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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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Lo HH, Chang HC, Wu YJ, Liao CT, Hsiao YM. Functional characterization and transcriptional analysis of degQ of Xanthomonas campestris pathovar campestris. J Basic Microbiol 2024; 64:e2300441. [PMID: 38470163 DOI: 10.1002/jobm.202300441] [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: 08/02/2023] [Revised: 01/07/2024] [Accepted: 01/20/2024] [Indexed: 03/13/2024]
Abstract
High-temperature-requirement protein A (HtrA) family proteins play important roles in controlling protein quality and are recognized as virulence factors in numerous animal and human bacterial pathogens. The role of HtrA family proteins in plant pathogens remains largely unexplored. Here, we investigated the HtrA family protein, DegQ, in the crucifer black rot pathogen Xanthomonas campestris pathovar campestris (Xcc). DegQ is essential for bacterial attachment and full virulence of Xcc. Moreover, the degQ mutant strain showed increased sensitivity to heat treatment and sodium dodecyl sulfate. Expressing the intact degQ gene in trans in the degQ mutant could reverse the observed phenotypic changes. In addition, we demonstrated that the DegQ protein exhibited chaperone-like activity. Transcriptional analysis displayed that degQ expression was induced under heat treatment. Our results contribute to understanding the function and expression of DegQ of Xcc for the first time and provide a novel perspective about HtrA family proteins in plant pathogen.
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Affiliation(s)
- Hsueh-Hsia Lo
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Hsiao-Ching Chang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yi-Jyun Wu
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
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Jaithon T, Atichakaro T, Phonphoem W, T-Thienprasert J, Sreewongchai T, T-Thienprasert NP. Potential usage of biosynthesized zinc oxide nanoparticles from mangosteen peel ethanol extract to inhibit Xanthomonas oryzae and promote rice growth. Heliyon 2024; 10:e24076. [PMID: 38234900 PMCID: PMC10792570 DOI: 10.1016/j.heliyon.2024.e24076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/16/2023] [Accepted: 01/03/2024] [Indexed: 01/19/2024] Open
Abstract
In recent decades, the biosynthesis of nanoparticles using biological agents, such as plant extracts, has grown in popularity due to their environmental and economic benefits. Therefore, this study investigated into utilizing ethanol crude extract sourced from mangosteen peel for the synthesis of zinc oxide nanoparticles (ZnO NPs) and assessing their efficacy against the rice blight pathogen (Xanthomonas oryzae pv. oryzae) through antibacterial evaluations. Additionally, the effects of the synthesized ZnO NPs on rice plant growth was investigated. The X-ray diffraction analysis revealed the production of wurtzite ZnO NPs under specific synthesis conditions, exhibiting a crystallite size of 38.71 nm (or 387.122 Å) without any contamination. Analysis of the ultraviolet-visible optical absorption spectrum indicated a characteristic absorption peak at 363 nm, suggesting a calculated band gap energy of 2.88 eV for the ZnO NPs. Furthermore, Fourier transform infrared spectroscopy analysis confirmed the presence of active compounds functional groups from mangosteen peel in the synthesized ZnO NPs. These biosynthesized ZnO NPs demonstrated significant inhibition of X. oryzae pv. oryzae growth, exhibiting an in vitro 50 % inhibitory concentration (IC50) value of 1.895 mg/mL and a minimum inhibitory concentration (MIC) value of 4 mg/mL. The ZnO NPs treatments at two-fold IC50 values significantly enhanced root length, dry biomass, and chlorophyll a content in rice plants. Consequently, the results demonstrated the potential application of biosynthesized ZnO NPs from mangosteen peel extract in green agriculture, as an alternative to excessive antibiotic use, for combating bacterial plant diseases, and for enhancing plant growth.
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Affiliation(s)
| | - Thamonwan Atichakaro
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Wannarat Phonphoem
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Jiraroj T-Thienprasert
- Department of Physics, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Thailand Center of Excellence in Physics, Ministry of Higher Education, Science, Research and Innovation, Bangkok, Thailand
| | - Tanee Sreewongchai
- Department of Agronomy, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
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Li R, Ren P, Liu Q, Yao J, Wu L, Zhu G, Xian X, Tang J, Lu G. McvR, a single domain response regulator regulates motility and virulence in the plant pathogen Xanthomonas campestris. MOLECULAR PLANT PATHOLOGY 2022; 23:649-663. [PMID: 35152521 PMCID: PMC8995066 DOI: 10.1111/mpp.13186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/19/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Signal transduction pathways mediated by sensor histidine kinases and cognate response regulators control a variety of physiological processes in response to environmental conditions in most bacteria. Comparatively little is known about the mechanism(s) by which single-domain response regulators (SD-RRs), which lack a dedicated output domain but harbour a phosphoryl receiver domain, exert their various regulatory effects in bacteria. Here we have examined the role of the SD-RR proteins encoded by the phytopathogen Xanthomonas campestris pv. campestris (Xcc). We describe the identification and characterization of a SD-RR protein named McvR (motility, chemotaxis, and virulence-related response regulator) that is required for virulence and motility regulation in Xcc. Deletion of the mcvR open reading frame caused reduced motility, chemotactic movement, and virulence in Xcc. Global transcriptome analyses revealed the McvR had a broad regulatory role and that most motility and pathogenicity genes were down-regulated in the mcvR mutant. Bacterial two-hybrid and protein pull-down assays revealed that McvR did not physically interact with components of the bacterial flagellum but interacts with other SD-RR proteins (like CheY) and the subset of DNA-binding proteins involved in gene regulation. Site-directed mutagenesis and phosphor-transfer experiments revealed that the aspartyl residue at position 55 of the receiver domain is important for phosphorylation and the regulatory activity of McvR protein. Taken together, the findings describe a previously unrecognized class of SD-RR protein that contributes to the regulation of motility and virulence in Xcc.
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Affiliation(s)
- Rui‐Fang Li
- Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsPlant Protection Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Pei‐Dong Ren
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Qian‐Qian Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Jia‐Li Yao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Liu Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Gui‐Ning Zhu
- Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsPlant Protection Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
| | - Xiao‐Yong Xian
- Guangxi Key Laboratory of Biology for Crop Diseases and Insect PestsPlant Protection Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
| | - Ji‐Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Guang‐Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
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Lo HH, Chang HC, Liao CT, Hsiao YM. Expression and function of clpS and clpA in Xanthomonas campestris pv. campestris. Antonie van Leeuwenhoek 2022; 115:589-607. [PMID: 35322326 DOI: 10.1007/s10482-022-01725-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 03/02/2022] [Indexed: 10/18/2022]
Abstract
ATP-dependent proteases (FtsH, Lon, and Clp family proteins) are ubiquitous in bacteria and play essential roles in numerous regulatory cell processes. Xanthomonas campestris pv. campestris is a Gram-negative pathogen that can cause black rot diseases in crucifers. The genome of X. campestris pv. campestris has several clp genes, namely, clpS, clpA, clpX, clpP, clpQ, and clpY. Among these genes, only clpX and clpP is known to be required for pathogenicity. Here, we focused on two uncharacterized clp genes (clpS and clpA) that encode the adaptor (ClpS) and ATPase subunit (ClpA) of the ClpAP protease complex. Transcriptional analysis revealed that the expression of clpS and clpA was growth phase-dependent and affected by the growth temperature. The inactivation of clpA, but not of clpS, resulted in susceptibility to high temperature and attenuated virulence in the host plant. The altered phenotypes of the clpA mutant could be complemented in trans. Site-directed mutagenesis revealed that K223 and K504 were the amino acid residues critical for ClpA function in heat tolerance. The protein expression profile shown by the clpA mutant in response to heat stress was different from that exhibited by the wild type. In summary, we characterized two clp genes (clpS and clpA) by examining their expression profiles and functions in different processes, including stress tolerance and pathogenicity. We demonstrated that clpS and clpA were expressed in a temperature-dependent manner and that clpA was required for the survival at high temperature and full virulence of X. campestris pv. campestris. This work represents the first time that clpS and clpA were characterized in Xanthomonas.
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Affiliation(s)
- Hsueh-Hsia Lo
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Hsiao-Ching Chang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan.
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Liao CT, Li CE, Chang HC, Hsu CH, Chiang YC, Hsiao YM. The lolB gene in Xanthomonas campestris pv. campestris is required for bacterial attachment, stress tolerance, and virulence. BMC Microbiol 2022; 22:17. [PMID: 34996353 PMCID: PMC8739992 DOI: 10.1186/s12866-021-02416-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 12/06/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Xanthomonas campestris pv. campestris (Xcc) is a Gram-negative bacterium that can cause black rot disease in crucifers. The lipoprotein outer membrane localization (Lol) system is involved in the lipoprotein sorting to the outer membrane. Although Xcc has a set of annotated lol genes, there is still little known about the physiological role in this phytopathogen. In this study, we aimed to characterize the role of LolB of Xcc in bacterial attachment, stress tolerance, and virulence. RESULTS To characterize the role of LolB, lolB mutant was constructed and phenotypic evaluation was performed. The lolB mutant revealed reductions in bacterial attachment, extracellular enzyme production, and virulence. Mutation of lolB also resulted in reduced tolerance to a myriad of stresses, including heat and a range of membrane-perturbing agents. Trans-complementation of lolB mutant with intact lolB gene reverted these altered phenotypes to the wild-type levels. From subsequent reporter assay and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis, the expression of genes that encode the major extracellular enzymes and the stress-related proteins was reduced after lolB mutation. CONCLUSIONS The results in this work contribute to the functional understanding of lolB in Xanthomonas for the first time, and provide new insights into the function of lolB in bacteria.
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Affiliation(s)
- Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Chih-En Li
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Hsiao-Ching Chang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Chien-Hui Hsu
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
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The Role of RelA and SpoT on ppGpp Production, Stress Response, Growth Regulation, and Pathogenicity in Xanthomonas campestris pv. campestris. Microbiol Spectr 2021; 9:e0205721. [PMID: 34935430 PMCID: PMC8693919 DOI: 10.1128/spectrum.02057-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The alarmone ppGpp plays an important role in the survival of bacteria by triggering the stringent response when exposed to environmental stress. Although Xanthomonas campestris pv. campestris (Xcc), which causes black rot disease in crucifers, is a representative species of Gram-negative phytopathogenic bacteria, relatively little is known regarding the factors influencing the stringent response in this species. However, previous studies in other Gram-negative bacteria have indicated that RelA and SpoT play a critical role in ppGpp synthesis. The current study found that these proteins also had an important role in Xcc, with a ΔrelAΔspoT double mutant being unable to produce ppGpp, resulting in changes to phenotype including reduced production of exopolysaccharides (EPS), exoenzymes, and biofilm, as well the loss of swarming motility and pathogenicity. The ppGpp-deficient mutant also exhibited greater sensitivity to environment stress, being almost incapable of growth on modified minimal medium (mMM) and having a much greater propensity to enter the viable but nonculturable (VBNC) state in response to oligotrophic conditions (0.85% NaCl). These findings much advance our understanding of the role of ppGpp in the biology of Xcc and could have important implications for more effective management of this important pathogen. IMPORTANCEXanthomonas campestris pv. campestris (Xcc) is a typical seedborne phytopathogenic bacterium that causes large economic losses worldwide, and this is the first original research article to investigate the role of ppGpp in this important species. Here, we revealed the function of RelA and SpoT in ppGpp production, physiology, pathogenicity, and stress resistance in Xcc. Most intriguingly, we found that ppGpp levels and downstream ppGpp-dependent phenotypes were mediated predominantly by SpoT, with RelA having only a supplementary role. Taken together, the results of the current study provide new insight into the role of ppGpp in the biology of Xcc, which could also have important implications for the role of ppGpp in the survival and pathogenicity of other pathogenic bacteria.
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Shaw RK, Shen Y, Wang J, Sheng X, Zhao Z, Yu H, Gu H. Advances in Multi-Omics Approaches for Molecular Breeding of Black Rot Resistance in Brassica oleracea L. FRONTIERS IN PLANT SCIENCE 2021; 12:742553. [PMID: 34938304 PMCID: PMC8687090 DOI: 10.3389/fpls.2021.742553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/20/2021] [Indexed: 06/14/2023]
Abstract
Brassica oleracea is one of the most important species of the Brassicaceae family encompassing several economically important vegetables produced and consumed worldwide. But its sustainability is challenged by a range of pathogens, among which black rot, caused by Xanthomonas campestris pv. campestris (Xcc), is the most serious and destructive seed borne bacterial disease, causing huge yield losses. Host-plant resistance could act as the most effective and efficient solution to curb black rot disease for sustainable production of B. oleracea. Recently, 'omics' technologies have emerged as promising tools to understand the host-pathogen interactions, thereby gaining a deeper insight into the resistance mechanisms. In this review, we have summarized the recent achievements made in the emerging omics technologies to tackle the black rot challenge in B. oleracea. With an integrated approach of the omics technologies such as genomics, proteomics, transcriptomics, and metabolomics, it would allow better understanding of the complex molecular mechanisms underlying black rot resistance. Due to the availability of sequencing data, genomics and transcriptomics have progressed as expected for black rot resistance, however, other omics approaches like proteomics and metabolomics are lagging behind, necessitating a holistic and targeted approach to address the complex questions of Xcc-Brassica interactions. Genomic studies revealed that the black rot resistance is a complex trait and is mostly controlled by quantitative trait locus (QTL) with minor effects. Transcriptomic analysis divulged the genes related to photosynthesis, glucosinolate biosynthesis and catabolism, phenylpropanoid biosynthesis pathway, ROS scavenging, calcium signalling, hormonal synthesis and signalling pathway are being differentially expressed upon Xcc infection. Comparative proteomic analysis in relation to susceptible and/or resistance interactions with Xcc identified the involvement of proteins related to photosynthesis, protein biosynthesis, processing and degradation, energy metabolism, innate immunity, redox homeostasis, and defence response and signalling pathways in Xcc-Brassica interaction. Specifically, most of the studies focused on the regulation of the photosynthesis-related proteins as a resistance response in both early and later stages of infection. Metabolomic studies suggested that glucosinolates (GSLs), especially aliphatic and indolic GSLs, its subsequent hydrolysis products, and defensive metabolites synthesized by jasmonic acid (JA)-mediated phenylpropanoid biosynthesis pathway are involved in disease resistance mechanisms against Xcc in Brassica species. Multi-omics analysis showed that JA signalling pathway is regulating resistance against hemibiotrophic pathogen like Xcc. So, the bonhomie between omics technologies and plant breeding is going to trigger major breakthroughs in the field of crop improvement by developing superior cultivars with broad-spectrum resistance. If multi-omics tools are implemented at the right scale, we may be able to achieve the maximum benefits from the minimum. In this review, we have also discussed the challenges, future prospects, and the way forward in the application of omics technologies to accelerate the breeding of B. oleracea for disease resistance. A deeper insight about the current knowledge on omics can offer promising results in the breeding of high-quality disease-resistant crops.
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Affiliation(s)
| | | | | | | | | | | | - Honghui Gu
- Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
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Su Q, Wang X, Leng M, Qi Y, Pang F, Tang J, Lu G. A HU-like protein is required for full virulence in Xanthomonas campestris pv. campestris. MOLECULAR PLANT PATHOLOGY 2021; 22:1574-1586. [PMID: 34424610 PMCID: PMC8578834 DOI: 10.1111/mpp.13128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/26/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
Bacteria harbour several abundant small DNA-binding proteins known as nucleoid-associated proteins (NAPs) that contribute to the structure of the bacterial nucleoid as well as to gene regulation. Although the function of NAPs as global transcriptional regulators has been comprehensively studied in the model organism Escherichia coli, their regulatory functions in other bacteria remain relatively poorly understood. Xanthomonas campestris pv. campestris (Xcc) is a gram-negative bacterium that causes black rot disease in almost all members of the crucifer family. In previous work, we demonstrated that a Fis homologue protein, which we named Fis-like protein (Flp), contributes to the regulation of virulence, type III secretion, and a series of other phenotypes in Xcc. Here we have examined the role of XC_1355, which is predicted to encode a DNA-binding protein belonging to the HU family herein named HU-like protein (Hlp). We show that mutation of XC_1355 in Xcc reduces the virulence, extracellular polysaccharide production, and cell motility, but has no effect on the production of extracellular enzymes and induction of the hypersensitive response. These data together with transcriptome analysis indicate that hlp is a previously uncharacterized gene involved in virulence that has partially overlapping and complementary functions with flp in Xcc, although the two regulators have opposite effects on the expression of genes involved in type III secretion. The findings add to our understanding of the complex regulatory pathways that act to regulate virulence in Xcc.
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Affiliation(s)
- Qian Su
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Xin‐Xin Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Ming Leng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Yan‐Hua Qi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Fu‐Yuan Pang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Ji‐Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Guang‐Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐bioresourcesCollege of Life Science and TechnologyGuangxi UniversityNanningChina
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Lin Y, Liao YY, Huang RX, Li AZ, An SQ, Tang JL, Tang DJ. Extracellular Amylase Is Required for Full Virulence and Regulated by the Global Posttranscriptional Regulator RsmA in Xanthomonas campestris Pathovar campestris. PHYTOPATHOLOGY 2021; 111:1104-1113. [PMID: 33245253 DOI: 10.1094/phyto-08-20-0372-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
As with many phytopathogenic bacteria, the virulence of Xanthomonas campestris pv. campestris, the causal agent of black rot disease in cruciferous plants, relies on secretion of a suite of extracellular enzymes that includes cellulase (endoglucanase), pectinase, protease, and amylase. Although the role in virulence of a number of these enzymes has been assessed, the contribution of amylase to X. campestris pv. campestris virulence has yet to be established. In this work, we investigated both the role of extracellular amylase in X. campestris pv. campestris virulence and the control of its expression. Deletion of XC3487 (here renamed amyAXcc), a putative amylase-encoding gene from the genome of X. campestris pv. campestris strain 8004, resulted in a complete loss of extracellular amylase activity and significant reduction in virulence. The extracellular amylase activity and virulence of the amyAXcc mutant could be restored to the wild-type level by expressing amyAXcc in trans. These results demonstrated that amyAXcc is responsible for the extracellular amylase activity of X. campestris pv. campestris and indicated that extracellular amylase plays an important role in X. campestris pv. campestris virulence. We also found that the expression of amyAXcc is strongly induced by starch and requires activation by the global posttranscriptional regulator RsmA. RsmA binds specifically to the 5'-untranslated region of amyAXcc transcripts, suggesting that RsmA regulates amyAXcc directly at the posttranscriptional level. Unexpectedly, in addition to posttranscriptional regulation, the use of a transcriptional reporter demonstrated that RsmA also regulates amyAXcc expression at the transcriptional level, possibly by an indirect mechanism.
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Affiliation(s)
- Yan Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Yong-Yan Liao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Ru-Xia Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Ai-Zhou Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Shi-Qi An
- National Biofilms Innovation Centre, Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
| | - Dong-Jie Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
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11
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Li CE, Liao CT, Lo HH, Hsiao YM. Functional Characterization and Transcriptional Analysis of clpP of Xanthomonas campestris pv. campestris. Curr Microbiol 2020; 77:2876-2885. [PMID: 32623486 DOI: 10.1007/s00284-020-02093-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/15/2020] [Indexed: 01/24/2023]
Abstract
The caseinolytic protease (Clp) system is essential for survival under stress conditions and for virulence in several pathogenic bacteria. Xanthomonas campestris pv. campestris (Xcc) is a plant pathogen which causes black rot disease in crucifers. In this study, the Xcc clpP gene which is annotated to encode the proteolytic core of Clp was characterized. Mutation of clpP resulted in susceptibility to high temperature and puromycin stresses. Site-directed mutagenesis revealed that S105, H130, and D179 are critical amino acid residues for ClpP function in puromycin tolerance. Inactivation of clpP also revealed an attenuation of virulence on the host plant and a reduction in the production of extracellular cellulase, mannanase, pectinase, and protease. The affected phenotypes of the clpP mutant could be complemented to wild-type levels by the intact clpP gene. Transcriptional analysis revealed that expression of clpP is induced under heat shock condition.
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Affiliation(s)
- Chih-En Li
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 406, Taiwan
| | - Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 406, Taiwan
| | - Hsueh-Hsia Lo
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 406, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 406, Taiwan.
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12
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Bansal K, Kumar S, Patil PB. Phylogenomic Insights into Diversity and Evolution of Nonpathogenic Xanthomonas Strains Associated with Citrus. mSphere 2020; 5:e00087-20. [PMID: 32295869 PMCID: PMC7160680 DOI: 10.1128/msphere.00087-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/18/2020] [Indexed: 01/24/2023] Open
Abstract
Xanthomonas species are primarily known as a group of phytopathogens infecting diverse plants. Recent molecular studies reveal the existence of potential novel species and strains of Xanthomonas following a nonpathogenic lifestyle. In the present study, we report whole-genome sequences of four nonpathogenic strains from citrus (NPXc). Taxonogenomics revealed the surprising diversity, as each of these three isolates were found to be potential novel species that together form a citrus-associated nonpathogenic Xanthomonas species complex (NPXc complex). Interestingly, this NPXc complex is related to another nonpathogenic species, Xanthomonas sontii, from rice (NPXr). On the other hand, the fourth NPXc isolate was found to be related to nonpathogenic isolates from walnut (NPXw); altogether, they form a potential taxonomic outlier of pathogenic Xanthomonas arboricola species. Furthermore, genomic investigation of well-characterized pathogenicity clusters in NPXc isolates revealed lifestyle-specific gene content dynamics. Primarily, genes essential for virulence (i.e., type 1 secretion system [T1SS], T2SS and its effectors, T3SS and its effectors, T4SS, T6SS, adhesins, and rpf gene cluster) and adaptation (i.e., gum, iron uptake and utilization, xanthomonadin, and two-component systems) were depicted by comparative genomics of a Xanthomonas community comprising diverse lifestyles. Overall, the present analysis confers that nonpathogenic isolates of diverse hosts phylogenomically converge and are evolving in parallel with their pathogenic counterparts. Hence, there is a need to understand the world of nonpathogenic isolates from diverse and economically important hosts. Genomic knowledge and resources of nonpathogenic strains will be invaluable in both basic and applied research of the genus XanthomonasIMPORTANCEXanthomonas citri is one of the top phytopathogenic bacteria and is the causal agent of citrus canker. Interestingly, Xanthomonas is also reported to be associated with healthy citrus plants. The advent of the genomic era enabled us to carry out a detailed evolutionary study of a Xanthomonas community associated with citrus and other plants. Our genome-based investigations have revealed hidden and extreme interstrain diversity of nonpathogenic Xanthomonas strains from citrus plants, warranting further large-scale studies. This indicates an unexplored world of Xanthomonas from healthy citrus plant species that may be coevolving as a species complex with the host, unlike the variant pathogenic species. The knowledge and genomic resources will be valuable in evolutionary studies exploring its hidden potential and management of pathogenic species.
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Affiliation(s)
- Kanika Bansal
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Sanjeet Kumar
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Prabhu B Patil
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
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13
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Yu Y, Ma J, Guo Q, Ma J, Wang H. A novel 3-oxoacyl-ACP reductase (FabG3) is involved in the xanthomonadin biosynthesis of Xanthomonas campestris pv. campestris. MOLECULAR PLANT PATHOLOGY 2019; 20:1696-1709. [PMID: 31560825 PMCID: PMC6859482 DOI: 10.1111/mpp.12871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot in crucifers, produces a membrane-bound yellow pigment called xanthomonadin to protect against photobiological and peroxidative damage, and uses a quorum-sensing mechanism mediated by the diffusible signal factor (DSF) family signals to regulate virulence factors production. The Xcc gene XCC4003, annotated as Xcc fabG3, is located in the pig cluster, which may be responsible for xanthomonadin synthesis. We report that fabG3 expression restored the growth of the Escherichia coli fabG temperature-sensitive mutant CL104 under non-permissive conditions. In vitro assays demonstrated that FabG3 catalyses the reduction of 3-oxoacyl-acyl carrier protein (ACP) intermediates in fatty acid synthetic reactions, although FabG3 had a lower activity than FabG1. Moreover, the fabG3 deletion did not affect growth or fatty acid composition. These results indicate that Xcc fabG3 encodes a 3-oxoacyl-ACP reductase, but is not essential for growth or fatty acid synthesis. However, the Xcc fabG3 knock-out mutant abolished xanthomonadin production, which could be only restored by wild-type fabG3, but not by other 3-oxoacyl-ACP reductase-encoding genes, indicating that Xcc FabG3 is specifically involved in xanthomonadin biosynthesis. Additionally, our study also shows that the Xcc fabG3-disrupted mutant affects Xcc virulence in host plants.
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Affiliation(s)
- Yonghong Yu
- Guangdong Food and Drug Vocational CollegeGuangzhouGuangdong510520China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Jianrong Ma
- Guangdong Food and Drug Vocational CollegeGuangzhouGuangdong510520China
| | - Qiaoqiao Guo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Jincheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
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14
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The clpX gene plays an important role in bacterial attachment, stress tolerance, and virulence in Xanthomonas campestris pv. campestris. Arch Microbiol 2019; 202:597-607. [PMID: 31741013 DOI: 10.1007/s00203-019-01772-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/20/2019] [Accepted: 11/07/2019] [Indexed: 01/24/2023]
Abstract
Xanthomonas campestris pv. campestris is a bacterial pathogen and the causal agent of black rot in crucifers. In this study, a clpX mutant was obtained by EZ-Tn5 transposon mutagenesis of the X. campestris pv. campestris. The clpX gene was annotated to encode ClpX, the ATP-binding subunit of ATP-dependent Clp protease. The clpX mutant exhibited reduced bacterial attachment, extracellular enzyme production and virulence. Mutation of clpX also resulted in increased sensitivity to a myriad of stresses, including heat, puromycin, and sodium dodecyl sulfate. These altered phenotypes of the clpX mutant could be restored to wild-type levels by in trans expression of the intact clpX gene. Proteomic analysis revealed that the expression of 211 proteins differed not less than twofold between the wild-type and mutant strains. Cluster of orthologous group analysis revealed that these proteins are mainly involved in metabolism, cell wall biogenesis, chaperone, and signal transduction. The reverse transcription quantitative real-time polymerase chain reaction analysis demonstrated that the expression of genes encoding attachment-related proteins, extracellular enzymes, and virulence-associated proteins was reduced after clpX mutation. The results in this study contribute to the functional understanding of the role of clpX in Xanthomonas for the first time, and extend new insights into the function of clpX in bacteria.
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15
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Shah SMA, Haq F, Ma W, Xu X, Wang S, Xu Z, Zou L, Zhu B, Chen G. Tal1 NXtc01 in Xanthomonas translucens pv. cerealis Contributes to Virulence in Bacterial Leaf Streak of Wheat. Front Microbiol 2019; 10:2040. [PMID: 31551976 PMCID: PMC6737349 DOI: 10.3389/fmicb.2019.02040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/19/2019] [Indexed: 12/21/2022] Open
Abstract
Xanthomonas translucens pv. cerealis (Xtc) causes bacterial leaf streak (BLS) of important cereal crops, including wheat (Triticum aestivum) and barley (Hordeum vulgare). Transcription activator-like effectors (TALEs) play vital roles in many plant diseases caused by Xanthomonas spp., however, TALEs have not been previously characterized in Xtc. In this study, the whole genome of NXtc01, a virulent strain of Xtc from Xinjiang, China, was sequenced and compared with genomes of other Xanthomonas spp. Xtc NXtc01 consists of a single 4,622,298 bp chromosome that encodes 4,004 genes. Alignment of the NXtc01 sequence with the draft genome of Xtc strain CFBP 2541 (United States) revealed a single giant inversion and differences in the location of two tal genes, which were designated tal1 and tal2. In NXtc01, both tal genes are located on the chromosome, whereas tal2 is plasmid-encoded in CFBP 2541. The repeat variable diresidues (RVDs) at the 12th and 13th sites within Tal2 repeat units were identical in both strains, whereas Tal1 showed differences in the third RVD. Xtc NXtc01 and CFBP 2541 encoded 35 and 33 non-TALE type III effectors (T3Es), respectively. tal1, tal2, and tal-free deletion mutants of Xtc NXtc01 were constructed and evaluated for virulence. The tal1 and tal-free deletion mutants were impaired with respect to symptom development and growth in wheat, suggesting that tal1 is a virulence factor in NXtc01. This was confirmed in gain-of-function experiments that showed the introduction of tal1, but not tal2, restored virulence to the tal-free mutant. Furthermore, we generated a hrcC deletion mutant of NXtc01; the hrcC mutant was non-pathogenic on wheat and unable to elicit a hypersensitive response in the non-host Nicotiana benthamiana. Our data provide a platform for exploring the roles of both TALEs and non-TALEs in promoting BLS on wheat.
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Affiliation(s)
- Syed Mashab Ali Shah
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Fazal Haq
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Wenxiu Ma
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xiameng Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Sai Wang
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Zhengyin Xu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Lifang Zou
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Bo Zhu
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- School of Agriculture and Biology/State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
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16
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Li RF, Cui P, Wei PZ, Liu XY, Tang JL, Lu GT. HprK Xcc is a serine kinase that regulates virulence in the Gram-negative phytopathogen Xanthomonas campestris. Environ Microbiol 2019; 21:4504-4520. [PMID: 31301270 PMCID: PMC6916182 DOI: 10.1111/1462-2920.14740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/09/2019] [Accepted: 07/11/2019] [Indexed: 11/28/2022]
Abstract
The HprK serine kinase is a component of the phosphoenolpyruvate phosphotransferase system (PTS) of bacteria that generally regulates catabolite repression through phosphorylation/dephosphorylation of the PTS protein PtsH at a conserved serine residue. However, many bacteria do not encode a complete PTS or even have an HprK homologue. Xanthomonas campestris pv. campestris (Xcc) is a pathogen that cause black rot disease in crucifer plants and one of the few Gram-negative bacteria that encodes a homologue of HprK protein (herein HprKXcc ). To gain insight into the role of HprKXcc and other PTS-related components in Xcc we individually mutated and phenotypically assessed the resulting strains. Deletion of hprK Xcc demonstrated its requirement for virulence and other diverse cellular processes associated including extracellular enzyme activity, extracellular-polysaccharide production and cell motility. Global transcriptome analyses revealed the HprKXcc had a broad regulatory role in Xcc. Additionally, through overexpression, double gene deletion and transcriptome analysis we demonstrated that hprK Xcc shares an epistatic relationship with ptsH. Furthermore, we demonstrate that HprKXcc is a functional serine kinase, which has the ability to phosphorylate PtsH. Taken together, the data illustrates the previously unappreciated global regulatory role of HprKXcc and previously uncharacterized PTS components that control virulence in this pathogen.
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Affiliation(s)
- Rui-Fang Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China.,Guangxi Key Laboratory of Biology for Crop Diseases and Insect Pests, Plant Protection Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Ping Cui
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Ping-Zhen Wei
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Xing-Yan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Guang-Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
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17
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Athinuwat D, Brooks S. The OmpA Gene of Xanthomonas axonopodis pv. glycines is Involved in Pathogenesis of Pustule Disease on Soybean. Curr Microbiol 2019; 76:879-887. [PMID: 31089795 DOI: 10.1007/s00284-019-01702-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/06/2019] [Indexed: 10/26/2022]
Abstract
The goal of this study was to elucidate the role of the outer membrane protein A (ompA) gene of Xanthomonas axonopodis pv. glycines in bacterial pustule pathogenesis of soybean. An ompA mutant of X. axonopodis pv. glycines KU-P-SW005 was shown to significantly decrease cellulase, pectate lyase, and polysaccharide production. The production of these proteins in the ompA mutant was approximately five times lower than that of the wildtype. The ompA mutant also exhibited modified biofilm development. More importantly, the mutant reduced disease severity to the soybean. Ten days after inoculation, the virulence rating of the susceptible soybean cv. SJ4 inoculated with the ompA mutant was 11.23%, compared with 87.98% for the complemented ompA mutant. Production of cellulase, pectate lyase, polysaccharide was restored, biofilm, and pustule numbers were restored in the complemented ompA mutant that did not differ from the wild type. Taken together, these data suggest that OmpA-mediated invasion plays an important role in protein secretion during pathogenesis to soybean.
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Affiliation(s)
- Dusit Athinuwat
- Department of Agricultural Technology, Faculty of Science and Technology, Thammasat University, Pathumthani, Thailand.
| | - Siraprapa Brooks
- School of Science, Mae Fah Luang University, Chaing Rai, 57100, Thailand
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18
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Knorst V, Byrne S, Yates S, Asp T, Widmer F, Studer B, Kölliker R. Pooled DNA sequencing to identify SNPs associated with a major QTL for bacterial wilt resistance in Italian ryegrass (Lolium multiflorum Lam.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2019; 132:947-958. [PMID: 30506318 PMCID: PMC6449324 DOI: 10.1007/s00122-018-3250-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/23/2018] [Indexed: 05/27/2023]
Abstract
SNPs and candidate genes associated with bacterial wilt resistance in Italian ryegrass were identified by sequencing the parental plants and pooled F1 progeny of a segregating population. Italian ryegrass (Lolium multiflorum Lam.) is one of the most important forage grass species in temperate regions. Its yield, quality and persistency can significantly be reduced by bacterial wilt, a serious disease caused by Xanthomonas translucens pv. graminis. Although a major QTL for bacterial wilt resistance has previously been reported, detailed knowledge on underlying genes and DNA markers to allow for efficient resistance breeding strategies is currently not available. We used pooled DNA sequencing to characterize a major QTL for bacterial wilt resistance of Italian ryegrass and to develop inexpensive sequence-based markers to efficiently target resistance alleles for marker-assisted recurrent selection. From the mapping population segregating for the QTL, DNA of 44 of the most resistant and 44 of the most susceptible F1 individuals was pooled and sequenced using the Illumina HiSeq 2000 platform. Allele frequencies of 18 × 106 single nucleotide polymorphisms (SNP) were determined in the resistant and susceptible pool. A total of 271 SNPs on 140 scaffold sequences of the reference parental genome showed significantly different allele frequencies in both pools. We converted 44 selected SNPs to KASP™ markers, genetically mapped these proximal to the major QTL and thus validated their association with bacterial wilt resistance. This study highlights the power of pooled DNA sequencing to efficiently target binary traits in biparental mapping populations. It delivers genome sequence data, SNP markers and potential candidate genes which will allow to implement marker-assisted strategies to fix bacterial wilt resistance in outcrossing breeding populations of Italian ryegrass.
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Affiliation(s)
- Verena Knorst
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, 8092, Zurich, Switzerland
- Molecular Ecology, Agroscope, Reckenholzstrasse 191, 8046, Zurich, Switzerland
| | - Stephen Byrne
- Crops Science Department, Teagasc, Oak Park, Carlow, R93 XE12, Ireland
| | - Steven Yates
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, 8092, Zurich, Switzerland
| | - Torben Asp
- Department of Molecular Biology and Genetics, Section for Crop Genetics and Biotechnology, Forsøgsvej 1, 4200, Slagelse, Denmark
| | - Franco Widmer
- Molecular Ecology, Agroscope, Reckenholzstrasse 191, 8046, Zurich, Switzerland
| | - Bruno Studer
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, 8092, Zurich, Switzerland
| | - Roland Kölliker
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, 8092, Zurich, Switzerland.
- Molecular Ecology, Agroscope, Reckenholzstrasse 191, 8046, Zurich, Switzerland.
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19
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Wu L, Ma L, Li X, Huang Z, Gao X. Contribution of the cold shock protein CspA to virulence in Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT PATHOLOGY 2019; 20:382-391. [PMID: 30372574 PMCID: PMC6637868 DOI: 10.1111/mpp.12763] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) causes a damaging bacterial leaf blight disease in rice. Cold shock proteins (Csps) are highly conserved nucleic acid-binding proteins present in various bacterial genera, but relatively little is known about their functions in Xanthomonas. Herein, we identified four Csps (CspA-CspD) in the Xoo PXO99A strain. Deletion of cspA decreased cold adaptation and a few known pathogenic factors, including bacterial pathogenicity, biofilm formation and polysaccharide production. Furthermore, we performed transcriptomic and chromosome immunoprecipitation (ChIP) experiments to identify direct targets of CspA and to determine its DNA-binding sequence. Integrative data analysis revealed that CspA directly regulates two genes, PXO_RS11830 and PXO_RS01060, by binding to a conserved CCAAT sequence in the promoter region. We generated single-deletion mutants of each gene and the results indicate that both are responsible for Xanthomonas pathogenicity. In addition, quantitative real-time polymerase chain reaction and western blotting showed that CspA suppressed the expression of its direct targets. In summary, our study clarifies the characteristics of Csps in Xanthomonas and greatly advances our understanding of the mechanisms underlying the contribution of CspA to bacterial virulence.
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Affiliation(s)
- Liming Wu
- College of Plant ProtectionNanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of EducationNanjing210095China
| | - Liumin Ma
- College of Plant ProtectionNanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of EducationNanjing210095China
| | - Xi Li
- College of Plant ProtectionNanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of EducationNanjing210095China
| | - Ziyang Huang
- College of Plant ProtectionNanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of EducationNanjing210095China
| | - Xuewen Gao
- College of Plant ProtectionNanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, Ministry of EducationNanjing210095China
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20
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Liao CT, Chiang YC, Hsiao YM. Functional characterization and proteomic analysis of lolA in Xanthomonas campestris pv. campestris. BMC Microbiol 2019; 19:20. [PMID: 30665348 PMCID: PMC6341742 DOI: 10.1186/s12866-019-1387-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 01/02/2019] [Indexed: 12/31/2022] Open
Abstract
Background The gram-negative Xanthomonas campestris pv. campestris is the pathogenic bacterium that causes black rot disease in crucifers. The virulence determinants of this bacterium include extracellular enzymes, exopolysaccharides, and biofilm formation. Here, one transposon mutant of X. campestris pv. campestris strain 17 that affects biofilm formation was isolated, and subsequent analyses led to the identification of the lolA gene, which encodes an outer membrane lipoprotein chaperone. Results The lolA mutant exhibited significant reductions in bacterial attachment, extracellular enzyme production, virulence, and tolerance in the presence of myriad membrane-perturbing agents. These phenotypic changes of the mutant could be complemented to the wild-type level through the intact lolA gene. Proteomic analysis revealed that 109 proteins were differentially expressed after lolA mutation. These differentially expressed proteins were categorized in various functional groups and were mainly associated with the membrane component, were involved in transport, and contained receptor activity. Through reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis, deletion of lolA was determined to have caused significantly reduced expression of genes that encode the major extracellular enzymes, the biofilm-related proteins, and the virulence-related proteins. The RT-qPCR analysis also indicated that the expression of several genes that encode putative outer membrane lipoproteins and TonB-dependent receptors was reduced after lolA mutation. Conclusions This is the first report to define the lolA gene as a virulence factor and to contribute to the functional understanding of, and provide new information concerning, the role of lolA in Xanthomonas. Furthermore, the results of this study provide and extend new insights into the function of lolA in bacteria. Electronic supplementary material The online version of this article (10.1186/s12866-019-1387-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
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21
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Liu YF, Liao CT, Chiang YC, Li CE, Hsiao YM. WxcX is involved in bacterial attachment and virulence in Xanthomonas campestris pv. campestris. J Basic Microbiol 2018; 58:403-413. [PMID: 29504631 DOI: 10.1002/jobm.201700591] [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: 10/25/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 11/08/2022]
Abstract
Xanthomonas campestris pv. campestris (Xcc) is the causative agent of black rot in crucifers. Here, one EZ-Tn5 transposon mutant of Xcc, altered in bacterial attachment, was isolated. Further analysis revealed that the transposon was inserted in the wxcX gene (encodes a hypothetical protein) of the transposon mutant. Sequence analysis revealed that WxcX is highly conserved in Xanthomonas, but none has been characterized. In this study, it was indicated that mutation of wxcX resulted in enhanced bacterial attachment, reduced virulence on the host cabbage, and increased sensitivity to sodium dodecyl sulfate. The affected phenotypes of the wxcX mutant could be complemented to wild-type levels by the intact wxcX gene. Site-directed mutagenesis revealed that E408 and E411 are critical amino acid residues for WxcX function in bacterial attachment. Taken together, our results demonstrate the roles of wxcX in attachment, virulence, and tolerance to sodium dodecyl sulfate in Xanthomonas for the first time.
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Affiliation(s)
- Yu-Fan Liu
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan.,Division of Allergy, Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Chih-En Li
- Graduate Institute of Biotechnology and Biomedical Engineering, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
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22
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Wang B, Wu G, Zhang Y, Qian G, Liu F. Dissecting the virulence-related functionality and cellular transcription mechanism of a conserved hypothetical protein in Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT PATHOLOGY 2018; 19:1859-1872. [PMID: 29392817 PMCID: PMC6638143 DOI: 10.1111/mpp.12664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/23/2018] [Accepted: 01/29/2018] [Indexed: 05/09/2023]
Abstract
Hypothetical proteins without defined functions are largely distributed in all sequenced bacterial genomes. Understanding their potent functionalities is a basic demand for bacteriologists. Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight of rice, is one of the model systems for the study of molecular plant pathology. One-quarter of proteins in the genome of this bacterium are defined as hypothetical proteins, but their roles in Xoo pathogenicity are unknown. Here, we generated in-frame deletions for six hypothetical proteins selected from strain PXO99A and found that one of them (PXO_03177) is required for the full virulence of this strain. PXO_03177 is conserved in Xanthomonas, and is predicted to contain two domains relating to polysaccharide synthesis. However, we found that mutation of this gene did not affect the production or modification of extracellular polysaccharides (EPSs) and lipopolysaccharides (LPSs), two major polysaccharides produced by Xoo relating to its infection. Interestingly, we found that inactivation of PXO_03177 significantly impaired biofilm formation and tolerance to sodium dodecyl sulfate (SDS), both of which are considered to play key roles during Xoo infection in rice leaves. These findings thus enable us to define a function for PXO_03177 in the virulence of Xoo. Furthermore, we also found that the global regulator Clp controls the transcription of PXO_03177 by direct binding to its promoter region, presenting the first cellular regulatory pathway for the modulation of expression of this hypothetical protein gene. Our results provide reference information for PXO_03177 homologues in Xanthomonas.
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Affiliation(s)
- Bo Wang
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
| | - Guichun Wu
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
| | - Yuqiang Zhang
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
| | - Guoliang Qian
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
| | - Fengquan Liu
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural UniversityNanjing 210095China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Nanjing Agricultural University), Ministry of EducationNanjing 210095China
- Institute of Plant Protection, Jiangsu Academy of Agricultural SciencesNanjing 210014China
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23
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XCC2366, A Gene Encoding A Putative TetR Family Transcriptional Regulator, is Required for Acriflavin Resistance and Virulence of Xanthomonas campestris pv. campestris. Curr Microbiol 2017; 74:1373-1381. [DOI: 10.1007/s00284-017-1328-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/04/2017] [Indexed: 10/19/2022]
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24
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Falahi Charkhabi N, Booher NJ, Peng Z, Wang L, Rahimian H, Shams-Bakhsh M, Liu Z, Liu S, White FF, Bogdanove AJ. Complete Genome Sequencing and Targeted Mutagenesis Reveal Virulence Contributions of Tal2 and Tal4b of Xanthomonas translucens pv. undulosa ICMP11055 in Bacterial Leaf Streak of Wheat. Front Microbiol 2017; 8:1488. [PMID: 28848509 PMCID: PMC5554336 DOI: 10.3389/fmicb.2017.01488] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/24/2017] [Indexed: 12/31/2022] Open
Abstract
Bacterial leaf streak caused by Xanthomonas translucens pv. undulosa (Xtu) is an important disease of wheat (Triticum aestivum) and barley (Hordeum vulgare) worldwide. Transcription activator-like effectors (TALEs) play determinative roles in many of the plant diseases caused by the different species and pathovars of Xanthomonas, but their role in this disease has not been characterized. ICMP11055 is a highly virulent Xtu strain from Iran. The aim of this study was to better understand genetic diversity of Xtu and to assess the role of TALEs in bacterial leaf streak of wheat by comparing the genome of this strain to the recently completely sequenced genome of a U.S. Xtu strain, and to several other draft X. translucens genomes, and by carrying out mutational analyses of the TALE (tal) genes the Iranian strain might harbor. The ICMP11055 genome, including its repeat-rich tal genes, was completely sequenced using single molecule, real-time technology (Pacific Biosciences). It consists of a single circular chromosome of 4,561,583 bp, containing 3,953 genes. Whole genome alignment with the genome of the United States Xtu strain XT4699 showed two major re-arrangements, nine genomic regions unique to ICMP11055, and one region unique to XT4699. ICMP110055 harbors 26 non-TALE type III effector genes and seven tal genes, compared to 25 and eight for XT4699. The tal genes occur singly or in pairs across five scattered loci. Four are identical to tal genes in XT4699. In addition to common repeat-variable diresidues (RVDs), the tal genes of ICMP11055, like those of XT4699, encode several RVDs rarely observed in Xanthomonas, including KG, NF, Y∗, YD, and YK. Insertion and deletion mutagenesis of ICMP11055 tal genes followed by genetic complementation analysis in wheat cv. Chinese Spring revealed that Tal2 and Tal4b of ICMP11055 each contribute individually to the extent of disease caused by this strain. A largely conserved ortholog of tal2 is present in XT4699, but for tal4b, only a gene with partial, fragmented RVD sequence similarity can be found. Our results lay the foundation for identification of important host genes activated by Xtu TALEs as targets for the development of disease resistant varieties.
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Affiliation(s)
- Nargues Falahi Charkhabi
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States.,Department of Plant Pathology, Tarbiat Modares UniversityTehran, Iran
| | - Nicholas J Booher
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
| | - Zhao Peng
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States.,Department of Plant Pathology, University of Florida, GainesvilleFL, United States
| | - Li Wang
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
| | - Heshmat Rahimian
- Department of Plant Protection, Sari Agricultural Science and Natural Resources UniversitySari, Iran
| | | | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, FargoND, United States
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States
| | - Frank F White
- Department of Plant Pathology, Kansas State University, ManhattanKS, United States.,Department of Plant Pathology, University of Florida, GainesvilleFL, United States
| | - Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, IthacaNY, United States
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25
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Bansal K, Midha S, Kumar S, Patil PB. Ecological and Evolutionary Insights into Xanthomonas citri Pathovar Diversity. Appl Environ Microbiol 2017; 83:e02993-16. [PMID: 28258140 PMCID: PMC5394309 DOI: 10.1128/aem.02993-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/22/2017] [Indexed: 11/20/2022] Open
Abstract
Citrus canker, caused by Xanthomonas citri pv. citri, is a serious disease of citrus plants worldwide. Earlier phylogenetic studies using housekeeping genes revealed that X. citri pv. citri is related to many other pathovars, which can be collectively referred as Xanthomonas citri pathovars (XCPs). From the present study, we report the genome sequences of 18 XCPs and compared them with four XCPs available in the public domain. In a tree based on phylogenomic marker genes, all the XCPs form a monophyletic cluster, suggesting their origin from a common ancestor. Phylogenomic analysis using the type strain further established that all the XCPs belong to one species. Clonal analysis of the core genome revealed the presence of two major lineages within this monophyletic cluster consisting of some clonal variants. Incidentally, the majority of these XCPs were first noticed in India, corroborating their clonal relationship and their common origin. Comparative analysis revealed an open pan-genome and the role of interstrain genomic flux of these XCPs since their diversification from a common ancestor. Even though there are wide variations in type III gene effectomes, we identified three core effectors which can be valuable in resistance-breeding programs. Overall, genomic examination of ecological relatives allowed us to dissect the tremendous genomic potential of X. citri species to rapidly evolve into specialized strains infecting diverse crop plants.IMPORTANCE Host specialization is one of the characteristic features of highly evolved pathogens such as the Xanthomonas group of phytopathogenic bacteria. Since the hosts involve staple crops and economically important fruits such as citrus, detailed understanding of the diversity and evolution of such strains infecting diverse plants is important for quarantine purposes. In the present study, we carried out genomic investigation of members of a phylogenetically and ecologically defined group of Xanthomonas strains pathogenic to diverse plants, including citrus. This group includes the oldest Xanthomonas pathovars and also recently emerged pathovars in a particular country where they are endemic. Our high-throughput genomic study has provided novel insights into the evolution of a unique lineage consisting of serious pathogens and their ecological relatives, suggesting the nature, scope, and pattern of rapid and recent diversification. Further, from the level of species to that of clonal variants, the study revealed interesting genomic patterns in diversification of a Xanthomonas lineage and perhaps will inspire careful study of the host range of the included pathovars.
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Affiliation(s)
- Kanika Bansal
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Samriti Midha
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Sanjeet Kumar
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Prabhu B Patil
- CSIR-Institute of Microbial Technology, Chandigarh, India
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26
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Functional characterization and transcriptional analysis of icd2 gene encoding an isocitrate dehydrogenase of Xanthomonas campestris pv. campestris. Arch Microbiol 2017; 199:917-929. [DOI: 10.1007/s00203-017-1370-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/02/2017] [Accepted: 03/21/2017] [Indexed: 10/19/2022]
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27
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Bianco MI, Toum L, Yaryura PM, Mielnichuk N, Gudesblat GE, Roeschlin R, Marano MR, Ielpi L, Vojnov AA. Xanthan Pyruvilation Is Essential for the Virulence of Xanthomonas campestris pv. campestris. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:688-699. [PMID: 27464764 DOI: 10.1094/mpmi-06-16-0106-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Xanthan, the main exopolysaccharide (EPS) synthesized by Xanthomonas spp., contributes to bacterial stress tolerance and enhances attachment to plant surfaces by helping in biofilm formation. Therefore, xanthan is essential for successful colonization and growth in planta and has also been proposed to be involved in the promotion of pathogenesis by calcium ion chelation and, hence, in the suppression of the plant defense responses in which this cation acts as a signal. The aim of this work was to study the relationship between xanthan structure and its role as a virulence factor. We analyzed four Xanthomonas campestris pv. campestris mutants that synthesize structural variants of xanthan. We found that the lack of acetyl groups that decorate the internal mannose residues, ketal-pyruvate groups, and external mannose residues affects bacterial adhesion and biofilm architecture. In addition, the mutants that synthesized EPS without pyruvilation or without the external mannose residues did not develop disease symptoms in Arabidopsis thaliana. We also observed that the presence of the external mannose residues and, hence, pyruvilation is required for xanthan to suppress callose deposition as well as to interfere with stomatal defense. In conclusion, pyruvilation of xanthan seems to be essential for Xanthomonas campestris pv. campestris virulence.
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Affiliation(s)
- María Isabel Bianco
- 1 Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Saladillo 2468 (C1440FFX), Ciudad de Buenos Aires, Argentina
| | - Laila Toum
- 1 Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Saladillo 2468 (C1440FFX), Ciudad de Buenos Aires, Argentina
| | - Pablo Marcelo Yaryura
- 2 Centro de Investigaciones y Transferencia (CIT Villa María), CONICET-Instituto de Ciencias Básicas y Aplicadas, Universidad Nacional de Villa María. Av. Arturo Jauretche 1555, (5900), Villa María, Córdoba, Argentina
| | - Natalia Mielnichuk
- 1 Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Saladillo 2468 (C1440FFX), Ciudad de Buenos Aires, Argentina
| | - Gustavo Eduardo Gudesblat
- 1 Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Saladillo 2468 (C1440FFX), Ciudad de Buenos Aires, Argentina
- 3 Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Departamento de Biodiversidad y Biología Experimental (DBBE), CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Buenos Aires (C1428EGA), Argentina
| | - Roxana Roeschlin
- 4 Instituto de Biología Molecular y Celular de Rosario (IBR)-CONICET, Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda s/n, (S2000FHN) Rosario, Argentina; and
| | - María Rosa Marano
- 4 Instituto de Biología Molecular y Celular de Rosario (IBR)-CONICET, Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda s/n, (S2000FHN) Rosario, Argentina; and
| | - Luis Ielpi
- 5 Laboratorio de Genética Bacteriana, Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA)-CONICET, Patricias Argentinas 435 (C1405BWE), Ciudad de Buenos Aires, Argentina
| | - Adrián A Vojnov
- 1 Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Saladillo 2468 (C1440FFX), Ciudad de Buenos Aires, Argentina
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28
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de Oliveira AG, Spago FR, Simionato AS, Navarro MOP, da Silva CS, Barazetti AR, Cely MVT, Tischer CA, San Martin JAB, de Jesus Andrade CGT, Novello CR, Mello JCP, Andrade G. Bioactive Organocopper Compound from Pseudomonas aeruginosa Inhibits the Growth of Xanthomonas citri subsp. citri. Front Microbiol 2016; 7:113. [PMID: 26903992 PMCID: PMC4746251 DOI: 10.3389/fmicb.2016.00113] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 01/22/2016] [Indexed: 11/22/2022] Open
Abstract
Citrus canker is a very destructive disease of citrus species. The challenge is to find new compounds that show strong antibiotic activity and low toxicity to plants and the environment. The objectives of the present study were (1) to extract, purify and evaluate the secondary metabolites with antibiotic activity produced by Pseudomonas aeruginosa LV strain in vitro against Xanthomonas citri subsp. citri (strain 306), (2) to determine the potential of semi-purified secondary metabolites in foliar application to control citrus canker under greenhouse conditions, and (3) to identify antibiotic activity in orange leaf mesophyll infected with strain 306, by electron microscopy. Two pure bioactive compounds were isolated, an organocopper antibiotic compound (OAC) and phenazine-1-carboxamide. Phenazine-1-carboxamide did not show any antibiotic activity under the experimental conditions used in this study. The OAC showed a high level of antibiotic activity with a minimum inhibitory concentration of 0.12 μg mL(-1). In greenhouse tests for control of citrus canker in orange trees, the semi-purified fraction F3d reduced lesion formation by about 97%. The concentration used was 500 times lower than that for the recommended commercial copper-based product. Electron microscopy showed that F3d altered the exopolysaccharide matrix and caused cell lysis of the pathogen inside the citrus canker lesions. These results suggest that secondary metabolites produced by inducing P. aeruginosa LV strain have a high potential to be used as a bioproduct to control citrus canker.
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Affiliation(s)
- Admilton G. de Oliveira
- Laboratório de Ecologia Microbiana, Departamento de Microbiologia, Universidade Estadual de LondrinaLondrina, Brazil
| | - Flavia R. Spago
- Laboratório de Ecologia Microbiana, Departamento de Microbiologia, Universidade Estadual de LondrinaLondrina, Brazil
| | - Ane S. Simionato
- Laboratório de Ecologia Microbiana, Departamento de Microbiologia, Universidade Estadual de LondrinaLondrina, Brazil
| | - Miguel O. P. Navarro
- Laboratório de Ecologia Microbiana, Departamento de Microbiologia, Universidade Estadual de LondrinaLondrina, Brazil
| | - Caroline S. da Silva
- Laboratório de Ecologia Microbiana, Departamento de Microbiologia, Universidade Estadual de LondrinaLondrina, Brazil
| | - André R. Barazetti
- Laboratório de Ecologia Microbiana, Departamento de Microbiologia, Universidade Estadual de LondrinaLondrina, Brazil
| | - Martha V. T. Cely
- Laboratório de Ecologia Microbiana, Departamento de Microbiologia, Universidade Estadual de LondrinaLondrina, Brazil
| | - Cesar A. Tischer
- Laboratório de Espectroscopia, Departamento de Bioquímica e Biotecnologia, Universidade Estadual de LondrinaLondrina, Brazil
| | - Juca A. B. San Martin
- Laboratório de Microscopia Eletrônica e Microanálise, Departamento de Biologia Geral, Universidade Estadual de LondrinaLondrina, Brazil
| | - Célia G. T. de Jesus Andrade
- Laboratório de Microscopia Eletrônica e Microanálise, Departamento de Biologia Geral, Universidade Estadual de LondrinaLondrina, Brazil
| | - Cláudio R. Novello
- Laboratório de Produtos Fitoterápicos, Departamento de Farmácia e Farmacologia, Universidade Estadual de MaringáMaringá, Brazil
| | - João C. P. Mello
- Laboratório de Produtos Fitoterápicos, Departamento de Farmácia e Farmacologia, Universidade Estadual de MaringáMaringá, Brazil
| | - Galdino Andrade
- Laboratório de Ecologia Microbiana, Departamento de Microbiologia, Universidade Estadual de LondrinaLondrina, Brazil
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29
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Lee HM, Liao CT, Chiang YC, Chang YY, Yeh YT, Du SC, Hsiao YM. Characterization of genes encoding proteins containing HD-related output domain in Xanthomonas campestris pv. campestris. Antonie van Leeuwenhoek 2016; 109:509-22. [PMID: 26821378 DOI: 10.1007/s10482-016-0656-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 01/19/2016] [Indexed: 11/30/2022]
Abstract
The Gram-negative plant pathogen Xanthomonas campestris pv. campestris (Xcc) is the causative agent of black rot in crucifers. The production of Xcc virulence factors is regulated by Clp and RpfF. HD-related output domain (HDOD) is a protein domain of unknown biochemical function. The genome of Xcc encodes three proteins (GsmR, HdpA, and HdpB) with an HDOD. The GsmR has been reported to play a role in the general stress response and cell motility and its expression is positively regulated by Clp. Here, the function and transcription of hdpA and hdpB were characterized. Mutation of hdpA resulted in enhanced bacterial attachment. In addition, the expression of hdpA was positively regulated by RpfF but not by Clp, subject to catabolite repression and affected by several stress conditions. However, mutational analysis and reporter assay showed that hdpB had no effect on the production of a range of virulence factors and its expression was independent of Clp and RpfF. The results shown here not only extend the previous work on RpfF regulation to show that it influences the expression of hdpA in Xcc, but also expand knowledge of the function of the HDOD containing proteins in bacteria.
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Affiliation(s)
- Hsien-Ming Lee
- Institute of Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Yu-Yin Chang
- Institute of Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Yu-Tzu Yeh
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Shin-Chiao Du
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, 40601, Taiwan.
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30
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Liao CT, Liu YF, Chiang YC, Lo HH, Du SC, Hsu PC, Hsiao YM. Functional characterization and transcriptome analysis reveal multiple roles for prc in the pathogenicity of the black rot pathogen Xanthomonas campestris pv. campestris. Res Microbiol 2016; 167:299-312. [PMID: 26804425 DOI: 10.1016/j.resmic.2016.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 12/29/2015] [Accepted: 01/06/2016] [Indexed: 10/22/2022]
Abstract
Gram-negative phytopathogenic Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot in crucifers. The ability of Xcc to incite this disease in plants depends on a number of factors, including exopolysaccharides, extracellular enzymes and biofilm production. In this study, transposon mutagenesis led to identification of the prc gene, encoding a tail-specific protease, which plays a role in Xcc pathogenesis. Mutation of prc resulted in decreased virulence, extracellular protease production and bacterial attachment, with restoration to the levels of wild type by the intact prc gene. From subsequent quantitative RT-PCR analysis and reporter assay, the major extracellular protease gene prt1, biofilm-related gene galE encoding a UDP-galactose 4-epimerase and two putative adhesin genes (yapH and XC_4290 encoding autotransporter-like protein H and hemagglutinin, respectively) were found to be reduced in the prc mutant. Results of transcriptome profiling of Xcc wild type and prc mutant by RNA sequencing (RNA-Seq) showed that mutation of prc in Xcc leads to alteration in the transcriptional levels (more than twofold) of 91 genes. These differentially expressed genes were associated with a wide range of biological functions such as carbohydrate transport and metabolism, cell wall/membrane biogenesis, posttranslational modification, protein turnover and chaperones, inorganic ion transport and metabolism and signal transduction mechanisms. The results of this study facilitate the functional understanding of and provide new information about the regulatory role of prc.
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Affiliation(s)
- Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Yu-Fan Liu
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung 402, Taiwan.
| | - Ying-Chuan Chiang
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Hsueh-Hsia Lo
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Shin-Chiao Du
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Pei-Chi Hsu
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
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31
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Lau CKY, Krewulak KD, Vogel HJ. Bacterial ferrous iron transport: the Feo system. FEMS Microbiol Rev 2015; 40:273-98. [PMID: 26684538 DOI: 10.1093/femsre/fuv049] [Citation(s) in RCA: 212] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2015] [Indexed: 01/24/2023] Open
Abstract
To maintain iron homeostasis within the cell, bacteria have evolved various types of iron acquisition systems. Ferric iron (Fe(3+)) is the dominant species in an oxygenated environment, while ferrous iron (Fe(2+)) is more abundant under anaerobic conditions or at low pH. For organisms that must combat oxygen limitation for their everyday survival, pathways for the uptake of ferrous iron are essential. Several bacterial ferrous iron transport systems have been described; however, only the Feo system appears to be widely distributed and is exclusively dedicated to the transport of iron. In recent years, many studies have explored the role of the FeoB and FeoA proteins in ferrous iron transport and their contribution toward bacterial virulence. The three-dimensional structures for the Feo proteins have recently been determined and provide insight into the molecular details of the transport system. A highly select group of bacteria also express the FeoC protein from the same operon. This review will provide a comprehensive look at the structural and functional aspects of the Feo system. In addition, bioinformatics analyses of the feo operon and the Feo proteins have been performed to complement our understanding of this ubiquitous bacterial uptake system, providing a new outlook for future studies.
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Affiliation(s)
- Cheryl K Y Lau
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Karla D Krewulak
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Hans J Vogel
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
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32
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Zhang Y, Jalan N, Zhou X, Goss E, Jones JB, Setubal JC, Deng X, Wang N. Positive selection is the main driving force for evolution of citrus canker-causing Xanthomonas. THE ISME JOURNAL 2015; 9:2128-38. [PMID: 25689023 PMCID: PMC4579464 DOI: 10.1038/ismej.2015.15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/29/2014] [Accepted: 01/06/2015] [Indexed: 12/13/2022]
Abstract
Understanding the evolutionary history and potential of bacterial pathogens is critical to prevent the emergence of new infectious bacterial diseases. Xanthomonas axonopodis subsp. citri (Xac) (synonym X. citri subsp. citri), which causes citrus canker, is one of the hardest-fought plant bacterial pathogens in US history. Here, we sequenced 21 Xac strains (14 XacA, 3 XacA* and 4 XacA(w)) with different host ranges from North America and Asia and conducted comparative genomic and evolutionary analyses. Our analyses suggest that acquisition of beneficial genes and loss of detrimental genes most likely allowed XacA to infect a broader range of hosts as compared with XacA(w) and XacA*. Recombination was found to have occurred frequently on the relative ancient branches, but rarely on the young branches of the clonal genealogy. The ratio of recombination/mutation ρ/θ was 0.0790±0.0005, implying that the Xac population was clonal in structure. Positive selection has affected 14% (395 out of 2822) of core genes of the citrus canker-causing Xanthomonas. The genes affected are enriched in 'carbohydrate transport and metabolism' and 'DNA replication, recombination and repair' genes (P<0.05). Many genes related to virulence, especially genes involved in the type III secretion system and effectors, are affected by positive selection, further highlighting the contribution of positive selection to the evolution of citrus canker-causing Xanthomonas. Our results suggest that both metabolism and virulence genes provide advantages to endow XacA with higher virulence and a wider host range. Our analysis advances our understanding of the genomic basis of specialization by positive selection in bacterial evolution.
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Affiliation(s)
- Yunzeng Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
| | - Neha Jalan
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
| | - Xiaofeng Zhou
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
| | - Erica Goss
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, USA
| | - João C Setubal
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Xiaoling Deng
- Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL, USA
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Xanthomonas campestris pv. vesicatoria Secretes Proteases and Xylanases via the Xps Type II Secretion System and Outer Membrane Vesicles. J Bacteriol 2015; 197:2879-93. [PMID: 26124239 DOI: 10.1128/jb.00322-15] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 06/19/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Many plant-pathogenic bacteria utilize type II secretion (T2S) systems to secrete degradative enzymes into the extracellular milieu. T2S substrates presumably mediate the degradation of plant cell wall components during the host-pathogen interaction and thus promote bacterial virulence. Previously, the Xps-T2S system from Xanthomonas campestris pv. vesicatoria was shown to contribute to extracellular protease activity and the secretion of a virulence-associated xylanase. The identities and functions of additional T2S substrates from X. campestris pv. vesicatoria, however, are still unknown. In the present study, the analysis of 25 candidate proteins from X. campestris pv. vesicatoria led to the identification of two type II secreted predicted xylanases, a putative protease and a lipase which was previously identified as a virulence factor of X. campestris pv. vesicatoria. Studies with mutant strains revealed that the identified xylanases and the protease contribute to virulence and in planta growth of X. campestris pv. vesicatoria. When analyzed in the related pathogen X. campestris pv. campestris, several T2S substrates from X. campestris pv. vesicatoria were secreted independently of the T2S systems, presumably because of differences in the T2S substrate specificities of the two pathogens. Furthermore, in X. campestris pv. vesicatoria T2S mutants, secretion of T2S substrates was not completely absent, suggesting the contribution of additional transport systems to protein secretion. In line with this hypothesis, T2S substrates were detected in outer membrane vesicles, which were frequently observed for X. campestris pv. vesicatoria. We, therefore, propose that extracellular virulence-associated enzymes from X. campestris pv. vesicatoria are targeted to the Xps-T2S system and to outer membrane vesicles. IMPORTANCE The virulence of plant-pathogenic bacteria often depends on TS2 systems, which secrete degradative enzymes into the extracellular milieu. T2S substrates are being studied in several plant-pathogenic bacteria, including Xanthomonas campestris pv. vesicatoria, which causes bacterial spot disease in tomato and pepper. Here, we show that the T2S system from X. campestris pv. vesicatoria secretes virulence-associated xylanases, a predicted protease, and a lipase. Secretion assays with the related pathogen X. campestris pv. campestris revealed important differences in the T2S substrate specificities of the two pathogens. Furthermore, electron microscopy showed that T2S substrates from X. campestris pv. vesicatoria are targeted to outer membrane vesicles (OMVs). Our results, therefore, suggest that OMVs provide an alternative transport route for type II secreted extracellular enzymes.
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The galU gene of Xanthomonas campestris pv. campestris is involved in bacterial attachment, cell motility, polysaccharide synthesis, virulence, and tolerance to various stresses. Arch Microbiol 2014; 196:729-38. [DOI: 10.1007/s00203-014-1012-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 06/11/2014] [Accepted: 07/04/2014] [Indexed: 12/12/2022]
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Li CT, Liao CT, Du SC, Hsiao YP, Lo HH, Hsiao YM. Functional characterization and transcriptional analysis of galE gene encoding a UDP-galactose 4-epimerase in Xanthomonas campestris pv. campestris. Microbiol Res 2013; 169:441-52. [PMID: 24120348 DOI: 10.1016/j.micres.2013.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 08/12/2013] [Accepted: 08/24/2013] [Indexed: 11/29/2022]
Abstract
The Gram-negative plant pathogen Xanthomonas campestris pv. campestris (Xcc) is the causative agent of black rot in crucifers, a disease that causes tremendous agricultural loss. In this study, the Xcc galE gene was characterized. Sequence and mutational analysis demonstrated that the Xcc galE encodes a UDP-galactose 4-epimerase (EC 5.1.3.2), which catalyzes the interconversion of UDP-galactose and UDP-glucose. Alanine substitution of the putative catalytic residues (Ser124, Tyr147, and Lys151) of GalE caused loss of epimerase activity. Further study showed that the Xcc galE mutant had reduced biofilm formation ability. Furthermore, reporter assays revealed that galE transcription exhibits a distinct expression profile under different culture conditions, is subject to catabolite repression, and is positively regulated by Clp and RpfF. In addition, the galE transcription initiation site was mapped. This is the first time that UDP-galactose 4-epimerase has been characterized in the crucifer pathogen Xcc.
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Affiliation(s)
- Chien-Te Li
- Division of Chest Medicine, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan
| | - Chao-Tsai Liao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Shin-Chiao Du
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yu-Ping Hsiao
- Department of Dermatology, Chung Shan Medical University Hospital, Taichung, Taiwan; Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Hsueh-Hsia Lo
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
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Hausner J, Hartmann N, Lorenz C, Büttner D. The periplasmic HrpB1 protein from Xanthomonas spp. binds to peptidoglycan and to components of the type III secretion system. Appl Environ Microbiol 2013; 79:6312-24. [PMID: 23934485 PMCID: PMC3811196 DOI: 10.1128/aem.01226-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 07/31/2013] [Indexed: 11/20/2022] Open
Abstract
The plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria employs a type III secretion (T3S) system to translocate bacterial effector proteins into eukaryotic host cells. The membrane-spanning secretion apparatus consists of 11 core components and several associated proteins with yet unknown functions. In this study, we analyzed the role of HrpB1, which was previously shown to be essential for T3S and the formation of the extracellular T3S pilus. We provide experimental evidence that HrpB1 localizes to the bacterial periplasm and binds to peptidoglycan, which is in agreement with its predicted structural similarity to the putative peptidoglycan-binding domain of the lytic transglycosylase Slt70 from Escherichia coli. Interaction studies revealed that HrpB1 forms protein complexes and binds to T3S system components, including the inner membrane protein HrcD, the secretin HrcC, the pilus protein HrpE, and the putative inner rod protein HrpB2. The analysis of deletion and point mutant derivatives of HrpB1 led to the identification of amino acid residues that contribute to the interaction of HrpB1 with itself and HrcD and/or to protein function. The finding that HrpB1 and HrpB2 colocalize to the periplasm and both interact with HrcD suggests that they are part of a periplasmic substructure of the T3S system.
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Affiliation(s)
- Jens Hausner
- Institute of Biology, Department of Genetics, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
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Schmidtke C, Abendroth U, Brock J, Serrania J, Becker A, Bonas U. Small RNA sX13: a multifaceted regulator of virulence in the plant pathogen Xanthomonas. PLoS Pathog 2013; 9:e1003626. [PMID: 24068933 PMCID: PMC3771888 DOI: 10.1371/journal.ppat.1003626] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 08/01/2013] [Indexed: 01/12/2023] Open
Abstract
Small noncoding RNAs (sRNAs) are ubiquitous posttranscriptional regulators of gene expression. Using the model plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv), we investigated the highly expressed and conserved sRNA sX13 in detail. Deletion of sX13 impinged on Xcv virulence and the expression of genes encoding components and substrates of the Hrp type III secretion (T3S) system. qRT-PCR analyses revealed that sX13 promotes mRNA accumulation of HrpX, a key regulator of the T3S system, whereas the mRNA level of the master regulator HrpG was unaffected. Complementation studies suggest that sX13 acts upstream of HrpG. Microarray analyses identified 63 sX13-regulated genes, which are involved in signal transduction, motility, transcriptional and posttranscriptional regulation and virulence. Structure analyses of in vitro transcribed sX13 revealed a structure with three stable stems and three apical C-rich loops. A computational search for putative regulatory motifs revealed that sX13-repressed mRNAs predominantly harbor G-rich motifs in proximity of translation start sites. Mutation of sX13 loops differentially affected Xcv virulence and the mRNA abundance of putative targets. Using a GFP-based reporter system, we demonstrated that sX13-mediated repression of protein synthesis requires both the C-rich motifs in sX13 and G-rich motifs in potential target mRNAs. Although the RNA-binding protein Hfq was dispensable for sX13 activity, the hfq mRNA and Hfq::GFP abundance were negatively regulated by sX13. In addition, we found that G-rich motifs in sX13-repressed mRNAs can serve as translational enhancers and are located at the ribosome-binding site in 5% of all protein-coding Xcv genes. Our study revealed that sX13 represents a novel class of virulence regulators and provides insights into sRNA-mediated modulation of adaptive processes in the plant pathogen Xanthomonas. Since the discovery of the first regulatory RNA in 1981, hundreds of small RNAs (sRNAs) have been identified in bacteria. Although sRNA-mediated control of virulence was demonstrated for numerous animal- and human-pathogenic bacteria, sRNAs and their functions in plant-pathogenic bacteria have been enigmatic. We discovered that the sRNA sX13 is a novel virulence regulator of Xanthomonas campestris pv. vesicatoria (Xcv), which causes bacterial spot disease on pepper and tomato. sX13 contributes to the Xcv-plant interaction by promoting the synthesis of an essential pathogenicity factor of Xcv, i. e., the type III secretion system. Thus, in addition to transcriptional regulation, sRNA-mediated posttranscriptional regulation contributes to virulence of plant-pathogenic xanthomonads. To repress target mRNAs carrying G-rich motifs, sX13 employs C-rich loops. Hence, sX13 exhibits striking structural similarity to sRNAs in distantly related human pathogens, e. g., Staphylococcus aureus and Helicobacter pylori, suggesting that structure-driven target regulation via C-rich motifs represents a conserved feature of sRNA-mediated posttranscriptional regulation. Furthermore, sX13 is the first sRNA shown to control the mRNA level of hfq, which encodes a conserved RNA-binding protein required for sRNA activity and virulence in many enteric bacteria.
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Affiliation(s)
- Cornelius Schmidtke
- Institute for Biology, Department of Genetics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
- * E-mail: (CS); (UB)
| | - Ulrike Abendroth
- Institute for Biology, Department of Genetics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Juliane Brock
- Institute for Biology, Department of Genetics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Javier Serrania
- Loewe Center for Synthetic Microbiology and Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Anke Becker
- Loewe Center for Synthetic Microbiology and Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Ulla Bonas
- Institute for Biology, Department of Genetics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
- * E-mail: (CS); (UB)
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Jalan N, Kumar D, Andrade MO, Yu F, Jones JB, Graham JH, White FF, Setubal JC, Wang N. Comparative genomic and transcriptome analyses of pathotypes of Xanthomonas citri subsp. citri provide insights into mechanisms of bacterial virulence and host range. BMC Genomics 2013; 14:551. [PMID: 23941402 PMCID: PMC3751643 DOI: 10.1186/1471-2164-14-551] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 08/06/2013] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Citrus bacterial canker is a disease that has severe economic impact on citrus industries worldwide and is caused by a few species and pathotypes of Xanthomonas. X. citri subsp. citri strain 306 (XccA306) is a type A (Asiatic) strain with a wide host range, whereas its variant X. citri subsp. citri strain A(w)12879 (Xcaw12879, Wellington strain) is restricted to Mexican lime. RESULTS To characterize the mechanism for the differences in host range of XccA and Xcaw, the genome of Xcaw12879 that was completed recently was compared with XccA306 genome. Effectors xopAF and avrGf1 are present in Xcaw12879, but were absent in XccA306. AvrGf1 was shown previously for Xcaw to cause hypersensitive response in Duncan grapefruit. Mutation analysis of xopAF indicates that the gene contributes to Xcaw growth in Mexican lime but does not contribute to the limited host range of Xcaw. RNA-Seq analysis was conducted to compare the expression profiles of Xcaw12879 and XccA306 in Nutrient Broth (NB) medium and XVM2 medium, which induces hrp gene expression. Two hundred ninety two and 281 genes showed differential expression in XVM2 compared to in NB for XccA306 and Xcaw12879, respectively. Twenty-five type 3 secretion system genes were up-regulated in XVM2 for both XccA and Xcaw. Among the 4,370 common genes of Xcaw12879 compared to XccA306, 603 genes in NB and 450 genes in XVM2 conditions were differentially regulated. Xcaw12879 showed higher protease activity than XccA306 whereas Xcaw12879 showed lower pectate lyase activity in comparison to XccA306. CONCLUSIONS Comparative genomic analysis of XccA306 and Xcaw12879 identified strain specific genes. Our study indicated that AvrGf1 contributes to the host range limitation of Xcaw12879 whereas XopAF contributes to virulence. Transcriptome analyses of XccA306 and Xcaw12879 presented insights into the expression of the two closely related strains of X. citri subsp. citri. Virulence genes including genes encoding T3SS components and effectors are induced in XVM2 medium. Numerous genes with differential expression in Xcaw12879 and XccA306 were identified. This study provided the foundation to further characterize the mechanisms for virulence and host range of pathotypes of X. citri subsp. citri.
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Affiliation(s)
- Neha Jalan
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| | - Dibyendu Kumar
- Waksman Genomics Core Facility, Rutgers University Busch Campus, Piscataway, NJ 08854, USA
| | - Maxuel O Andrade
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| | - Fahong Yu
- ICBR, University of Florida, Gainesville, FL 32611, USA
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - James H Graham
- Department of Soil and Water Science, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| | - Frank F White
- Department of Plant Pathology, Kansas State University, 4024 Throckmorton Hall, Manhattan, KS 66506, USA
| | - João C Setubal
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060-0477, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
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Jalan N, Kumar D, Yu F, Jones JB, Graham JH, Wang N. Complete Genome Sequence of Xanthomonas citri subsp. citri Strain Aw12879, a Restricted-Host-Range Citrus Canker-Causing Bacterium. GENOME ANNOUNCEMENTS 2013; 1:e00235-13. [PMID: 23682143 PMCID: PMC3656205 DOI: 10.1128/genomea.00235-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 04/01/2013] [Indexed: 11/24/2022]
Abstract
Xanthomonas citri subsp. citri causes citrus canker. The Asiatic strain has a broad host range, whereas the Wellington variant has a restricted host range. Here, we present the complete genome of X. citri subsp. citri strain A(W)12879. This study lays the foundation to further characterize the mechanisms for virulence and host range of X. citri.
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Affiliation(s)
- Neha Jalan
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, Florida, USA
| | - Dibyendu Kumar
- Waksman Genomics Core Facility, Rutgers University, Busch Campus, Piscataway, New Jersey, USA
| | - Fahong Yu
- ICBR, University of Florida, Gainesville, Florida, USA
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - James H. Graham
- Citrus Research and Education Center, Department of Soil and Water Science, University of Florida, Lake Alfred, Florida, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, Florida, USA
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Liu W, Yu YH, Cao SY, Niu XN, Jiang W, Liu GF, Jiang BL, Tang DJ, Lu GT, He YQ, Tang JL. Transcriptome profiling of Xanthomonas campestris pv. campestris grown in minimal medium MMX and rich medium NYG. Res Microbiol 2013; 164:466-79. [PMID: 23470514 DOI: 10.1016/j.resmic.2013.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 02/14/2013] [Indexed: 12/14/2022]
Abstract
Xanthomonas campestris pathovar campestris (Xcc) is the causal agent of black rot disease in cruciferous plants worldwide. Although the complete genomes of several Xcc strains have been determined, the gene expression and regulation mechanisms in this pathogen are far from clear. In this work, transcriptome profiling of Xcc 8004 grown in MMX medium (minimal medium for Xanthomonas campestris) and NYG medium (peptone yeast glycerol medium) were investigated by RNA-Seq. Using the Illumina HiSeq 2000 platform, a total of 26,514,630 reads (90 nt in average) were generated, of which 15,708,478 reads mapped uniquely to coding regions of Xcc 8004 genome. Of the 4273 annotated protein-coding genes of Xcc 8004, 629 were found differentially expressed in Xcc grown in MMX and NYG. Of the differentially expressed genes, 495 were up-regulated and 134 were down-regulated in MMX. The MMX-induced genes are mainly involved in amino acid metabolism, transport systems, atypical condition adaptation and pathogenicity, especially the type III secretion system, while the MMX-repressed genes are mainly involved in chemotaxis and degradation of small molecules. The global transcriptome analyzes of Xcc 8004 grown in MMX and NYG might facilitate the gene functional characterization of this phytopathogenic bacterium.
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Affiliation(s)
- Wei Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi 530004, China
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Liu YF, Liao CT, Song WL, Hsu PC, Du SC, Lo HH, Hsiao YM. GsmR, a response regulator with an HD-related output domain in Xanthomonas campestris, is positively controlled by Clp and is involved in the expression of genes responsible for flagellum synthesis. FEBS J 2012; 280:199-213. [PMID: 23137357 DOI: 10.1111/febs.12061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 10/31/2012] [Accepted: 11/06/2012] [Indexed: 11/29/2022]
Abstract
In prokaryotes, two-component signal transduction systems, consisting of a histidine kinase and a response regulator, play a critical role in regulating a range of cellular functions. A recent study suggests that XCC3315, a response regulator with a CheY-like receiver domain attached to an uncharacterized HD-related output domain (HDOD domain), plays a role in the general stress response of the Gram-negative bacterium Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot in cruciferous plants. Here, we demonstrated genetically that XCC3315, designated as gsmR (general stress and motility regulator), is involved in the expression of genes responsible for flagellum synthesis, including rpoN2, flhF, flhB, and fliC. Site-directed mutagenesis revealed that Glu9 and Arg100 in the receiver domain and Gly205, Asp263, His287, Trp298 and His311 in the HDOD are critical amino acids for GsmR function in cell motility regulation. The gsmR transcription initiation site was mapped. Promoter analysis and gel retardation assay revealed that the expression of gsmR is positively controlled by the global transcriptional regulator Clp in a direct manner, and is subject to catabolite repression. Our findings not only extend the previous work on Clp regulation to show that it influences the expression of gsmR in Xcc, but are also the first to characterize the expression of this response regulator gene in this phytopathogen. Furthermore, GsmR is the first HDOD-containing protein of bacteria in which key amino acids have been experimentally identified and characterized.
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Affiliation(s)
- Yu-Fan Liu
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
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Jalan N, Aritua V, Kumar D, Yu F, Jones JB, Graham JH, Setubal JC, Wang N. Comparative genomic analysis of Xanthomonas axonopodis pv. citrumelo F1, which causes citrus bacterial spot disease, and related strains provides insights into virulence and host specificity. J Bacteriol 2011; 193:6342-57. [PMID: 21908674 PMCID: PMC3209208 DOI: 10.1128/jb.05777-11] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 08/30/2011] [Indexed: 11/20/2022] Open
Abstract
Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity.
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Affiliation(s)
- Neha Jalan
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida 33850
| | - Valente Aritua
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida 33850
| | - Dibyendu Kumar
- Interdisciplinary Center for Biotechnology Research, 2033 Mowry Road, University of Florida, Gainesville, Florida 32611
| | - Fahong Yu
- Interdisciplinary Center for Biotechnology Research, 2033 Mowry Road, University of Florida, Gainesville, Florida 32611
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, Florida 32611
| | - James H. Graham
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida 33850
| | - João C. Setubal
- Virginia Bioinformatics Institute and Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060-0477
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida 33850
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Hsiao YM, Song WL, Liao CT, Lin IH, Pan MY, Lin CF. Transcriptional analysis and functional characterization of XCC1294 gene encoding a GGDEF domain protein in Xanthomonas campestris pv. campestris. Arch Microbiol 2011; 194:293-304. [PMID: 22002465 DOI: 10.1007/s00203-011-0760-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/27/2011] [Accepted: 10/04/2011] [Indexed: 12/01/2022]
Abstract
The nucleotide cyclic di-GMP is a second messenger in bacteria that regulates a range of cellular functions including the virulence of pathogens. GGDEF is a protein domain involved in the synthesis of cyclic di-GMP. The genome of the crucifer pathogen Xanthomonas campestris pv. campestris (Xcc) encodes 21 proteins with a GGDEF domain. Clp, a homolog of the model transcription factor Crp of Escherichia coli, is a global regulator in Xcc. The aim of this study is to identify genes encoding GGDEF domain proteins whose expression is regulated by Clp. Results of reporter assay and RT-PCR analysis suggested that Clp regulates the expression of a set of genes encoding proteins harboring GGDEF domain. The transcription initiation site of XCC1294, one of the Clp regulated gene encoding a GGDEF domain protein, was mapped. Promoter analysis and gel retardation assay indicated that the transcription of XCC1294 is positively and directly regulated by Clp. Furthermore, transcription of XCC1294 was subject to catabolite repression and affected by several stress conditions. We also showed that mutation of XCC1294 results in enhanced surface attachment. In addition, transcription of three putative adhesin genes (xadA, fhaC, and yapH) was increased in the XCC1294 mutant. Taken together, the data presented here indicate that Clp positively regulates expression of XCC1294, and that XCC1294 serves a regulator of bacterial attachment and regulates different adhesin genes expression.
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Affiliation(s)
- Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
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Hsiao YM, Liu YF, Lee PY, Hsu PC, Tseng SY, Pan YC. Functional characterization of copA gene encoding multicopper oxidase in Xanthomonas campestris pv. campestris. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:9290-9302. [PMID: 21790191 DOI: 10.1021/jf2024006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The gram-negative plant pathogenic Xanthomonas campestris pv. campestris (Xcc) is the causative agent of black rot in crucifers, a disease causing tremendous loss in agriculture. Copper-containing bactericides have been widely used to control this disease for many years, possibly leading to the development of copper resistance in Xcc. Homologues of copper resistance genes copLAB are present in the Xcc genome, but none has been characterized. In this study, mutations in copL, copA, and copB decreased Xcc copper tolerance. Among them, the copA mutant displayed the most significant reduction. The copA mutant also resulted in a reduction in virulence on the host cabbage. Sequence and mutational analysis demonstrated that copA encodes a multicopper oxidase and that CopA is able to catalyze the oxidation of 2,6-dimethoxyphenol. Alanine substitutions in each of the putative copper binding residues (H538, H583, C584, and H585) of CopA caused a loss of function including copper tolerance and oxidase activity. Furthermore, reporter assays showed that copA transcription is inducible in the presence of copper, subject to catabolite repression, and repressed under conditions of high osmolarity, nitrogen starvation, or oxygen limitation. This is the first time that multicopper oxidase has been characterized in the crucifer pathogen Xcc.
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Affiliation(s)
- Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan.
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Guo Y, Figueiredo F, Jones J, Wang N. HrpG and HrpX play global roles in coordinating different virulence traits of Xanthomonas axonopodis pv. citri. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:649-61. [PMID: 21261465 DOI: 10.1094/mpmi-09-10-0209] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Xanthomonas axonopodis pv. citri is the causal agent of citrus canker, which is one of the most serious diseases of citrus. To understand the virulence mechanisms of X. axonopodis pv. citri, we designed and conducted genome-wide microarray analyses to characterize the HrpG and HrpX regulons, which are critical for the pathogenicity of X. axonopodis pv. citri. Our analyses revealed that 232 and 181 genes belonged to the HrpG and HrpX regulons, respectively. In total, 123 genes were overlapped in the two regulons at any of the three selected timepoints representing three growth stages of X. axonopodis pv. citri in XVM2 medium. Our results showed that HrpG and HrpX regulated all 24 type III secretion system genes, 23 type III secretion system effector genes, and 29 type II secretion system substrate genes. Our data revealed that X. axonopodis pv. citri regulates multiple cellular activities responding to the host environment, such as amino acid biosynthesis; oxidative phosphorylation; pentose-phosphate pathway; transport of sugar, iron, and potassium; and phenolic catabolism, through HrpX and HrpG. We found that 124 and 90 unknown genes were controlled by HrpG and HrpX, respectively. Our results suggest that HrpG and HrpX interplay with a global signaling network and co-ordinate the expression of multiple virulence factors for modification and adaption of host environment during X. axonopodis pv. citri infection.
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Affiliation(s)
- Yinping Guo
- Department of Microbiology and Cell Sciences, University of Florida, Lake Alfred, FL, USA
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Hsiao YM, Liu YF, Fang MC, Song WL. XCC2731, a GGDEF domain protein in Xanthomonas campestris, is involved in bacterial attachment and is positively regulated by Clp. Microbiol Res 2011; 166:548-65. [PMID: 21237626 DOI: 10.1016/j.micres.2010.11.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 11/17/2010] [Accepted: 11/18/2010] [Indexed: 10/18/2022]
Abstract
In Xanthomonas campestris pv. campestris (Xcc), which is the causative agent of black rot in crucifers, the virulence factor level is substantially decreased in the mutant deficient in RpfG, a phosphodiesterase that degrades the second messenger cyclic di-GMP. The rpfG mutant also grew in an aggregated state. It is indicated that expression of Pseudomonas GGDEF domain protein WspR (a diguanylate cyclase that synthesizes cyclic di-GMP) in wild-type Xcc can produce a phenocopy of the rpfG mutant. In this study, we showed that over-expression of GGDEF domain protein XCC2731 in wild-type Xcc caused (i) aggregation of cells, (ii) reduction in motility, and (iii) decrease in production of virulence factor extracellular enzymes and exopolysaccharides. Site-directed mutagenesis of the conserved G, G, and E residues of the GGDEF domain in XCC2731 abolished its function. The XCC2731 mutant has attenuated virulence. Furthermore, XCC2731 mutant was affected in surface attachment. Using the 5' RACE method, the XCC2731 transcription initiation site was mapped at nucleotide G, 15nt upstream of the XCC2731 start codon. Transcriptional fusion assay and gel retardation analysis indicated that Clp (cAMP receptor protein-like protein) positively regulates XCC2731 transcription in a direct manner. Reporter analysis also revealed that XCC2731 transcription is subject to catabolite repression, and reduced under conditions of oxygen limitation and high osmolarity. Our findings not only extend previous work on Clp regulation to show that it influences the expression of XCC2731 in Xcc, but also are the first to characterize the GGDEF domain protein gene expression in this phytopathogen.
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Affiliation(s)
- Yi-Min Hsiao
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan, ROC.
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Transcriptional analysis of pmeA gene encoding a pectin methylesterase in Xanthomonas campestris pv. campestris. Res Microbiol 2010; 162:270-8. [PMID: 21187145 DOI: 10.1016/j.resmic.2010.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 10/14/2010] [Indexed: 11/21/2022]
Abstract
Exopolysaccharides and several extracellular enzymes of Xanthomonas campestris pv. campestris (Xcc), the causative agent of black rot in crucifers, are virulence determinants. It is known that Clp (cAMP receptor protein-like protein) and RpfF (an enoyl-CoA hydratase homologue required for the synthesis of the diffusible signal factor, DSF) regulate production of these factors. In this study, plate assay revealed that Xcc possesses pectin methylesterase activity and that its expression is controlled by Clp and RpfF. Mutational analysis has demonstrated that pmeA encodes a pectin methylesterase. Using the 5' RACE method, the pmeA transcription initiation site was mapped. Transcriptional fusion assays showed that pmeA transcription is positively regulated by Clp and RpfF, subject to catabolite repression which is independent of Clp or RpfF, and repressed under conditions of high osmolarity or oxygen limitation. This study not only extends previous work on Clp and RpfF regulation by showing that they both influence the expression of pmeA in Xcc, but also, for the first time, characterizes pectin methylesterase gene expression in Xanthomonas.
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Chen CH, Lin NT, Hsiao YM, Yang CY, Tseng YH. Two non-consensus Clp binding sites are involved in upregulation of the gum operon involved in xanthan polysaccharide synthesis in Xanthomonas campestris pv. campestris. Res Microbiol 2010; 161:583-9. [DOI: 10.1016/j.resmic.2010.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Revised: 05/19/2010] [Accepted: 05/20/2010] [Indexed: 11/27/2022]
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Chen YY, Wu CH, Lin JW, Weng SF, Tseng YH. Mutation of the gene encoding a major outer-membrane protein in Xanthomonas campestris pv. campestris causes pleiotropic effects, including loss of pathogenicity. MICROBIOLOGY-SGM 2010; 156:2842-2854. [PMID: 20522496 DOI: 10.1099/mic.0.039420-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Xanthomonas campestris pv. campestris (Xcc) is the phytopathogen that causes black rot in crucifers. The xanthan polysaccharide and extracellular enzymes produced by this organism are virulence factors, the expression of which is upregulated by Clp (CRP-like protein) and DSF (diffusible signal factor), which is synthesized by RpfF. It is also known that biofilm formation/dispersal, regulated by the effect of controlled synthesis of DSF on cell-cell signalling, is required for virulence. Furthermore, a deficiency in DSF causes cell aggregation with concomitant production of a gum-like substance that can be dispersed by addition of DSF or digested by exogenous endo-beta-1,4-mannanase expressed by Xcc. In this study, Western blotting of proteins from a mopB mutant (XcMopB) showed Xcc MopB to be the major outer-membrane protein (OMP); Xcc MopB shared over 97 % identity with homologues from other members of Xanthomonas. Similarly to the rpfF mutant, XcMopB formed aggregates with simultaneous production of a gummy substance, but these aggregates could not be dispersed by DSF or endo-beta-1,4-mannanase, indicating that different mechanisms were involved in aggregation. In addition, XcMopB showed surface deformation, altered OMP composition, impaired xanthan production, increased sensitivity to stressful conditions including SDS, elevated temperature and changes in pH, reduced adhesion and motility and defects in pathogenesis. The finding that the major OMP is required for pathogenicity is unprecedented in phytopathogenic bacteria.
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Affiliation(s)
- Yih-Yuan Chen
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Chieh-Hao Wu
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Juey-Wen Lin
- Institute of Biochemistry, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Shu-Fen Weng
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Yi-Hsiung Tseng
- Institute of Microbiology, Immunology and Molecular Medicine, Tzu Chi University, Hualien 907, Taiwan, ROC
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Role of the FeoB protein and siderophore in promoting virulence of Xanthomonas oryzae pv. oryzae on rice. J Bacteriol 2010; 192:3187-203. [PMID: 20382771 DOI: 10.1128/jb.01558-09] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Xanthomonas oryzae pv. oryzae causes bacterial blight, a serious disease of rice. Our analysis revealed that the X. oryzae pv. oryzae genome encodes genes responsible for iron uptake through FeoB (homolog of the major bacterial ferrous iron transporter) and a siderophore. A mutation in the X. oryzae pv. oryzae feoB gene causes severe virulence deficiency, growth deficiency in iron-limiting medium, and constitutive production of a siderophore. We identified an iron regulated xss gene cluster, in which xssABCDE (Xanthomonas siderophore synthesis) and xsuA (Xanthomonas siderophore utilization) genes encode proteins involved in biosynthesis and utilization of X. oryzae pv. oryzae siderophore. Mutations in the xssA, xssB, and xssE genes cause siderophore deficiency and growth restriction under iron-limiting conditions but are virulence proficient. An xsuA mutant displayed impairment in utilization of native siderophore, suggesting that XsuA acts as a specific receptor for a ferric-siderophore complex. Histochemical and fluorimetric assays with gusA fusions indicate that, during in planta growth, the feoB gene is expressed and that the xss operon is not expressed. This study represents the first report describing a role for feoB in virulence of any plant-pathogenic bacterium and the first functional characterization of a siderophore-biosynthetic gene cluster in any xanthomonad.
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