1
|
Ramamoorthy S, Pena M, Ghosh P, Liao YY, Paret M, Jones JB, Potnis N. Transcriptome profiling of type VI secretion system core gene tssM mutant of Xanthomonas perforans highlights regulators controlling diverse functions ranging from virulence to metabolism. Microbiol Spectr 2024; 12:e0285223. [PMID: 38018859 PMCID: PMC10782981 DOI: 10.1128/spectrum.02852-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/20/2023] [Indexed: 11/30/2023] Open
Abstract
IMPORTANCE T6SS has received attention due to its significance in mediating interorganismal competition through contact-dependent release of effector molecules into prokaryotic and eukaryotic cells. Reverse-genetic studies have indicated the role of T6SS in virulence in a variety of plant pathogenic bacteria, including the one studied here, Xanthomonas. However, it is not clear whether such effect on virulence is merely due to a shift in the microbiome-mediated protection or if T6SS is involved in a complex virulence regulatory network. In this study, we conducted in vitro transcriptome profiling in minimal medium to decipher the signaling pathways regulated by tssM-i3* in X. perforans AL65. We show that TssM-i3* regulates the expression of a suite of genes associated with virulence and metabolism either directly or indirectly by altering the transcription of several regulators. These findings further expand our knowledge on the intricate molecular circuits regulated by T6SS in phytopathogenic bacteria.
Collapse
Affiliation(s)
- Sivakumar Ramamoorthy
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Michelle Pena
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Palash Ghosh
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Ying-Yu Liao
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Mathews Paret
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| |
Collapse
|
2
|
Bonfim IM, Paixão DA, Andrade MDO, Junior JM, Persinoti GF, de Giuseppe PO, Murakami MT. Plant structural and storage glucans trigger distinct transcriptional responses that modulate the motility of Xanthomonas pathogens. Microbiol Spectr 2023; 11:e0228023. [PMID: 37855631 PMCID: PMC10714752 DOI: 10.1128/spectrum.02280-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 09/05/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE Pathogenic Xanthomonas bacteria can affect a variety of economically relevant crops causing losses in productivity, limiting commercialization and requiring phytosanitary measures. These plant pathogens exhibit high level of host and tissue specificity through multiple molecular strategies including several secretion systems, effector proteins, and a broad repertoire of carbohydrate-active enzymes (CAZymes). Many of these CAZymes act on the plant cell wall and storage carbohydrates, such as cellulose and starch, releasing products used as nutrients and modulators of transcriptional responses to support host colonization by mechanisms yet poorly understood. Here, we reveal that structural and storage β-glucans from the plant cell function as spatial markers, providing distinct chemical stimuli that modulate the transition between higher and lower motility states in Xanthomonas citri, a key virulence trait for many bacterial pathogens.
Collapse
Affiliation(s)
- Isabela Mendes Bonfim
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), São Paulo, Brazil
- Graduate Program in Molecular and Morphofunctional Biology, Institute of Biology, University of Campinas, São Paulo, Brazil
| | - Douglas Alvarez Paixão
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), São Paulo, Brazil
| | - Maxuel de Oliveira Andrade
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), São Paulo, Brazil
| | - Joaquim Martins Junior
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), São Paulo, Brazil
| | - Gabriela Felix Persinoti
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), São Paulo, Brazil
| | - Priscila Oliveira de Giuseppe
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), São Paulo, Brazil
| | - Mário Tyago Murakami
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), São Paulo, Brazil
| |
Collapse
|
3
|
Wang H, Chen F, Tang G, Ke W, Wang S, Zheng D, Ruan L. A transcriptional Regulator Gar Regulates the Growth and Virulence of Xanthomonas oryzae pv. oryzae. Curr Microbiol 2023; 80:279. [PMID: 37436661 DOI: 10.1007/s00284-023-03396-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/28/2023] [Indexed: 07/13/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of bacterial blight, one of the most devastating diseases of rice. Pathogenic bacteria possess numerous transcriptional regulators to participate in the regulation of cellular processes. Here, we identified a transcriptional regulator Gar (PXO_RS11965) that is involved in regulating the growth and virulence of Xoo. Notably, the knockout of gar in Xoo enhanced bacterial virulence to the host rice. RNA-sequencing analysis and quantitative β-glucuronidase (GUS) assay indicated that Gar positively regulates the expression of a σ54 factor rpoN2. Further experiments confirmed that overexpression of rpoN2 restored the phenotypic changes caused by gar deletion. Our research revealed that Gar influences bacterial growth and virulence by positively regulating the expression of rpoN2.
Collapse
Affiliation(s)
- Huihui Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fan Chen
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Guiyu Tang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Wenli Ke
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shasha Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Dehong Zheng
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Agro-environment and Agro-product Safety, College of Agriculture, Guangxi University, Nanning, China
| | - Lifang Ruan
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
- College of Resources & Environment, Tibet Agriculture & Animal Husbandry University, Nyingchi, China.
| |
Collapse
|
4
|
Sena-Vélez M, Ferragud E, Redondo C, Graham JH, Cubero J. Chemotactic Responses of Xanthomonas with Different Host Ranges. Microorganisms 2022; 11:microorganisms11010043. [PMID: 36677335 PMCID: PMC9866238 DOI: 10.3390/microorganisms11010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/05/2022] [Accepted: 12/19/2022] [Indexed: 12/25/2022] Open
Abstract
Xanthomonas citri pv. citri (Xcc) (X. citri subsp. citri) type A is the causal agent of citrus bacterial canker (CBC) on most Citrus spp. and close relatives. Two narrow-host-range strains of Xcc, Aw and A*, from Florida and Southwest Asia, respectively, infect only Mexican lime (Citrus aurantifolia) and alemow (C. macrophylla). In the initial stage of infection, these xanthomonads enter via stomata to reach the apoplast. Herein, we investigated the differences in chemotactic responses for wide and narrow-host-range strains of Xcc A, X. euvesicatoria pv. citrumelonis (X. alfalfae subsp. citrumelonis), the causal agent of citrus bacterial spot, and X. campestris pv. campestris, the crucifer black rot pathogen. These strains of Xanthomonas were compared for carbon source use, the chemotactic responses toward carbon compounds, chemotaxis sensor content, and responses to apoplastic fluids from Citrus spp. and Chinese cabbage (Brassica pekinensis). Different chemotactic responses occurred for carbon sources and apoplastic fluids, depending on the Xanthomonas strain and the host plant from which the apoplastic fluid was derived. Differential chemotactic responses to carbon sources and citrus apoplasts suggest that these Xanthomonas strains sense host-specific signals that facilitate their location and entry of stomatal openings or wounds.
Collapse
Affiliation(s)
- Marta Sena-Vélez
- Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC) EA 1207, L’institut National de Recherche pour L’agriculture, L’alimentation et L’environneme (INRAE) USC1328, Orléans University, BP 6759, CEDEX 2, 45067 Orléans, France
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040 Madrid, Spain
| | - Elisa Ferragud
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040 Madrid, Spain
| | - Cristina Redondo
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040 Madrid, Spain
| | - James H. Graham
- Citrus Research and Education Center (CREC), University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850-2299, USA
| | - Jaime Cubero
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), 28040 Madrid, Spain
- Correspondence: ; Tel.: +34-913474162
| |
Collapse
|
5
|
Cai L, Ma W, Zou L, Xu X, Xu Z, Deng C, Qian W, Chen X, Chen G. Xanthomonas oryzae Pv. oryzicola Response Regulator VemR Is Co-opted by the Sensor Kinase CheA for Phosphorylation of Multiple Pathogenicity-Related Targets. Front Microbiol 2022; 13:928551. [PMID: 35756024 PMCID: PMC9218911 DOI: 10.3389/fmicb.2022.928551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Two-component systems (TCSs) (cognate sensor histidine kinase/response regulator pair, HK/RR) play a crucial role in bacterial adaptation, survival, and productive colonization. An atypical orphan single-domain RR VemR was characterized by the non-vascular pathogen Xanthomonas oryzae pv. oryzicola (Xoc) is known to cause bacterial leaf streak (BLS) disease in rice. Xoc growth and pathogenicity in rice, motility, biosynthesis of extracellular polysaccharide (EPS), and the ability to trigger HR in non-host tobacco were severely compromised in the deletion mutant strain RΔvemR as compared to the wild-type strain RS105. Site-directed mutagenesis and phosphotransfer experiments revealed that the conserved aspartate (D56) residue within the stand-alone phosphoacceptor receiver (REC) domain is essential for phosphorelay and the regulatory activity of Xoc VemR. Yeast two-hybrid (Y2H) and co-immunoprecipitation (co-IP) data identified CheA as the HK co-opting the RR VemR for phosphorylation. Affinity proteomics identified several downstream VemR-interacting proteins, such as 2-oxoglutarate dehydrogenase (OGDH), DNA-binding RR SirA, flagellar basal body P-ring formation protein FlgA, Type 4a pilus retraction ATPase PilT, stress-inducible sensor HK BaeS, septum site-determining protein MinD, cytoskeletal protein CcmA, and Type III and VI secretion system proteins HrpG and Hcp, respectively. Y2H and deletion mutant analyses corroborated that VemR interacted with OGDH, SirA, FlgA, and HrpG; thus, implicating multi-layered control of diverse cellular processes including carbon metabolism, motility, and pathogenicity in the rice. Physical interaction between VemR and HrpG suggested cross-talk interaction between CheA/VemR- and HpaS/HrpG-mediated signal transduction events orchestrating the hrp gene expression.
Collapse
Affiliation(s)
- Lulu Cai
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Wenxiu Ma
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Lifang Zou
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiameng Xu
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhengyin Xu
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Chaoying Deng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiaobin Chen
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- State Key Laboratory of Microbial Metabolism, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
6
|
Lin M, Wu K, Zhan Z, Mi D, Xia Y, Niu X, Feng S, Chen Y, He C, Tao J, Li C. The RavA/VemR two-component system plays vital regulatory roles in the motility and virulence of Xanthomonas campestris. MOLECULAR PLANT PATHOLOGY 2022; 23:355-369. [PMID: 34837306 PMCID: PMC8828458 DOI: 10.1111/mpp.13164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 05/08/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc) can cause black rot in cruciferous plants worldwide. Two-component systems (TCSs) are key for bacterial adaptation to various environments, including hosts. VemR is a TCS response regulator and crucial for Xcc motility and virulence. Here, we report that RavA is the cognate histidine kinase (HK) of VemR and elucidate the signalling pathway by which VemR regulates Xcc motility and virulence. Genetic analysis showed that VemR is epistatic to RavA. Using bacterial two-hybrid experiments and pull-down and phosphorylation assays, we found that RavA can interact with and phosphorylate VemR, suggesting that RavA is the cognate HK of VemR. In addition, we found that RpoN2 and FleQ are epistatic to VemR in regulating bacterial motility and virulence. In vivo and in vitro experiments demonstrated that VemR interacts with FleQ but not with RpoN2. RavA/VemR regulates the expression of the flagellin-encoding gene fliC by activating the transcription of the rpoN2-vemR-fleQ and flhF-fleN-fliA operons. In summary, our data show that the RavA/VemR TCS regulates FleQ activity and thus influences the expression of motility-related genes, thereby affecting Xcc motility and virulence. The identification of this novel signalling pathway will deepen our understanding of Xcc-plant interactions.
Collapse
Affiliation(s)
- Maojuan Lin
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Kejian Wu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Zhaohong Zhan
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Duo Mi
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Yingying Xia
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Xiaolei Niu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Shipeng Feng
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Yinhua Chen
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Jun Tao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| | - Chunxia Li
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical CropsHainan UniversityHaikouHainanChina
| |
Collapse
|
7
|
Zeng Z, Lin S, Li Q, Wang W, Wang Y, Xiao T, Guo Y. Molecular Basis of Wrinkled Variants Isolated From Pseudoalteromonas lipolytica Biofilms. Front Microbiol 2022; 13:797197. [PMID: 35295294 PMCID: PMC8919034 DOI: 10.3389/fmicb.2022.797197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Many Pseudoalteromonas species are dominant biofilm-forming Gammaproteobacteria in the ocean. The formation of Pseudoalteromonas biofilms is often accompanied by the occurrence of variants with different colony morphologies that may exhibit increased marine antifouling or anticorrosion activities. However, the genetic basis of the occurrence of these variants remains largely unexplored. In this study, we identified that wrinkled variants of P. lipolytica mainly arose due to mutations in the AT00_08765, a wspF-like gene, that are associated with decreased swimming motility and increased cellulose production. Moreover, we found that the spontaneous mutation in flhA, encoding a flagellar biosynthesis protein, also caused a wrinkled colony morphology that is associated with cellulose overproduction, indicating that flhA plays a dual role in controlling flagellar assembly and polysaccharide production in P. lipolytica. Investigation of wrinkled variants harboring spontaneous mutation in dgcB, encoding a GGDEF domain protein, also demonstrated dgcB plays an important role in regulating cellulose production and swimming motility. In addition, by screening the suppressor of the AT00_08765 variant strain, we also identified that the spontaneous mutation in cheR and bcsC directly abolished the wrinkled phenotype of the AT00_08765 variant strain, suggesting that the chemosensory signaling transduction and cellulose production are crucial for the determination of the wrinkled phenotype in P. lipolytica. Taken together, this study provides insights into the genetic variation within biofilms of P. lipolytica.
Collapse
Affiliation(s)
- Zhenshun Zeng
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China
| | - Shituan Lin
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qian Li
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China
| | - Weiquan Wang
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yuqi Wang
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China
| | - Tangfu Xiao
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China
- State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, China
| | - Yuexue Guo
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Yuexue Guo,
| |
Collapse
|
8
|
Two Flagellar mutants of Xanthomonas campestris are characterized by enhanced xanthan production and higher xanthan viscosity. J Biotechnol 2022; 347:9-17. [DOI: 10.1016/j.jbiotec.2022.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 02/04/2022] [Accepted: 02/08/2022] [Indexed: 11/20/2022]
|
9
|
Yu C, Yang F, Xue D, Wang X, Chen H. The Regulatory Functions of σ 54 Factor in Phytopathogenic Bacteria. Int J Mol Sci 2021; 22:ijms222312692. [PMID: 34884502 PMCID: PMC8657755 DOI: 10.3390/ijms222312692] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/16/2021] [Accepted: 11/22/2021] [Indexed: 12/24/2022] Open
Abstract
σ54 factor (RpoN), a type of transcriptional regulatory factor, is widely found in pathogenic bacteria. It binds to core RNA polymerase (RNAP) and regulates the transcription of many functional genes in an enhancer-binding protein (EBP)-dependent manner. σ54 has two conserved functional domains: the activator-interacting domain located at the N-terminal and the DNA-binding domain located at the C-terminal. RpoN directly binds to the highly conserved sequence, GGN10GC, at the −24/−12 position relative to the transcription start site of target genes. In general, bacteria contain one or two RpoNs but multiple EBPs. A single RpoN can bind to different EBPs in order to regulate various biological functions. Thus, the overlapping and unique regulatory pathways of two RpoNs and multiple EBP-dependent regulatory pathways form a complex regulatory network in bacteria. However, the regulatory role of RpoN and EBPs is still poorly understood in phytopathogenic bacteria, which cause economically important crop diseases and pose a serious threat to world food security. In this review, we summarize the current knowledge on the regulatory function of RpoN, including swimming motility, flagella synthesis, bacterial growth, type IV pilus (T4Ps), twitching motility, type III secretion system (T3SS), and virulence-associated phenotypes in phytopathogenic bacteria. These findings and knowledge prove the key regulatory role of RpoN in bacterial growth and pathogenesis, as well as lay the groundwork for further elucidation of the complex regulatory network of RpoN in bacteria.
Collapse
Affiliation(s)
- Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (C.Y.); (F.Y.)
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (C.Y.); (F.Y.)
| | - Dingrong Xue
- National Engineering Laboratory of Grain Storage and Logistics, Academy of National Food and Strategic Reserves Administration, No. 11 Baiwanzhuang Street, Xicheng District, Beijing 100037, China;
| | - Xiuna Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China;
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (C.Y.); (F.Y.)
- Correspondence:
| |
Collapse
|
10
|
Zhang Y, Andrade MO, Wang W, Teper D, Romeo T, Wang N. Examination of the Global Regulon of CsrA in Xanthomonas citri subsp. citri Using Quantitative Proteomics and Other Approaches. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1236-1249. [PMID: 34282945 DOI: 10.1094/mpmi-05-21-0113-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The RNA-binding protein CsrA is a global posttranscriptional regulator and controls many physiological processes and virulence traits. Deletion of csrA caused loss of virulence, reduced motility and production of xanthan gum and substantial increase in glycogen accumulation, as well as enhanced bacterial aggregation and cell adhesion in Xanthomonas spp. How CsrA controls these traits is poorly understood. In this study, an isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomic analysis was conducted to compare the protein profile of wild-type strain Xanthomonas citri subsp. citri and the isogenic ΔcsrA strain. A total of 2,374 proteins were identified, and 284 were considered to be differentially expressed proteins (DEPS), among which 151 proteins were up-regulated and 133 were down-regulated in the ΔcsrA strain with respect to the wild-type strain. Enrichment analysis and a protein-protein interaction network analysis showed that CsrA regulates bacterial secretion systems, flagella, and xanthan gum biosynthesis. Several proteins encoded by the gumB operon were down-regulated, whereas proteins associated with flagellum assembly and the type IV secretion system were up-regulated in the ΔcsrA strain relative to the Xcc306 strain. These results were confirmed by β-glucuronidase assay or Western blot. RNA secondary structure prediction and a gel-shift assay indicated that CsrA binds to the Shine-Dalgarno sequence of virB5. In addition, the iTRAQ analysis identified 248 DEPs that were not previously identified in transcriptome analyses. Among them, CsrA regulates levels of eight regulatory proteins (ColR, GacA, GlpR, KdgR, MoxR, PilH, RecX, and YgiX), seven TonB-dependent receptors, four outer membrane proteins, and two ferric enterobactin receptors. Taken together, this study greatly expands understanding of the regulatory network of CsrA in X. citri subsp. citri.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Collapse
Affiliation(s)
- Yanan Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
- Center for Yunnan Plateau Biological Resources Protection and Utilization, College of Biological Resource and Food Engineering, Qujing Normal University, Qujing, Yunnan, 655011, China
| | - Maxuel O Andrade
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Centre for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - Wenting Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
- Department of Plant Pathology, University of Florida, Gainesville FL 32611, U.S.A
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
| | - Tony Romeo
- Department of Microbiology and Cell Sciences, University of Florida, Gainesville FL 32611, U.S.A
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred FL 33850, U.S.A
| |
Collapse
|
11
|
Yu C, Nguyen DP, Yang F, Shi J, Wei Y, Tian F, Zhao X, Chen H. Transcriptome Analysis Revealed Overlapping and Special Regulatory Roles of RpoN1 and RpoN2 in Motility, Virulence, and Growth of Xanthomonas oryzae pv. oryzae. Front Microbiol 2021; 12:653354. [PMID: 33746934 PMCID: PMC7970052 DOI: 10.3389/fmicb.2021.653354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
σ54 factor (RpoN) plays a crucial role in bacterial motility, virulence, growth, and other biological functions. In our previous study, two homologous σ54 factors, RpoN1 and RpoN2, were identified in Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial leaf blight in rice. However, their functional roles, i.e., whether they exert combined or independent effects, remain unknown. In the current study, rpoN1 or rpoN2 deletion in Xoo significantly disrupted bacterial swimming motility, flagellar assembly, and virulence. Transcriptome analysis led to the identification of 127 overlapping differentially expressed genes (DEGs) regulated by both RpoN1 and RpoN2. Furthermore, GO and KEGG classification demonstrated that these DEGs were highly enriched in flagellar assembly, chemotaxis, and c-di-GMP pathways. Interestingly, ropN1 deletion decreased ropN2 transcription, while rpoN2 deletion did not affect ropN1 transcription. No interaction between the rpoN2 promoter and RpoN1 was detected, suggesting that RpoN1 indirectly regulates rpoN2 transcription. In addition, RpoN1-regulated DEGs were specially enriched in ribosome, carbon, and nitrogen metabolism pathways. Besides, bacterial growth was remarkably repressed in ΔrpoN1 but not in ΔrpoN2. Taken together, this study demonstrates the overlapping and unique regulatory roles of RpoN1 and RpoN2 in motility, virulence, growth and provides new insights into the regulatory mechanism of σ54 factors in Xoo.
Collapse
Affiliation(s)
- Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Doan-Phuong Nguyen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jia Shi
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yiming Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiuxiang Zhao
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
12
|
Decreased Biofilm Formation Ability of a Multidrug-Resistant Pseudomonas aeruginosa Strain After Exposure to a Simulated Microgravity Environment. Jundishapur J Microbiol 2021. [DOI: 10.5812/jjm.100465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: The refractory infection induced by multidrug-resistant (MDR) Pseudomonas aeruginosa has become one of the most urgent problems in hospitals. The biofilms formed by P. aeruginosa increase its resistance to antibiotics. A simulated microgravity (SMG) environment provides a platform to understand the factors affecting biofilm formation in bacteria. Objectives: This study aimed to investigate the SMG effects on MDR P. aeruginosa biofilm formation and explore the relevant mechanisms. Methods: In this study, a clinostat was used to simulate a microgravity (MG) environment. The motility and biofilm formation ability of MDR P. aeruginosa were observed using the swimming test and the crystal violet staining method, respectively. The underlying mechanism of phenotypic changes was further investigated by comparative transcriptomic analysis. Results: Multidrug-resistant P. aeruginosa grown under the SMG condition exhibited decreased swimming motility and biofilm formation ability compared to those under the normal gravity (NG) condition. Further analysis revealed that the decreased swimming motility and biofilm formation ability could be attributed to the downregulated expression of genes responsible for flagellar synthesis (flhB, fliQ, and fliR) and type IV pili biogenesis (pilDEXY1Y2VW). Conclusions: This is the first study to perform experiments on MDR P. aeruginosa under the SMG condition. It will be beneficial to understand the mechanism of MDR P. aeruginosa biofilm formation and develop new treatment strategies for infectious diseases induced by MDR P. aeruginosa in the future.
Collapse
|
13
|
An SQ, Potnis N, Dow M, Vorhölter FJ, He YQ, Becker A, Teper D, Li Y, Wang N, Bleris L, Tang JL. Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogen Xanthomonas. FEMS Microbiol Rev 2020; 44:1-32. [PMID: 31578554 PMCID: PMC8042644 DOI: 10.1093/femsre/fuz024] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/29/2019] [Indexed: 01/15/2023] Open
Abstract
Xanthomonas is a well-studied genus of bacterial plant pathogens whose members cause a variety of diseases in economically important crops worldwide. Genomic and functional studies of these phytopathogens have provided significant understanding of microbial-host interactions, bacterial virulence and host adaptation mechanisms including microbial ecology and epidemiology. In addition, several strains of Xanthomonas are important as producers of the extracellular polysaccharide, xanthan, used in the food and pharmaceutical industries. This polymer has also been implicated in several phases of the bacterial disease cycle. In this review, we summarise the current knowledge on the infection strategies and regulatory networks controlling virulence and adaptation mechanisms from Xanthomonas species and discuss the novel opportunities that this body of work has provided for disease control and plant health.
Collapse
Affiliation(s)
- Shi-Qi An
- National Biofilms Innovation Centre (NBIC), Biological Sciences, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Rouse Life Science Building, Auburn University, Auburn AL36849, USA
| | - Max Dow
- School of Microbiology, Food Science & Technology Building, University College Cork, Cork T12 K8AF, Ireland
| | | | - Yong-Qiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
| | - Anke Becker
- Loewe Center for Synthetic Microbiology and Department of Biology, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Yi Li
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Leonidas Bleris
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA.,Department of Biological Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX75080, USA
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
| |
Collapse
|
14
|
Li K, Wu G, Liao Y, Zeng Q, Wang H, Liu F. RpoN1 and RpoN2 play different regulatory roles in virulence traits, flagellar biosynthesis, and basal metabolism in Xanthomonas campestris. MOLECULAR PLANT PATHOLOGY 2020; 21:907-922. [PMID: 32281725 PMCID: PMC7280030 DOI: 10.1111/mpp.12938] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 05/08/2023]
Abstract
Homologous regulatory factors are widely present in bacteria, but whether homologous regulators synergistically or differentially regulate different biological functions remains mostly unknown. Here, we report that the homologous regulators RpoN1 and RpoN2 of the plant pathogen Xanthomonas campestris pv. campestris (Xcc) play different regulatory roles with respect to virulence traits, flagellar biosynthesis, and basal metabolism. RpoN2 directly regulated Xcc fliC and fliQ to modulate flagellar synthesis in X. campestris, thus affecting the swimming motility of X. campestris. Mutation of rpoN2 resulted in reduced production of biofilms and extracellular polysaccharides in Xcc. These defects may together cause reduced virulence of the rpoN2 mutant against the host plant. Moreover, we demonstrated that RpoN1 could regulate branched-chain fatty acid production and modulate the synthesis of diffusible signal factor family quorum sensing signals. Although RpoN1 and RpoN2 are homologues, the regulatory roles and biological functions of these proteins were not interchangeable. Overall, our report provides new insights into the two different molecular roles that form the basis for the transcriptional specialization of RpoN homologues.
Collapse
Affiliation(s)
- Kaihuai Li
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Guichun Wu
- Institute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjingChina
| | - Yuling Liao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouChina
| | - Quan Zeng
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew HavenCTUSA
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouChina
| | - Fengquan Liu
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
- Institute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjingChina
| |
Collapse
|
15
|
Qi YH, Huang L, Liu GF, Leng M, Lu GT. PilG and PilH antagonistically control flagellum-dependent and pili-dependent motility in the phytopathogen Xanthomonas campestris pv. campestris. BMC Microbiol 2020; 20:37. [PMID: 32070276 PMCID: PMC7029496 DOI: 10.1186/s12866-020-1712-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 01/27/2020] [Indexed: 12/27/2022] Open
Abstract
Background The virulence of the plant pathogen Xanthomonas campestris pv. campestris (Xcc) involves the coordinate expression of many virulence factors, including surface appendages flagellum and type IV pili, which are required for pathogenesis and the colonization of host tissues. Despite many insights gained on the structure and functions played by flagellum and pili in motility, biofilm formation, surface attachment and interactions with bacteriophages, we know little about how these appendages are regulated in Xcc. Results Here we present evidence demonstrating the role of two single domain response regulators PilG and PilH in the antagonistic control of flagellum-dependent (swimming) and pili-dependent (swarming) motility. Using informative mutagenesis, we reveal PilG positively regulates swimming motility while and negatively regulating swarming motility. Conversely, PilH negatively regulates swimming behaviour while and positively regulating swarming motility. By transcriptome analyses (RNA-seq and RT-PCR) we confirm these observations as PilG is shown to upregulate many genes involved chemotaxis and flagellar biosynthesis but these similar genes were downregulated by PilH. Co-immunoprecipitation, bacterial two-hybrid and pull-down analyses showed that PilH and PilG were able to interact with district subsets of proteins that potentially account for their regulatory impact. Additionally, we present evidence, using mutagenesis that PilG and PilH are involved in other cellular processes, including chemotaxis and virulence. Conclusions Taken together, we demonstrate that for the conditions tested PilG and PilH have inverse regulatory effects on flagellum-dependent and pili-dependent motility in Xcc and that this regulatory impact depends on these proteins influences on genes/proteins involved in flagellar biosynthesis and pilus assembly.
Collapse
Affiliation(s)
- Yan-Hua Qi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Li Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Guo-Fang Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Ming Leng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Guang-Tao Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China.
| |
Collapse
|
16
|
Schulte F, Leßmeier L, Voss J, Ortseifen V, Vorhölter FJ, Niehaus K. Regulatory associations between the metabolism of sulfur-containing amino acids and xanthan biosynthesis in Xanthomonas campestris pv. campestris B100. FEMS Microbiol Lett 2019; 366:5289864. [PMID: 30649298 DOI: 10.1093/femsle/fnz005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/14/2019] [Indexed: 02/06/2023] Open
Abstract
The γ-proteobacterium Xanthomonas campestris pv. campestris (Xcc) B100 synthesizes the exopolysaccharide xanthan, a commercially relevant thickening agent produced commonly by industrial scale fermentation. This work was inspired by the observation that methionine is an inhibitor of xanthan formation in growth experiments. Therefore, the global effects of methionine supplementation were characterized through cultivation experiments, genome-wide microarray hybridizations and qRT-PCR. Specific pull down of DNA-binding proteins by using the intergenic regions upstream of xanA, gumB and gumD led to the identification of six transcriptional regulators, among them the LysR-family transcriptional regulator CysB. An insertion mutant of this gene was analyzed by growth experiments, microarray experiments and qRT-PCR. Based on our experimental data, we developed a model that describes the methionine-dependent co-regulation of xanthan and sulfur-containing compounds in Xanthomonas. These data substantially contribute to better understand the impact of methionine as a compound in xanthan production media used in industrial fermentations.
Collapse
Affiliation(s)
- Fabian Schulte
- Department of Proteome and Metabolome Research - Bio27, Faculty of Biology, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Lennart Leßmeier
- Chair of Genetics of Prokaryotes, Faculty of Biology, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Julia Voss
- Department of Proteome and Metabolome Research - Bio27, Faculty of Biology, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Vera Ortseifen
- Department of Proteome and Metabolome Research - Bio27, Faculty of Biology, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Frank-Jörg Vorhölter
- Department of Proteome and Metabolome Research - Bio27, Faculty of Biology, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Karsten Niehaus
- Department of Proteome and Metabolome Research - Bio27, Faculty of Biology, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| |
Collapse
|
17
|
Conforte VP, Malamud F, Yaryura PM, Toum Terrones L, Torres PS, De Pino V, Chazarreta CN, Gudesblat GE, Castagnaro AP, R. Marano M, Vojnov AA. The histone-like protein HupB influences biofilm formation and virulence in Xanthomonas citri ssp. citri through the regulation of flagellar biosynthesis. MOLECULAR PLANT PATHOLOGY 2019; 20:589-598. [PMID: 30537413 PMCID: PMC6637892 DOI: 10.1111/mpp.12777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Citrus canker is an important disease of citrus, whose causal agent is the bacterium Xanthomonas citri ssp. citri (Xcc). In previous studies, we found a group of Xcc mutants, generated by the insertion of the Tn5 transposon, which showed impaired ability to attach to an abiotic substrate. One of these mutants carries the Tn5 insertion in hupB, a gene encoding a bacterial histone-like protein, homologue to the β-subunit of the Heat-Unstable (HU) nucleoid protein of Escherichia coli. These types of protein are necessary to maintain the bacterial nucleoid organization and the global regulation of gene expression. Here, we characterized the influence of the mutation in hupB regarding Xcc biofilm formation and virulence. The mutant strain hupB was incapable of swimming in soft agar, whereas its complemented strain partially recovered this phenotype. Electron microscope imaging revealed that impaired motility of hupB was a consequence of the absence of the flagellum. Comparison of the expression of flagellar genes between the wild-type strain and hupB showed that the mutant exhibited decreased expression of fliC (encoding flagellin). The hupB mutant also displayed reduced virulence compared with the wild-type strain when they were used to infect Citrus lemon plants using different infection methods. Our results therefore show that the histone-like protein HupB plays an essential role in the pathogenesis of Xcc through the regulation of biofilm formation and biosynthesis of the flagellum.
Collapse
Affiliation(s)
- Valeria P. Conforte
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| | - Florencia Malamud
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San MartínCampus Migueletes, 25 de Mayo y FranciaGeneral San MartínB1650HMN Provincia de Buenos AiresArgentina
| | - Pablo M. Yaryura
- Centro de Investigaciones y Transferencia de Villa María CONICETUniversidad de Villa MaríaCarlos Pellegrini 211Villa María, X5900FSECórdobaArgentina
| | - Laila Toum Terrones
- Departamento de FisiologíaBiología Molecular y Celular, Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresIntendente Güiraldes 2160Buenos AiresC1428EGAArgentina
| | - Pablo S. Torres
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| | - Verónica De Pino
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| | - Cristian N. Chazarreta
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| | - Gustavo E. Gudesblat
- Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA), Estación Experimental Agroindustrial Obispo Colombres (EEAOC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)Av. William Cross 3150Las TalitasC.P. T4101XACTucumánArgentina
| | - Atilio P. Castagnaro
- Departamento de FisiologíaBiología Molecular y Celular, Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresIntendente Güiraldes 2160Buenos AiresC1428EGAArgentina
| | - María R. Marano
- Instituto de Biología Molecular y Celular de Rosario, Departamento de Microbiología, Facultad de Ciencias, Bioquímicas y FarmacéuticasUniversidad Nacional de RosarioSuipacha 531RosarioS2002LRKSanta FéArgentina
| | - Adrian A. Vojnov
- Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICETSaladillo 2468Ciudad de Buenos AiresC1440FFXArgentina
| |
Collapse
|
18
|
Yang LY, Yang LC, Gan YL, Wang L, Zhao WZ, He YQ, Jiang W, Jiang BL, Tang JL. Systematic Functional Analysis of Sigma (σ) Factors in the Phytopathogen Xanthomonas campestris Reveals Novel Roles in the Regulation of Virulence and Viability. Front Microbiol 2018; 9:1749. [PMID: 30123197 PMCID: PMC6085468 DOI: 10.3389/fmicb.2018.01749] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/12/2018] [Indexed: 11/13/2022] Open
Abstract
The black rot pathogen Xanthomonas campestris pv. campestris (Xcc) is a model organism for the study of plant bacterial pathogenesis mechanisms. In bacteria, σ factors serve as important regulatory elements that respond to various environmental signals and cues. Though Xcc encodes 15 putative σ factors little is known about their roles. As an approach to identify the potential role of each σ factor, we constructed mutations in each of the σ-factor genes as well as generating mutants deficient in multiple σ factors to assess these regulators potential additive functions. The work identified two σ70 factors essential for growth. Furthermore, the work discovered a third σ70 factor, RpoE1, important for virulence. Further studies revealed that RpoE1 positively regulates the expression of the hrp gene cluster that encodes the type III secretion system (T3SS) which determines the pathogenicity and hypersensitive response of Xcc on plants. In vivo and in vitro studies demonstrated that RpoE1 could bind to the promoter region and promote transcription of hrpX, a gene encoding a key regulator of the hrp genes. Overall, this systematic analysis reveals important roles in Xcc survival and virulence for previously uncharacterized σ70 factors that may become important targets for disease control.
Collapse
Affiliation(s)
- Li-Yan Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Li-Chao Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yong-Liang Gan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Lin Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Wan-Zong Zhao
- Guangxi Key Laboratory of Power System Optimization and Energy Technology, Guangxi University, Nanning, China
| | - Yong-Qiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Wei Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Bo-Le Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| |
Collapse
|
19
|
Kan J, An L, Wu Y, Long J, Song L, Fang R, Jia Y. A dual role for proline iminopeptidase in the regulation of bacterial motility and host immunity. MOLECULAR PLANT PATHOLOGY 2018; 19:2011-2024. [PMID: 29517846 PMCID: PMC6638124 DOI: 10.1111/mpp.12677] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 03/06/2018] [Accepted: 03/06/2018] [Indexed: 05/07/2023]
Abstract
During plant-pathogen interactions, pathogenic bacteria have evolved multiple strategies to cope with the sophisticated defence systems of host plants. Proline iminopeptidase (PIP) is essential to Xanthomonas campestris pv. campestris (Xcc) virulence, and is conserved in many plant-associated bacteria, but its pathogenic mechanism remains unclear. In this study, we found that disruption of pip in Xcc enhanced its flagella-mediated bacterial motility by decreasing intracellular bis-(3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP) levels, whereas overexpression of pip in Xcc restricted its bacterial motility by elevating c-di-GMP levels. We also found that PIP is a type III secretion system-dependent effector capable of eliciting a hypersensitive response in non-host, but not host plants. When we transformed pip into the host plant Arabidopsis, higher bacterial titres were observed in pip-overexpressing plants relative to wild-type plants after Xcc inoculation. The repressive function of PIP on plant immunity was dependent on PIP's enzymatic activity and acted through interference with the salicylic acid (SA) biosynthetic and regulatory genes. Thus, PIP simultaneously regulates two distinct regulatory networks during plant-microbe interactions, i.e. it affects intracellular c-di-GMP levels to coordinate bacterial behaviour, such as motility, and functions as a type III effector translocated into plant cells to suppress plant immunity. Both processes provide bacteria with the regulatory potential to rapidly adapt to complex environments, to utilize limited resources for growth and survival in a cost-efficient manner and to improve the chances of bacterial survival by helping pathogens to inhabit the internal tissues of host plants.
Collapse
Affiliation(s)
- Jinhong Kan
- State Key Laboratory of Plant Genomics, Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China
- National Plant Gene Research CenterBeijing 100101China
- College of Life Sciences, University of the Chinese Academy of SciencesBeijing 100049China
- Present address:
Center for Crop Germplasm Resources, Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China
| | - Lin An
- State Key Laboratory of Plant Genomics, Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China
- National Plant Gene Research CenterBeijing 100101China
- College of Life Sciences, University of the Chinese Academy of SciencesBeijing 100049China
| | - Yao Wu
- State Key Laboratory of Plant Genomics, Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China
- National Plant Gene Research CenterBeijing 100101China
| | - Jia Long
- College of Life Sciences, Capital Normal UniversityBeijing 100048China
| | - Liyang Song
- State Key Laboratory of Plant Genomics, Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China
- National Plant Gene Research CenterBeijing 100101China
- College of Life Sciences, University of the Chinese Academy of SciencesBeijing 100049China
| | - Rongxiang Fang
- State Key Laboratory of Plant Genomics, Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China
- National Plant Gene Research CenterBeijing 100101China
| | - Yantao Jia
- State Key Laboratory of Plant Genomics, Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China
- National Plant Gene Research CenterBeijing 100101China
| |
Collapse
|
20
|
The Master Regulators of the Fla1 and Fla2 Flagella of Rhodobacter sphaeroides Control the Expression of Their Cognate CheY Proteins. J Bacteriol 2017; 199:JB.00670-16. [PMID: 27956523 DOI: 10.1128/jb.00670-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 12/06/2016] [Indexed: 11/20/2022] Open
Abstract
Rhodobacter sphaeroides is an alphaproteobacterium that has two complete sets of flagellar genes. The fla1 set was acquired by horizontal transfer from an ancestral gammaproteobacterium and is the only set of flagellar genes that is expressed during growth under standard laboratory conditions. The products of these genes assemble a single, subpolar flagellum. In the absence of the Fla1 flagellum, a gain-of-function mutation in the histidine kinase CckA turns on the expression of the fla2 flagellar genes through the response regulator CtrA. The rotation of the Fla1 and Fla2 flagella is controlled by different sets of chemotaxis proteins. Here, we show that the expression of the chemotaxis proteins that control Fla2, along with the expression of the fla2 genes, is coordinated by CtrA, whereas the expression of the chemotaxis genes that control Fla1 is mediated by the master regulators of the Fla1 system. The coordinated expression of the chemosensory proteins with their cognate flagellar genes highlights the relevance of integrating the expression of the horizontally acquired fla1 genes with a chemosensory system independently of the regulatory proteins responsible for the expression of fla2 and its cognate chemosensory system. IMPORTANCE Gene acquisition via horizontal transfer represents a challenge to the recipient organism to adjust its metabolic and genetic networks to incorporate the new material in a way that represents an adaptive advantage. In the case of Rhodobacter sphaeroides, a complete set of flagellar genes was acquired and successfully coordinated with the native flagellar system. Here we show that the expression of the chemosensory proteins that control flagellar rotation is dependent on the master regulators of their corresponding flagellar system, minimizing the use of transcription factors required to express the native and horizontally acquired genes along with their chemotaxis proteins.
Collapse
|
21
|
Song S, Xue Y, Liu E, Wang K, Zhang Y, Wu H, Zhang H. Comparative analysis of sigma factors RpoS, FliA, and RpoN in Edwardsiella tarda. Can J Microbiol 2016; 62:861-869. [DOI: 10.1139/cjm-2016-0158] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sigma factors are important regulators that bacteria employ to cope with environmental changes. Studies on the functions of sigma factors have uncovered their roles in many important cellular activities, such as growth, stress tolerance, motility, biofilm formation, and virulence. However, comparative analyses of sigma factors that examine their common and unique features or elucidate their cross-regulatory relationships have rarely been conducted for Edwardsiella tarda. Here, we characterized and compared motility and resistance to oxidative stress of E. tarda strains complemented with rpoS, fliA, and rpoN mutants. The results suggest that the sigma factors FliA and RpoN regulated motility, whereas RpoS exhibited no such function. RpoS and RpoN were essential for oxidative stress resistance, whereas FliA had no obvious impact under oxidative stress conditions. Furthermore, 2-dimensional gel electrophoresis based proteomics analysis combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry revealed 12 differentially expressed protein spots that represented 11 proteins between the mutant and wild-type strains. Quantification of the expression of target genes by quantitative reverse transcription PCR confirmed the results of our proteomics analysis. Collectively, these results suggest that these sigma factors are multifunctional mediators involved in controlling the expression of many metabolic pathway genes.
Collapse
Affiliation(s)
- ShanShan Song
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Yuanyuan Xue
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Enfu Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Keping Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Haizhen Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Huizhan Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| |
Collapse
|
22
|
FleQ coordinates flagellum-dependent and -independent motilities in Pseudomonas syringae pv. tomato DC3000. Appl Environ Microbiol 2015; 81:7533-45. [PMID: 26296726 DOI: 10.1128/aem.01798-15] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/14/2015] [Indexed: 12/29/2022] Open
Abstract
Motility plays an essential role in bacterial fitness and colonization in the plant environment, since it favors nutrient acquisition and avoidance of toxic substances, successful competition with other microorganisms, the ability to locate the preferred hosts, access to optimal sites within them, and dispersal in the environment during the course of transmission. In this work, we have observed that the mutation of the flagellar master regulatory gene, fleQ, alters bacterial surface motility and biosurfactant production, uncovering a new type of motility for Pseudomonas syringae pv. tomato DC3000 on semisolid surfaces. We present evidence that P. syringae pv. tomato DC3000 moves over semisolid surfaces by using at least two different types of motility, namely, swarming, which depends on the presence of flagella and syringafactin, a biosurfactant produced by this strain, and a flagellum-independent surface spreading or sliding, which also requires syringafactin. We also show that FleQ activates flagellum synthesis and negatively regulates syringafactin production in P. syringae pv. tomato DC3000. Finally, it was surprising to observe that mutants lacking flagella or syringafactin were as virulent as the wild type, and only the simultaneous loss of both flagella and syringafactin impairs the ability of P. syringae pv. tomato DC3000 to colonize tomato host plants and cause disease.
Collapse
|
23
|
Tian F, Yu C, Li H, Wu X, Li B, Chen H, Wu M, He C. Alternative sigma factor RpoN2 is required for flagellar motility and full virulence of Xanthomonas oryzae pv. oryzae. Microbiol Res 2015; 170:177-83. [DOI: 10.1016/j.micres.2014.07.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 07/04/2014] [Accepted: 07/21/2014] [Indexed: 10/25/2022]
|
24
|
Vladescu ID, Marsden EJ, Schwarz-Linek J, Martinez VA, Arlt J, Morozov AN, Marenduzzo D, Cates ME, Poon WCK. Filling an emulsion drop with motile bacteria. PHYSICAL REVIEW LETTERS 2014; 113:268101. [PMID: 25615389 DOI: 10.1103/physrevlett.113.268101] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Indexed: 06/04/2023]
Abstract
We have measured the spatial distribution of motile Escherichia coli inside spherical water droplets emulsified in oil. At low cell concentrations, the cell density peaks at the water-oil interface; at increasing concentration, the bulk of each droplet fills up uniformly while the surface peak remains. Simulations and theory show that the bulk density results from a "traffic" of cells leaving the surface layer, increasingly due to cell-cell scattering as the surface coverage rises above ∼10%. Our findings show similarities with the physics of a rarefied gas in a spherical cavity with attractive walls.
Collapse
Affiliation(s)
- I D Vladescu
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - E J Marsden
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - J Schwarz-Linek
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - V A Martinez
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - J Arlt
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - A N Morozov
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - D Marenduzzo
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - M E Cates
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - W C K Poon
- SUPA and The School of Physics & Astronomy, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| |
Collapse
|
25
|
Yaryura PM, Conforte VP, Malamud F, Roeschlin R, de Pino V, Castagnaro AP, McCarthy Y, Dow JM, Marano MR, Vojnov AA. XbmR, a new transcription factor involved in the regulation of chemotaxis, biofilm formation and virulence in Xanthomonas citri subsp. citri. Environ Microbiol 2014; 17:4164-76. [PMID: 25346091 DOI: 10.1111/1462-2920.12684] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 10/19/2014] [Indexed: 12/22/2022]
Abstract
Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus canker. Biofilm formation on citrus leaves plays an important role in epiphytic survival of Xcc. Biofilm formation is affected by transposon insertion in XAC3733, which encodes a transcriptional activator of the NtrC family, not linked to a gene encoding a sensor protein, thus could be considered as an 'orphan' regulator whose function is poorly understood in Xanthomonas spp. Here we show that mutation of XAC3733 (named xbmR) resulted in impaired structural development of the Xcc biofilm, loss of chemotaxis and reduced virulence in grapefruit plants. All defective phenotypes were restored to wild-type levels by the introduction of PA2567 from Pseudomonas aeruginosa, which encodes a phosphodiesterase active in the degradation of cyclic diguanosine monophosphate (c-di-GMP). A knockout of xbmR led to a substantial downregulation of fliA that encodes a σ(28) transcription factor, as well as fliC and XAC0350 which are potential member of the σ(28) regulon. XAC0350 encodes an HD-GYP domain c-di-GMP phosphodiesterase. These findings suggest that XbmR is a key regulator of flagellar-dependent motility and chemotaxis exerting its action through a regulatory pathway that involves FliA and c-di-GMP.
Collapse
Affiliation(s)
- Pablo M Yaryura
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Valeria P Conforte
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Florencia Malamud
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Roxana Roeschlin
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET). Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, S2000FHN, Rosario, Argentina
| | - Verónica de Pino
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Atilio P Castagnaro
- Estación Experimental Agroindustrial Obispo Colombres, Av. William Cross, 3150, Las Talitas, Tucumán, Argentina
| | - Yvonne McCarthy
- School of Microbiology, University College Cork, Cork, Ireland
| | - J Maxwell Dow
- School of Microbiology, University College Cork, Cork, Ireland
| | - María R Marano
- Instituto de Biología Molecular y Celular de Rosario (IBR)-Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET). Área Virología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, S2000FHN, Rosario, Argentina
| | - Adrián A Vojnov
- Instituto de Ciencia y Tecnología Dr. Cesar Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468, C1440FFX, Ciudad de Buenos Aires, Argentina
| |
Collapse
|
26
|
Moreira LM, Facincani AP, Ferreira CB, Ferreira RM, Ferro MIT, Gozzo FC, de Oliveira JCF, Ferro JA, Soares MR. Chemotactic signal transduction and phosphate metabolism as adaptive strategies during citrus canker induction by Xanthomonas citri. Funct Integr Genomics 2014; 15:197-210. [PMID: 25403594 DOI: 10.1007/s10142-014-0414-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 11/03/2014] [Accepted: 11/07/2014] [Indexed: 12/11/2022]
Abstract
The genome of Xanthomonas citri subsp. Citri strain 306 pathotype A (Xac) was completely sequenced more than 10 years; to date, few studies involving functional genomics Xac and its host compatible have been developed, specially related to adaptive events that allow the survival of Xac within the plant. Proteomic analysis of Xac showed that the processes of chemotactic signal transduction and phosphate metabolism are key adaptive strategies during the interaction of a pathogenic bacterium with its plant host. The results also indicate the importance of a group of proteins that may not be directly related to the classical virulence factors, but that are likely fundamental to the success of the initial stages of the infection, such as methyl-accepting chemotaxis protein (Mcp) and phosphate specific transport (Pst). Furthermore, the analysis of the mutant of the gene pstB which codifies to an ABC phosphate transporter subunit revealed a complete absence of citrus canker symptoms when inoculated in compatible hosts. We also conducted an in silico analysis which established the possible network of genes regulated by two-component systems PhoPQ and PhoBR (related to phosphate metabolism), and possible transcriptional factor binding site (TFBS) motifs of regulatory proteins PhoB and PhoP, detaching high degree of conservation of PhoB TFBS in 84 genes of Xac genome. This is the first time that chemotaxis signal transduction and phosphate metabolism were therefore indicated to be fundamental to the process of colonization of plant tissue during the induction of disease associated with Xanthomonas genus bacteria.
Collapse
Affiliation(s)
- Leandro Marcio Moreira
- Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Yang TC, Chen TF, Tsai JJ, Hu RM. NagZ is required for beta-lactamase expression and full pathogenicity in Xanthomonas campestris pv. campestris str. 17. Res Microbiol 2014; 165:612-9. [DOI: 10.1016/j.resmic.2014.08.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/21/2014] [Accepted: 08/22/2014] [Indexed: 01/17/2023]
|
28
|
Moser R, Aktas M, Narberhaus F. Phosphatidylcholine biosynthesis inXanthomonas campestrisvia a yeast-like acylation pathway. Mol Microbiol 2014; 91:736-50. [DOI: 10.1111/mmi.12492] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Roman Moser
- Microbial Biology; Ruhr University Bochum; Bochum Germany
| | - Meriyem Aktas
- Microbial Biology; Ruhr University Bochum; Bochum Germany
| | | |
Collapse
|
29
|
Prediction and characterization of protein-protein interaction network in Xanthomonas oryzae pv. oryzae PXO99 A. Res Microbiol 2013; 164:1035-44. [PMID: 24113387 DOI: 10.1016/j.resmic.2013.09.001] [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: 06/06/2013] [Accepted: 09/04/2013] [Indexed: 11/22/2022]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight disease in rice, is one of the most serious plant pathogens worldwide. In the current analysis, we constructed a protein-protein interaction network of Xoo strain PXO99(A) with two computational approaches (interolog method and domain combination method), and verified by K-Nearest Neighbors classification method. The predicted PPI network of Xoo PXO99(A) contains 36,886 interactions among 1988 proteins. KNN verification and GO annotation confirm the reliability of the network. Detailed analysis of flagellar synthesis and chemotaxis system shows that σ factors (especially σ(28), σ(54)) in Xoo PXO99(A) are very important for flagellar synthesis and motility, and transcription factors RpoA, RpoB and RpoC are hubs to connect most σ factors. Furthermore, Xoo PXO99(A) may have both cAMP and c-di-GMP signal transduction system, and the latter is especially important for this plant pathogen. This study therefore provides valuable clues to explore the pathogenicity and metabolic regulation of Xoo PXO99(A).
Collapse
|
30
|
González JF, Myers MP, Venturi V. The inter-kingdom solo OryR regulator of Xanthomonas oryzae is important for motility. MOLECULAR PLANT PATHOLOGY 2013; 14:211-21. [PMID: 23083431 PMCID: PMC6638885 DOI: 10.1111/j.1364-3703.2012.00843.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The LuxR-type transcriptional regulator OryR of the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo) is a member of a subgroup of regulators found in plant-associated bacteria that are known to respond to plant signals. OryR has been shown previously to positively regulate the neighbouring pip gene and to be important for rice virulence. The role of this inter-kingdom signalling regulator was investigated through a genome-wide transcriptome analysis. OryR was found to positively regulate 220 genes, whereas 110 were down-regulated. A significant over-representation of movement-related genes among the positively regulated ones was found, including 30 flagellar genes, accounting for 14% of the up-regulated genes above the two-fold cut-off value. In Xoo, both swimming and swarming respond to rice macerate and OryR plays a role in the induction of both of these types of motility under these conditions. In this study, we have also shown that the flagellar regulator flhF contains a lux box-like element in its promoter region, similar to the oryR-regulated neighbouring pip gene; via the use of a transcriptional fusion reporter, it was shown that flhF is regulated by OryR. Finally, the role of OryR in motility was also demonstrated by the significant reduction in flagellin content in the oryR Xoo mutant with respect to the wild-type, as observed by in planta proteomics studies.
Collapse
Affiliation(s)
- Juan F González
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | | |
Collapse
|
31
|
Yang TC, Chen TF, Tsai JJ, Hu RM. AmpG is required for BlaXcbeta-lactamase expression inXanthomonas campestrispv. campestris str. 17. FEMS Microbiol Lett 2013; 340:101-8. [DOI: 10.1111/1574-6968.12071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 11/27/2022] Open
Affiliation(s)
- Tsuey-Ching Yang
- Department of Biotechnology and Laboratory Science in Medicine; National Yang-Ming University; Taipei; Taiwan
| | - Tzu-Fan Chen
- Department of Biotechnology; Asia University; Wufeng; Taichung; Taiwan
| | - Jeffrey J.P. Tsai
- Department of Biomedical Informatics; Asia University; Wufeng; Taichung; Taiwan
| | | |
Collapse
|
32
|
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.
Collapse
Affiliation(s)
- Yu-Fan Liu
- Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
| | | | | | | | | | | | | |
Collapse
|
33
|
Wang K, Liu E, Song S, Wang X, Zhu Y, Ye J, Zhang H. Characterization of Edwardsiella tarda rpoN: roles in σ70 family regulation, growth, stress adaption and virulence toward fish. Arch Microbiol 2012; 194:493-504. [DOI: 10.1007/s00203-011-0786-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 12/15/2011] [Accepted: 12/23/2011] [Indexed: 12/26/2022]
|
34
|
Yang TC, Tsai MJ, Tsai JJ, Hu RM. Induction of a secretable beta-lactamase requires a long lag time in Xanthomonas campestris pv. campestris str. 17. Res Microbiol 2011; 162:999-1005. [DOI: 10.1016/j.resmic.2011.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 08/17/2011] [Indexed: 11/29/2022]
|
35
|
Deletion of σ(54) (rpoN) alters the rate of autolysis and biofilm formation in Enterococcus faecalis. J Bacteriol 2011; 194:368-75. [PMID: 22081387 DOI: 10.1128/jb.06046-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcription initiation is a critical step in bacterial gene regulation and is often controlled by transcription regulators. The alternate sigma factor (σ(54)) is one such regulator that facilitates activator-dependent transcription initiation and thus modulates the expression of a variety of genes involved in metabolism and pathogenesis in bacteria. This study describes the role of σ(54) in the nosocomial pathogen Enterococcus faecalis. Biofilm formation is one of the important pathogenic mechanisms of E. faecalis, as it elevates the organism's potential to cause surgical site and urinary tract infections. Lysis of bacterial cells within the population contributes to biofilm formation by providing extracellular DNA (eDNA) as a key component of the biofilm matrix. Deletion of rpoN rendered E. faecalis resistant to autolysis, which in turn impaired eDNA release. Despite the significant reduction in eDNA levels compared to the parental strain, the rpoN mutant formed more robust biofilms as observed using laser scanning confocal microscopy and Comstat analysis, indicating and emphasizing the presence of other matrix components. Initial adherence to a polystyrene surface was also enhanced in the mutant. Proteinase K treatment at early stages of biofilm development significantly reduced the accumulation of biofilm by the rpoN mutant. In conclusion, our data indicate that other factors in addition to eDNA might contribute to the overall composition of the enterococcal biofilm and that the regulatory role of σ(54) governs the nature and composition of the biofilm matrix.
Collapse
|
36
|
Francke C, Groot Kormelink T, Hagemeijer Y, Overmars L, Sluijter V, Moezelaar R, Siezen RJ. Comparative analyses imply that the enigmatic Sigma factor 54 is a central controller of the bacterial exterior. BMC Genomics 2011; 12:385. [PMID: 21806785 PMCID: PMC3162934 DOI: 10.1186/1471-2164-12-385] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 08/01/2011] [Indexed: 02/06/2023] Open
Abstract
Background Sigma-54 is a central regulator in many pathogenic bacteria and has been linked to a multitude of cellular processes like nitrogen assimilation and important functional traits such as motility, virulence, and biofilm formation. Until now it has remained obscure whether these phenomena and the control by Sigma-54 share an underlying theme. Results We have uncovered the commonality by performing a range of comparative genome analyses. A) The presence of Sigma-54 and its associated activators was determined for all sequenced prokaryotes. We observed a phylum-dependent distribution that is suggestive of an evolutionary relationship between Sigma-54 and lipopolysaccharide and flagellar biosynthesis. B) All Sigma-54 activators were identified and annotated. The relation with phosphotransfer-mediated signaling (TCS and PTS) and the transport and assimilation of carboxylates and nitrogen containing metabolites was substantiated. C) The function annotations, that were represented within the genomic context of all genes encoding Sigma-54, its activators and its promoters, were analyzed for intra-phylum representation and inter-phylum conservation. Promoters were localized using a straightforward scoring strategy that was formulated to identify similar motifs. We found clear highly-represented and conserved genetic associations with genes that concern the transport and biosynthesis of the metabolic intermediates of exopolysaccharides, flagella, lipids, lipopolysaccharides, lipoproteins and peptidoglycan. Conclusion Our analyses directly implicate Sigma-54 as a central player in the control over the processes that involve the physical interaction of an organism with its environment like in the colonization of a host (virulence) or the formation of biofilm.
Collapse
Affiliation(s)
- Christof Francke
- TI Food and Nutrition, P,O,Box 557, 6700AN Wageningen, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
37
|
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.
Collapse
Affiliation(s)
- Yinping Guo
- Department of Microbiology and Cell Sciences, University of Florida, Lake Alfred, FL, USA
| | | | | | | |
Collapse
|
38
|
Dong T, Yu R, Schellhorn H. Antagonistic regulation of motility and transcriptome expression by RpoN and RpoS in Escherichia coli. Mol Microbiol 2010; 79:375-86. [PMID: 21219458 DOI: 10.1111/j.1365-2958.2010.07449.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Bacteria generally possess multiple σ factors that, based on structural and functional similarity, divide into two families: σ(70) and σ(N) . Many studies have revealed σ factor competition within the σ(70) family, while the competition between σ(N) and σ(70) families has yet to be fully explored. Here we report a global antagonistic effect on gene expression between two alternative σ factors, σ(N) (RpoN) and a σ(70) family protein σ(S) (RpoS). Mutations in rpoS and rpoN were found to inversely affect a number of cellular traits, such as the expression of flagellar genes, σ(N) -controlled growth on poor nitrogen sources, and σ(S) -directed expression of acid phosphatase AppA. Transcriptome analysis reveals that about 60% of genes in the RpoN regulon are under reciprocal RpoS control. Furthermore, loss of RpoN led to increased levels of RpoS, while RpoN levels were unaffected by the rpoS mutation. Expression of the flagellar σ(F) factor (FliA), another σ(70) family protein, is controlled positively by RpoN but negatively by RpoS. This positive control by RpoN is likely mediated through the flagellar regulator FlhDC, whose expression is RpoN-dependent. These findings unveil a complex regulatory interaction among σ(N) , σ(S) and σ(F) , which modulates motility, nitrogen utilization, stress response and many other cellular functions.
Collapse
Affiliation(s)
- Tao Dong
- Department of Biology, McMaster University, Hamilton, ON, L8S4K1 Canada
| | | | | |
Collapse
|
39
|
Insights into the extracytoplasmic stress response of Xanthomonas campestris pv. campestris: role and regulation of {sigma}E-dependent activity. J Bacteriol 2010; 193:246-64. [PMID: 20971899 DOI: 10.1128/jb.00884-10] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Xanthomonas campestris pv. campestris is an epiphytic bacterium that can become a vascular pathogen responsible for black rot disease of crucifers. To adapt gene expression in response to ever-changing habitats, phytopathogenic bacteria have evolved signal transduction regulatory pathways, such as extracytoplasmic function (ECF) σ factors. The alternative sigma factor σ(E), encoded by rpoE, is crucial for envelope stress response and plays a role in the pathogenicity of many bacterial species. Here, we combine different approaches to investigate the role and mechanism of σ(E)-dependent activation in X. campestris pv. campestris. We show that the rpoE gene is organized as a single transcription unit with the anti-σ gene rseA and the protease gene mucD and that rpoE transcription is autoregulated. rseA and mucD transcription is also controlled by a highly conserved σ(E)-dependent promoter within the σ(E) gene sequence. The σ(E)-mediated stress response is required for stationary-phase survival, resistance to cadmium, and adaptation to membrane-perturbing stresses (elevated temperature and ethanol). Using microarray technology, we started to define the σ(E) regulon of X. campestris pv. campestris. These genes encode proteins belonging to different classes, including periplasmic or membrane proteins, biosynthetic enzymes, classical heat shock proteins, and the heat stress σ factor σ(H). The consensus sequence for the predicted σ(E)-regulated promoter elements is GGAACTN(15-17)GTCNNA. Determination of the rpoH transcription start site revealed that rpoH was directly regulated by σ(E) under both normal and heat stress conditions. Finally, σ(E) activity is regulated by the putative regulated intramembrane proteolysis (RIP) proteases RseP and DegS, as previously described in many other bacteria. However, our data suggest that RseP and DegS are not only dedicated to RseA cleavage and that the proteolytic cascade of RseA could involve other proteases.
Collapse
|
40
|
Tao J, He C. Response regulator, VemR, positively regulates the virulence and adaptation of Xanthomonas campestris pv. campestris. FEMS Microbiol Lett 2010. [DOI: 10.1111/j.1574-6968.2009.01892.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
41
|
Tao J, He C. Response regulator, VemR, positively regulates the virulence and adaptation of Xanthomonas campestris pv. campestris. FEMS Microbiol Lett 2010; 304:20-8. [PMID: 20082640 DOI: 10.1111/j.1574-6968.2010.01892.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot disease in cruciferous plants. The synthesis of known virulence factors in this organism, such as extracellular enzymes and biofilm, is strictly regulated in response to environmental stimuli. Two-component signal transduction systems sense environmental signals and alter bacterial behavior by regulating gene expression. Here, we identified a response regulator, VemR, that regulates Xcc pathogenesis. The vemR gene encodes an atypical response regulator that only contains a receiver domain. Deletion of vemR resulted in decreased virulence, exopolysaccharide production and motility of Xcc. The vemR gene is located in an operon flanked by genes fleQ and rpoN2. Genetic analysis indicated that deletion of fleQ does not affect motility significantly. However, a double mutant DeltavemR/DeltafleQ reversed the phenotype of DeltavemR, indicating that fleQ is epistatic to vemR in the regulation of virulence and adaptation.
Collapse
Affiliation(s)
- Jun Tao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | | |
Collapse
|