H2O2-detoxification genes (oxyR, ahpC, ahpF, catB), suggesting a potential feedback loop. Notably, the rpoE mutant exhibited attenuated soybean virulence characterized by (1) reduced cell wall-degrading enzymes (CWDEs) production, leading to diminished activation of soybean innate immunity (ROS burst, callose deposition, programmed cell death, and jasmonic acid accumulation); (2) increased H2O2 sensitivity with impaired siderophore-mediated iron acquisition; (3) failure to elicit hypersensitive response (HR) in nonhosts. Significantly, rpoE complementation fully restored virulence traits. Collectively, RpoE emerges as a central regulator orchestrating oxidative stress adaptation, stealth pathogenesis via CWDEs-mediated immune suppression, and host-specific virulence/HR elicitation in Xag through its unique network, redefining sigma factor functionality in xanthomonads and providing targets for disrupting pathogen-host interactions.
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Affiliation(s)
- Huiya Geng
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Ruyi Su
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Yifei Tao
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Wenyao Huang
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Zihan Zhou
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Houyu Zhou
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Qian Su
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Xia Liu
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Zhiyuan Ji
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wei Guo
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
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Han SW, Lee MA, Yoo Y, Cho MH, Lee SW. Genome-wide Screening to Identify Responsive Regulators Involved in the Virulence of Xanthomonas oryzae pv. oryzae. THE PLANT PATHOLOGY JOURNAL 2019; 35:84-89. [PMID: 30828283 PMCID: PMC6385649 DOI: 10.5423/ppj.nt.09.2018.0193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 06/09/2023]
Abstract
Two-component systems (TCSs) are critical to the pathogenesis of Xanthomonas oryzae pv. oryzae (Xoo). We mutated 55 of 62 genes annotated as responsive regulators (RRs) of TCSs in the genome of Xoo strain PXO99A and identified 9 genes involved in Xoo virulence. Four (rpfG, hrpG, stoS, and detR) of the 9 genes were previously reported as key regulators of Xoo virulence and the other 5 have not been characterized. Lesion lengths on rice leaves inoculated with the mutants were shorter than those of the wild type and were significantly restored with gene complementation. The population density of the 5 mutants in planta was smaller than that of PXO99A at 14 days after inoculation, but the growth curves of the mutants in rich medium were similar to those of the wild type. These newly reported RR genes will facilitate studies on the function of TCSs and of the integrated regulation of TCSs for Xoo pathogenesis.
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Affiliation(s)
- Sang-Wook Han
- Department of Integrative Plant Science, Chung-Ang University, Anseong 17546,
Korea
| | - Mi-Ae Lee
- Graduate School of Biotechnology, Kyung Hee University, Yongin 17104,
Korea
- Crop Biotech Institute, Kyung Hee University, Yongin 17104,
Korea
| | - Youngchul Yoo
- Graduate School of Biotechnology, Kyung Hee University, Yongin 17104,
Korea
- Crop Biotech Institute, Kyung Hee University, Yongin 17104,
Korea
| | - Man-Ho Cho
- Graduate School of Biotechnology, Kyung Hee University, Yongin 17104,
Korea
| | - Sang-Won Lee
- Graduate School of Biotechnology, Kyung Hee University, Yongin 17104,
Korea
- Crop Biotech Institute, Kyung Hee University, Yongin 17104,
Korea
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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: 0.4] [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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Wang J, Guo J, Wang S, Zeng Z, Zheng D, Yao X, Yu H, Ruan L. The global strategy employed by Xanthomonas oryzae pv. oryzae to conquer low-oxygen tension. J Proteomics 2017; 161:68-77. [PMID: 28412528 DOI: 10.1016/j.jprot.2017.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 03/21/2017] [Accepted: 04/09/2017] [Indexed: 10/19/2022]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is a notorious rice pathogen that causes bacterial leaf blight (BLB), a destructive rice disease. Low-oxygen tension in the xylem vessels of rice stresses Xoo during infection. In this study, differentially expressed proteins under normoxic and hypoxic conditions were identified using high-performance liquid chromatography (HPLC) coupled with LC-MS/MS to investigate the global effects of low oxygen environment on Xoo PXO99A. A statistically validated list of 187 (normoxia) and 140 (hypoxia) proteins with functional assignments was generated, allowing the reconstruction of central metabolic pathways. Ten proteins involved in aromatic amino acid biosynthesis, glycolysis, butanoate metabolism, propanoate metabolism and biological adhesion were significantly modulated under low-oxygen tension. The genes encoded by these proteins were in-frame deleted, and three of them were determined to be required for full virulence in Xoo. The contributions of these three genes to important virulence-associated functions, including extracellular polysaccharide, cell motility and antioxidative ability, are presented. BIOLOGICAL SIGNIFICANCE To study how Xanthomonas oryzae pv. oryzae (Xoo) conquers low-oxygen tension in the xylem of rice, we identified differentially expressed proteins under normoxic and hypoxia. We found 140 proteins that uniquely expressed under the hypoxia were involved in 33 metabolism pathways. We identified 3 proteins were required for full virulence in Xoo and related to the ability of extracellular polysaccharide, cell motility, and antioxidative. This study is helpful for broadening our knowledge of the metabolism processed of Xoo in the xylem of rice.
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Affiliation(s)
- Jianliang Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jing Guo
- Agricultural Bioinformatics Key Laboratory of Hubei Province, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Shasha Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhiyong Zeng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Dehong Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiaoyan Yao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Haoquan Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lifang Ruan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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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: 2.4] [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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Zheng D, Yao X, Duan M, Luo Y, Liu B, Qi P, Sun M, Ruan L. Two overlapping two-component systems in Xanthomonas oryzae pv. oryzae contribute to full fitness in rice by regulating virulence factors expression. Sci Rep 2016; 6:22768. [PMID: 26957113 PMCID: PMC4783713 DOI: 10.1038/srep22768] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/19/2016] [Indexed: 01/17/2023] Open
Abstract
Two-component signal transduction systems (TCSs) are widely used by bacteria to adapt to the environment. In the present study, StoS (stress tolerance-related oxygen sensor) and SreKRS (salt response kinase, regulator, and sensor) were found to positively regulate extracellular polysaccharide (EPS) production and swarming in the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo). Surprisingly, the absence of stoS or sreKRS did not attenuate virulence. To better understand the intrinsic functions of StoS and SreKRS, quantitative proteomics isobaric tags for relative and absolute quantitation (iTRAQ) was employed. Consistent with stoS and sreK mutants exhibiting a similar phenotype, the signalling circuits of StoS and SreKRS overlapped. Carbohydrate metabolism proteins and chemotaxis proteins, which could be responsible for EPS and swarming regulation, respectively, were reprogrammed in stoS and sreK mutants. Moreover, StoS and SreKRS demonstrated moderate expression of the major virulence factor, hypersensitive response and pathogenicity (Hrp) proteins through the HrpG-HrpX circuit. Most importantly, Xoo equipped with StoS and SreKRS outcompetes strains without StoS or SreKRS in co-infected rice and grows outside the host. Therefore, we propose that StoS and SreKRS adopt a novel strategy involving the moderation of Hrp protein expression and the promotion of EPS and motility to adapt to the environment.
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Affiliation(s)
- Dehong Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xiaoyan Yao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Meng Duan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yufeng Luo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Biao Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Pengyuan Qi
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Lifang Ruan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
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Sahebi M, Taheri E, Tarighi S. CitB is required for full virulence of Xanthomonas oryzae pv. oryzae. World J Microbiol Biotechnol 2015; 31:1619-27. [PMID: 26250545 DOI: 10.1007/s11274-015-1914-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 07/29/2015] [Indexed: 11/28/2022]
Abstract
To identify novel virulence associated genes in Xanthomonas oryzae pv. oryzae (Xoo), a Xoo isolate (XooIR42), obtained from north of Iran, was selected to generate a mini-Tn5 transposon mutation library. One mutant (XooM176) that indicated reduced virulence on rice plants, while grew similar to wild type was selected. This mutant had an insertion in a coding region with 96% amino acid identity to a response regulator of Xoo KACC10331, citB (Xoo_RS12710). Genome analysis of Xoo KACC10331 indicated several genes including a flagelin protein (FlgL) and a chemotaxis protein (Xoo_RS12720) which were identified as virulence genes 4297 and 1403 nucleotides from the citB, respectively. The swarming motility, resistance to hydrogen peroxide, induced a hypersensitive response, in planta growth and pathogenicity were reduced in XooM176 mutant compared to that of wild-type. A plasmid containing the full citB gene of Xoo KACC10331was sufficient to complement the XooM176 mutant for lesion formation and resistance to hydrogen peroxide. We therefore propose that Xoo requires CitB for full pathogenicity in rice plants and also for protection against oxidative stress.
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Affiliation(s)
- Masood Sahebi
- Laboratory of Phytopathology, Department of Crop Protection, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Elaheh Taheri
- Laboratory of Phytopathology, Department of Crop Protection, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Saeed Tarighi
- Laboratory of Phytopathology, Department of Crop Protection, Ferdowsi University of Mashhad, Mashhad, Iran.
- Laboratory of Plant Pathology, Department of Crop Protection, Ferdowsi University of Mashhad, Mashhad, Iran.
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Leneveu-Jenvrin C, Connil N, Bouffartigues E, Papadopoulos V, Feuilloley MGJ, Chevalier S. Structure-to-function relationships of bacterial translocator protein (TSPO): a focus on Pseudomonas. Front Microbiol 2014; 5:631. [PMID: 25477872 PMCID: PMC4237140 DOI: 10.3389/fmicb.2014.00631] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 11/04/2014] [Indexed: 12/21/2022] Open
Abstract
The translocator protein (TSPO), which was previously designated as the peripheral-type benzodiazepine receptor, is a 3.5 billion year-old evolutionarily conserved protein expressed by most Eukarya, Archae and Bacteria, but its organization and functions differ remarkably. By taking advantage of the genomic data available on TSPO, we focused on bacterial TSPO and attempted to define functions of TSPO in Pseudomonas via in silico approaches. A tspo ortholog has been identified in several fluorescent Pseudomonas. This protein presents putative binding motifs for cholesterol and PK 11195, which is a specific drug ligand of mitochondrial TSPO. While it is a common surface distribution, the sense of insertion and membrane localization differ between α- and γ-proteobacteria. Experimental published data and STRING analysis of common TSPO partners in fluorescent Pseudomonas indicate a potential role of TSPO in the oxidative stress response, iron homeostasis and virulence expression. In these bacteria, TSPO could also take part in signal transduction and in the preservation of membrane integrity.
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Affiliation(s)
- Charlène Leneveu-Jenvrin
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| | - Nathalie Connil
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| | - Vassilios Papadopoulos
- Department of Medicine, Research Institute of the McGill University Health Centre, McGill University Montreal, QC, Canada
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
| | - Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment EA 4312, University of Rouen Evreux, France
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