1
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Huang J, Wang R, Zhang Q, Wang C, Liang T, Hikichi Y, Ohnishi K, Jiang G, Guo T, Zhang Y. Positive regulation of the PhcB neighbouring regulator PrhX on expression of the type III secretion system and pathogenesis in Ralstonia solanacearum. MOLECULAR PLANT PATHOLOGY 2024; 25:e13398. [PMID: 37877898 PMCID: PMC10788593 DOI: 10.1111/mpp.13398] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/04/2023] [Accepted: 10/04/2023] [Indexed: 10/26/2023]
Abstract
Ralstonia solanacearum PhcB and PhcA control a quorum-sensing (QS) system that globally regulates expression of about one third of all genes, including pathogenesis genes. The PhcB-PhcA QS system positively regulates the production of exopolysaccharide (EPS) and negatively regulates hrp gene expression, which is crucial for the type III secretion system (T3SS). Both EPS and the T3SS are essential for pathogenicity. The gene rsc2734 is located upstream of a phcBSR operon and annotated as a response regulator of a two-component system. Here, we demonstrated that RSc2734, hereafter named PrhX, positively regulated hrp gene expression via a PrhA-PrhIR-PrhJ-HrpG signalling cascade. Moreover, PrhX was crucial for R. solanacearum to invade host roots and grow in planta naturally. prhX expression was independent of the PhcB-PhcA QS system. PrhX did not affect the expression of phcB and phcA and the QS-dependent phenotypes, such as EPS production and biofilm formation. Our results provide novel insights into the complex regulatory network of the T3SS and pathogenesis in R. solanacearum.
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Affiliation(s)
- Jiajun Huang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Rongsheng Wang
- Liaoning Key Laboratory of Plant Pathology, College of Plant ProtectionShenyang Agricultural UniversityShenyangChina
| | - Qi Zhang
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Chunli Wang
- Chongqing Academy of Agricultural SciencesChongqingChina
| | - Tao Liang
- Chongqing Station of Agricultural Ecology and Resource ProtectionChongqingChina
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Gaofei Jiang
- National Engineering Research Center for Organic‐based FertilizersNanjing Agricultural UniversityNanjingChina
| | - Tao Guo
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River BasinSouthwest UniversityChongqingChina
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2
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Zhang Q, Wu B, Han L, Yu D, Liang T, Wang Y, Guo T. Functional characterization of two 3-dehydroquinases of AroQ1 and AroQ2 in the shikimate pathway and expression of genes for the type III secretion system in Ralstonia solanacearum. Front Microbiol 2023; 14:1186688. [PMID: 37180250 PMCID: PMC10171560 DOI: 10.3389/fmicb.2023.1186688] [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: 03/15/2023] [Accepted: 03/28/2023] [Indexed: 05/16/2023] Open
Abstract
The shikimate pathway is a general route for the biosynthesis of aromatic amino acids (AAAs) in many microorganisms. A 3-dehydroquinase, AroQ, controls the third step of the shikimate pathway that catalyzes the formation of 3-dehydroquinate from 3-dehydroshikimate via a trans-dehydration reaction. Ralstonia solanacearum harbors two 3-dehydroquinases, AroQ1 and AroQ2, sharing 52% similarity in amino acids. Here, we demonstrated that two 3-dehydroquinases, AroQ1 and AroQ2, are essential for the shikimate pathway in R. solanacearum. The growth of R. solanacearum was completely diminished in a nutriment-limited medium with the deletion of both aroQ1 and aroQ2, while substantially impaired in planta. The aroQ1/2 double mutant was able to replicate in planta but grew slowly, which was ~4 orders of magnitude less than the parent strain to proliferate to the maximum cell densities in tomato xylem vessels. Moreover, the aroQ1/2 double mutant failed to cause disease in tomato and tobacco plants, whereas the deletion of either aroQ1 or aroQ2 did not alter the growth of R. solanacearum or pathogenicity on host plants. Supplementary shikimic acid (SA), an important intermediate of the shikimate pathway, substantially restored the diminished or impaired growth of aroQ1/2 double mutant in a limited medium or inside host plants. The necessity of AroQ1 and AroQ2 on the pathogenicity of solanacearum toward host plants was partially due to insufficient SA inside host plants. Moreover, the deletion of both aroQ1 and aroQ2 significantly impaired the expression of genes for the type III secretion system (T3SS) both in vitro and in planta. Its involvement in the T3SS was mediated through the well-characterized PrhA signaling cascade and was independent of growth deficiency under nutrient-limited conditions. Taken together, R. solanacearum 3-dehydroquinases play important roles in bacterial growth, the expression of the T3SS, and pathogenicity in host plants. These results could extend our insights into the understanding of the biological function of AroQ and the sophisticated regulation of the T3SS in R. solanacearum.
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Affiliation(s)
- Qingshan Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Bofan Wu
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Liangliang Han
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Duan Yu
- Chongqing Academy of Agricultural Sciences, Chongqing, China
| | - Tao Liang
- Chongqing Academy of Agricultural Sciences, Chongqing, China
| | - Yan Wang
- Chongqing Academy of Agricultural Sciences, Chongqing, China
- *Correspondence: Yan Wang
| | - Tao Guo
- College of Resources and Environment, Southwest University, Chongqing, China
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Rivera-Zuluaga K, Hiles R, Barua P, Caldwell D, Iyer-Pascuzzi AS. Getting to the root of Ralstonia invasion. Semin Cell Dev Biol 2022; 148-149:3-12. [PMID: 36526528 DOI: 10.1016/j.semcdb.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/16/2022]
Abstract
Plant diseases caused by soilborne pathogens are a major limiting factor in crop production. Bacterial wilt disease, caused by soilborne bacteria in the Ralstonia solanacearum Species Complex (Ralstonia), results in significant crop loss throughout the world. Ralstonia invades root systems and colonizes plant xylem, changing plant physiology and ultimately causing plant wilting in susceptible varieties. Elucidating how Ralstonia invades and colonizes plants is central to developing strategies for crop protection. Here we review Ralstonia pathogenesis from root detection and attachment, early root colonization, xylem invasion and subsequent wilting. We focus primarily on studies in tomato from the last 5-10 years. Recent work has identified elegant mechanisms Ralstonia uses to adapt to the plant xylem, and has discovered new genes that function in Ralstonia fitness in planta. A picture is emerging of an amazingly versatile pathogen that uses multiple strategies to make its surrounding environment more hospitable and can adapt to new environments.
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Moussa Z, Rashad EM, Elsherbiny EA, Al-Askar AA, Arishi AA, Al-Otibi FO, Saber WIA. New Strategy for Inducing Resistance against Bacterial Wilt Disease Using an Avirulent Strain of Ralstonia solanacearum. Microorganisms 2022; 10:1814. [PMID: 36144416 PMCID: PMC9504442 DOI: 10.3390/microorganisms10091814] [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: 08/23/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
Ralstonia solanacearum is one of the globally significant plant pathogens that infect a wide host range of economically important plants. A study was conducted to evaluate the hypothesis that an avirulent strain of R. solanacearum can act as a biocontrol mediator for managing potato bacterial wilt. Virulent R. solanacearum was isolated and identified (GenBank accession number; OP180100). The avirulent strain was obtained from the virulent strain through storage for 3 weeks until the development of deep red colonies. The virulent strain had higher lytic activity than the avirulent strain. Tubers' treatments by the avirulent strain of R. solanacearum, (supernatant, boiled supernatant, and dead cells) significantly reduced plant disease rating and increased the growth, physiological activities, and biomass of potato compared to the untreated, infected control. The major components detected by GC-MS in the supernatant revealed 10.86% palmitic acid (virulent), and 18.03% 1,3-dioxolane, 2,4,5-trimethyl- (avirulent), whereas the major component in the boiled supernatant was 2-hydroxy-gamma-butyrolactone in the virulent (21.17%) and avirulent (27.78%) strains. This is the first research that assessed the influence of boiled supernatant and dead cells of virulent and avirulent R.solanacearum strains in controlling bacterial wilt disease. Additional work is encouraged for further elucidation of such a topic.
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Affiliation(s)
- Zeiad Moussa
- Microbial Activity Unit, Microbiology Department, Soils, Water and Environment Research Institute, Agricultural Research Center, Giza 12619, Egypt
| | - Ehsan M. Rashad
- Department of Seed Pathology Research, Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt
| | | | - Abdulaziz A. Al-Askar
- Department of Botany and Microbiology, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Amr Abker Arishi
- School of Molecular Sciences, The University of Western Australia, Perth, WA 6009, Australia
| | - Fatimah O. Al-Otibi
- Department of Botany and Microbiology, Faculty of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - WesamEldin I. A. Saber
- Microbial Activity Unit, Microbiology Department, Soils, Water and Environment Research Institute, Agricultural Research Center, Giza 12619, Egypt
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Guan Y, Wang R, Chen N, Zhu Y, Han L, Chen X, Li J, Zhang Y. Functional characterization of a gamma-glutamyl phosphate reductase ProA in proline biosynthesis and promoting expression of type three secretion system in Ralstonia solanacearum. Front Microbiol 2022; 13:945831. [PMID: 36106083 PMCID: PMC9465252 DOI: 10.3389/fmicb.2022.945831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 08/05/2022] [Indexed: 11/24/2022] Open
Abstract
Ralstonia solanacearum RSc2741 has been predicted as a gamma-glutamyl phosphate reductase ProA catalyzing the second reaction of proline formation from glutamate. Here, we experimentally demonstrated that proA mutants were proline auxotrophs that failed to grow in a minimal medium, and supplementary proline, but not glutamate, fully restored the diminished growth, confirming that ProA is responsible for the biosynthesis of proline from glutamate in R. solanacearum. ProA was previously identified as one of the candidates regulating the expression of genes for type three secretion system (T3SS), one of the essential pathogenicity determinants of R. solanacearum. Supplementary proline significantly enhanced the T3SS expression both in vitro and in planta, indicating that proline is a novel inducer of the T3SS expression. Deletion of proA substantially impaired the T3SS expression both in vitro and in planta even under proline-supplemented conditions, indicating that ProA plays additional roles apart from proline biosynthesis in promoting the expression of the T3SS genes. It was further revealed that the involvement of ProA in the T3SS expression was mediated through the pathway of PrhG-HrpB. Both the proA mutants and the wild-type strain grew in the intercellular spaces of tobacco leaves, while their ability to invade and colonize tobacco xylem vessels was substantially impaired, which was about a 1-day delay for proA mutants to successfully invade xylem vessels and was about one order of magnitude less than the wild-type strain to proliferate to the maximum densities in xylem vessels. It thus resulted in substantially impaired virulence of proA mutants toward host tobacco plants. The impaired abilities of proA mutants to invade and colonize xylem vessels were not due to possible proline insufficiency in the rhizosphere soil or inside the plants. All taken together, these results extend novel insights into the understanding of the biological function of ProA and sophisticated regulation of the T3SS and pathogenicity in R. solanacearum.
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Affiliation(s)
- Yue Guan
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Rongsheng Wang
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Nan Chen
- College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, China
| | - Yalan Zhu
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Liangliang Han
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Xinping Chen
- College of Resources and Environment, Southwest University, Chongqing, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Jing Li
- The Ninth People’s Hospital of Chongqing, Chongqing, China
- *Correspondence: Jing Li,
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
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Bullones-Bolaños A, Bernal-Bayard J, Ramos-Morales F. The NEL Family of Bacterial E3 Ubiquitin Ligases. Int J Mol Sci 2022; 23:7725. [PMID: 35887072 PMCID: PMC9320238 DOI: 10.3390/ijms23147725] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 12/16/2022] Open
Abstract
Some pathogenic or symbiotic Gram-negative bacteria can manipulate the ubiquitination system of the eukaryotic host cell using a variety of strategies. Members of the genera Salmonella, Shigella, Sinorhizobium, and Ralstonia, among others, express E3 ubiquitin ligases that belong to the NEL family. These bacteria use type III secretion systems to translocate these proteins into host cells, where they will find their targets. In this review, we first introduce type III secretion systems and the ubiquitination process and consider the various ways bacteria use to alter the ubiquitin ligation machinery. We then focus on the members of the NEL family, their expression, translocation, and subcellular localization in the host cell, and we review what is known about the structure of these proteins, their function in virulence or symbiosis, and their specific targets.
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Affiliation(s)
| | | | - Francisco Ramos-Morales
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain; (A.B.-B.); (J.B.-B.)
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Kashyap A, Jiménez-Jiménez ÁL, Zhang W, Capellades M, Srinivasan S, Laromaine A, Serra O, Figueras M, Rencoret J, Gutiérrez A, Valls M, Coll NS. Induced ligno-suberin vascular coating and tyramine-derived hydroxycinnamic acid amides restrict Ralstonia solanacearum colonization in resistant tomato. THE NEW PHYTOLOGIST 2022; 234:1411-1429. [PMID: 35152435 DOI: 10.1111/nph.17982] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Tomato varieties resistant to the bacterial wilt pathogen Ralstonia solanacearum have the ability to restrict bacterial movement in the plant. Inducible vascular cell wall reinforcements seem to play a key role in confining R. solanacearum into the xylem vasculature of resistant tomato. However, the type of compounds involved in such vascular physico-chemical barriers remain understudied, while being a key component of resistance. Here we use a combination of histological and live-imaging techniques, together with spectroscopy and gene expression analysis to understand the nature of R. solanacearum-induced formation of vascular coatings in resistant tomato. We describe that resistant tomato specifically responds to infection by assembling a vascular structural barrier formed by a ligno-suberin coating and tyramine-derived hydroxycinnamic acid amides. Further, we show that overexpressing genes of the ligno-suberin pathway in a commercial susceptible variety of tomato restricts R. solanacearum movement inside the plant and slows disease progression, enhancing resistance to the pathogen. We propose that the induced barrier in resistant plants does not only restrict the movement of the pathogen, but may also prevent cell wall degradation by the pathogen and confer anti-microbial properties, effectively contributing to resistance.
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Affiliation(s)
- Anurag Kashyap
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, 08193, Bellaterra, Spain
| | | | - Weiqi Zhang
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, 08193, Bellaterra, Spain
| | - Montserrat Capellades
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, 08193, Bellaterra, Spain
- Consejo Superior de Investigaciones Científicas (CSIC), 08001, Barcelona, Spain
| | - Sumithra Srinivasan
- Institute of Material Science of Barcelona (ICMAB), CSIC, Campus UAB, 08193, Bellaterra, Spain
| | - Anna Laromaine
- Institute of Material Science of Barcelona (ICMAB), CSIC, Campus UAB, 08193, Bellaterra, Spain
| | - Olga Serra
- Laboratori del Suro, Biology Department, University of Girona, Campus Montilivi, 17003, Girona, Spain
| | - Mercè Figueras
- Laboratori del Suro, Biology Department, University of Girona, Campus Montilivi, 17003, Girona, Spain
| | - Jorge Rencoret
- Institute of Natural Resources and Agrobiology of Seville (IRNAS), CSIC, 41012, Seville, Spain
| | - Ana Gutiérrez
- Institute of Natural Resources and Agrobiology of Seville (IRNAS), CSIC, 41012, Seville, Spain
| | - Marc Valls
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, 08193, Bellaterra, Spain
- Department of Genetics, University of Barcelona, 08028, Barcelona, Spain
| | - Nuria S Coll
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, 08193, Bellaterra, Spain
- Consejo Superior de Investigaciones Científicas (CSIC), 08001, Barcelona, Spain
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Chen M, Zhang W, Han L, Ru X, Cao Y, Hikichi Y, Ohnishi K, Pan G, Zhang Y. A CysB regulator positively regulates cysteine synthesis, expression of type III secretion system genes, and pathogenicity in Ralstonia solanacearum. MOLECULAR PLANT PATHOLOGY 2022; 23:679-692. [PMID: 35122373 PMCID: PMC8995062 DOI: 10.1111/mpp.13189] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 05/27/2023]
Abstract
A syringe-like type III secretion system (T3SS) plays essential roles in the pathogenicity of Ralstonia solanacearum, which is a causal agent of bacterial wilt disease on many plant species worldwide. Here, we characterized functional roles of a CysB regulator (RSc2427) in R. solanacearum OE1-1 that was demonstrated to be responsible for cysteine synthesis, expression of the T3SS genes, and pathogenicity of R. solanacearum. The cysB mutants were cysteine auxotrophs that failed to grow in minimal medium but grew slightly in host plants. Supplementary cysteine substantially restored the impaired growth of cysB mutants both in minimal medium and inside host plants. Genes of cysU and cysI regulons have been annotated to function for R. solanacearum cysteine synthesis; CysB positively regulated expression of these genes. Moreover, CysB positively regulated expression of the T3SS genes both in vitro and in planta through the PrhG to HrpB pathway, whilst impaired expression of the T3SS genes in cysB mutants was independent of growth deficiency under nutrient-limited conditions. CysB was also demonstrated to be required for exopolysaccharide production and swimming motility, which contribute jointly to the host colonization and infection process of R. solanacearum. Thus, CysB was identified here as a novel regulator on the T3SS expression in R. solanacearum. These results provide novel insights into understanding of various biological functions of CysB regulators and complex regulatory networks on the T3SS in R. solanacearum.
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Affiliation(s)
- Min Chen
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Weiqi Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Liangliang Han
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
| | - Xuejuan Ru
- Chongqing Academy of Agricultural SciencesChongqingChina
| | - Yuzhu Cao
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine ScienceKochi UniversityNankokuJapan
| | - Guanghui Pan
- Chongqing Academy of Agricultural SciencesChongqingChina
| | - Yong Zhang
- College of Resources and EnvironmentSouthwest UniversityChongqingChina
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River BasinSouthwest UniversityChongqingChina
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9
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Shang XC, Cai X, Zhou Y, Han X, Zhang CS, Ilyas N, Li Y, Zheng Y. Pseudomonas Inoculation Stimulates Endophytic Azospira Population and Induces Systemic Resistance to Bacterial Wilt. FRONTIERS IN PLANT SCIENCE 2021; 12:738611. [PMID: 36406638 PMCID: PMC9673043 DOI: 10.3389/fpls.2021.738611] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/19/2021] [Indexed: 06/04/2023]
Abstract
Bacterial communities in the rhizosphere play an important role in sustaining plant growth and the health of diverse soils. Recent studies have demonstrated that microbial keystone taxa in the rhizosphere microbial community are extremely critical for the suppression of diseases. However, the mechanisms involved in disease suppression by keystone species remain unclear. The present study assessed the effects of three Pseudomonas strains, which were identified as keystone species in our previous study, on the growth performance and root-associated bacterial community of tobacco plants. A high relative abundance of Ralstonia was found in the non-inoculated group, while a large Azospira population was observed in all groups inoculated with the three Pseudomonas strains. Correspondingly, the activities of the defense-related enzymes and the expression levels of the defense signaling marker genes of the plant were increased after inoculation with the Pseudomonas strains. Moreover, the correlation analyses showed that the relative abundance of Azospira, the activity of superoxide dismutase, catalase, and polyphenol oxidase, and the expression of H1N1, ACC Oxidase, and PR1 a/c had a significantly negative (p<0.05) relationship with the abundance of Ralstonia. This further revealed that the keystone species, such as Pseudomonas spp., can suppress bacterial wilt disease by enhancing the systemic resistance of tobacco plants.
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Affiliation(s)
- Xian-chao Shang
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xianjie Cai
- Shanghai Tobacco Group Co., Ltd., Shanghai, China
| | - Yanan Zhou
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Xiaobin Han
- Biological Organic Fertilizer Engineering Technology Center of China Tobacco, Zunyi Branch of Guizhou Tobacco Company, Zunyi, China
| | - Cheng-Sheng Zhang
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Naila Ilyas
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yiqiang Li
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Yanfen Zheng
- Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
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10
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Gopalan-Nair R, Jardinaud MF, Legrand L, Landry D, Barlet X, Lopez-Roques C, Vandecasteele C, Bouchez O, Genin S, Guidot A. Convergent Rewiring of the Virulence Regulatory Network Promotes Adaptation of Ralstonia solanacearum on Resistant Tomato. Mol Biol Evol 2021; 38:1792-1808. [PMID: 33306125 PMCID: PMC8097285 DOI: 10.1093/molbev/msaa320] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The evolutionary and adaptive potential of a pathogen is a key determinant for successful host colonization and proliferation but remains poorly known for most of the pathogens. Here, we used experimental evolution combined with phenotyping, genomics, and transcriptomics to estimate the adaptive potential of the bacterial plant pathogen Ralstonia solanacearum to overcome the quantitative resistance of the tomato cultivar Hawaii 7996. After serial passaging over 300 generations, we observed pathogen adaptation to within-plant environment of the resistant cultivar but no plant resistance breakdown. Genomic sequence analysis of the adapted clones revealed few genetic alterations, but we provide evidence that all but one were gain of function mutations. Transcriptomic analyses revealed that even if different adaptive events occurred in independently evolved clones, there is convergence toward a global rewiring of the virulence regulatory network as evidenced by largely overlapping gene expression profiles. A subset of four transcription regulators, including HrpB, the activator of the type 3 secretion system regulon and EfpR, a global regulator of virulence and metabolic functions, emerged as key nodes of this regulatory network that are frequently targeted to redirect the pathogen’s physiology and improve its fitness in adverse conditions. Significant transcriptomic variations were also detected in evolved clones showing no genomic polymorphism, suggesting that epigenetic modifications regulate expression of some of the virulence network components and play a major role in adaptation as well.
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Affiliation(s)
| | | | - Ludovic Legrand
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - David Landry
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Xavier Barlet
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | | | | | - Olivier Bouchez
- GeT-PlaGe, Genotoul, INRAE, US 1426, Castanet-Tolosan, France
| | - Stéphane Genin
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Alice Guidot
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
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11
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Zhang Y, Cao Y, Zhang L, Hikichi Y, Ohnishi K, Li J. The Tn 7-Based Genomic Integration Is Dependent on an attTn 7 Box in the glms Gene and Is Site-Specific With Monocopy in Ralstonia solanacearum Species Complex. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:720-725. [PMID: 33656355 DOI: 10.1094/mpmi-11-20-0325-sc] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The Tn7-based genomic integration system enables direct insertion of foreign gene elements into the chromosome downstream of glms in many bacteria species. The glms gene is greatly conserved in Ralstonia solanacearum species complex (RSSC), while its downstream regions are mostly different in the RSSC. Here, we provided genetic evidence to validate that this Tn7 integration is dependent on a conserved 30-bp motif in the glms, called an attTn7 box, and artificial attTn7 boxes elsewhere are competent for the Tn7 integration, which is further confirmed to be simultaneous downstream of both original and artificial attTn7 boxes, using PCR. With the whole-genome resequencing on 500 Tn7-colonies, the Tn7 integration was confirmed to be site- specific at 25 bp downstream of glms with monocopy as a chromosome of the RSSC. Characteristic of a monocopy in a chromosome enables the Tn7-based complementation to fully restore phenotypes of mutants to those of parent strains that are advantageous rather than those based on plasmids with low-copy numbers. The Tn7-based genomic integration system provides a generally applicable and versatile genetic tool for studies of complementation, pathogenesis, overexpression, and in-vivo promoter activity assays with monocopy in the RSSC.[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.
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Affiliation(s)
- Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Yuzhu Cao
- College of Resources and Environment, Southwest University, Chongqing, China
- Faculty of Agriculture and Marine Science, Kochi University, Japan
| | - Lichun Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
- Faculty of Agriculture and Marine Science, Kochi University, Japan
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine Science, Kochi University, Japan
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi University, Japan
| | - Jing Li
- The Ninth Peoples Hospital of Chongqing, Chongqing, China
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Lei N, Chen L, Kiba A, Hikichi Y, Zhang Y, Ohnishi K. Super-Multiple Deletion Analysis of Type III Effectors in Ralstonia solanacearum OE1-1 for Full Virulence Toward Host Plants. Front Microbiol 2020; 11:1683. [PMID: 32849353 PMCID: PMC7409329 DOI: 10.3389/fmicb.2020.01683] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/29/2020] [Indexed: 11/16/2022] Open
Abstract
Ralstonia solanacearum species complex (RSSC) posses extremely abundant type III effectors (T3Es) that are translocated into plant cells via a syringe-like apparatus assembled by a type III secretion system (T3SS) to subvert host defense initiated by innate immunity. More than 100 T3Es are predicted among different RSSC strains, with an average of about 70 T3Es in each strain. Among them, 32 T3Es are found to be conserved among the RSSC and hence called the core T3Es. Here, we genetically characterized contribution of abundant T3Es to virulence of a Japanese RSSC strain OE1-1 toward host plants. While all the T3Es members of AWR family contributed slightly to virulence, those of the GALA, HLK, and SKWP families did not influence full virulence of OE1-1. Mutant OE1-1D21E (with deletion of all 21 T3Es members of four families) exhibited slightly impaired virulence, while mutant OE1-1D36E (deleting all 21 T3Es of 4 families and 15 core T3Es) exhibited substantially reduced virulence. Mutant OE1-1D42E (deleting all 21 T3Es of 4 families, 15 core T3Es and 6 extended core T3Es) failed to cause any disease on tobacco plants with leaf infiltration but retained faint virulence on tobacco plants with petiole inoculation. The proliferation of mutant OE1-1D42E in tobacco stems was substantially impaired with about three orders of magnitude less than that of OE1-1, while no impact in tobacco leaves if directly infiltrated into leaves. On the contrary, the OE1-1D42E mutant retained faint virulence on eggplants with leaf infiltration but completely lost virulence on eggplants with root-cutting inoculation. The proliferation of OE1-1D42E mutant both in eggplant leaves and stems was substantially impaired. Intriguingly, mutant OE1-1D42E still caused necrotic lesions in tobacco and eggplant leaves, indicating that some other than the 42 removed effectors are involved in expansion of necrotic lesions in host leaves. All taken together, we here genetically demonstrated that all the core and extended core T3Es are nearly crucial for virulence of OE1-1 toward host plants and provided currently a kind of T3Es-free strain that enables primary functional studies of individual T3Es in host cells.
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Affiliation(s)
- Ni Lei
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Japan
| | - Li Chen
- College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi'an, China
| | - Akinori Kiba
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China.,Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, Southwest University, Chongqing, China
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi University, Kochi, Japan
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Li J, Han L, Chen N, Zhu C, Gao Y, Shi X, Xu C, Hikichi Y, Zhang Y, Ohnishi K. Functional Characterization of RsRsgA for Ribosome Biosynthesis and Expression of the Type III Secretion System in Ralstonia solanacearum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:972-981. [PMID: 32240066 DOI: 10.1094/mpmi-10-19-0294-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
RsgA plays an important role in maturation of 30S subunit in many bacteria that assists in the release of RbfA from the 30S subunit during a late stage of ribosome biosynthesis. Here, we genetically characterized functional roles of RsgA in Ralstonia solanacearum, hereafter designated RsRsgA. Deletion of R. solanacearum rsgA or rbfA resulted in distinct deficiency of 16S ribosomal RNA, significantly slowed growth in broth medium, and diminished growth in nutrient-limited medium, which are similar as phenotypes of rsgA mutants and rbfA mutants of Escherichia coli and other bacteria. Our gene-expression studies revealed that RsRsgA is important for expression of genes encoding the type III secretion system (T3SS) (a pathogenicity determinant of R. solanacearum) both in vitro and in planta. Compared with the wild-type R. solanacearum strain, proliferation of the rsgA and rbfA mutants in tobacco leaves was significantly impaired, while they failed to migrate into tobacco xylem vessels from infiltrated leaves, and hence, these two mutants failed to cause any bacterial wilt disease in tobacco plants. It was further revealed that rsgA expression was highly enhanced under nutrient-limited conditions compared with that in broth medium and RsRsgA affects T3SS expression through the PrhN-PrhG-HrpB pathway. Moreover, expression of a subset of type III effectors was substantially impaired in the rsgA mutant, some of which are responsible for R. solanacearum GMI1000 elicitation of a hypersensitive response (HR) in tobacco leaves, while RsRsgA is not required for HR elicitation of GMI1000 in tobacco leaves. All these results provide novel insights into understanding various biological functions of RsgA proteins and complex regulation on the T3SS in R. solanacearum.
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Affiliation(s)
- Jiaman Li
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Liangliang Han
- College of Resources and Environment, Southwest University, Chongqing, China
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Nan Chen
- College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing, China
| | - Chao Zhu
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Yuwei Gao
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Xiaojun Shi
- College of Resources and Environment, Southwest University, Chongqing, China
- Key Laboratory of Efficient Utilization of Soil and Fertilizer Resources, Chongqing, China
| | - Changzheng Xu
- College of Life Science, Southwest University, Chongqing, China
| | - Yasufumi Hikichi
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
| | - Yong Zhang
- College of Resources and Environment, Southwest University, Chongqing, China
- Key Laboratory of Efficient Utilization of Soil and Fertilizer Resources, Chongqing, China
| | - Kouhei Ohnishi
- Faculty of Agriculture and Marine Science, Kochi University, Kochi, Japan
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Doin de Moura GG, Remigi P, Masson-Boivin C, Capela D. Experimental Evolution of Legume Symbionts: What Have We Learnt? Genes (Basel) 2020; 11:E339. [PMID: 32210028 PMCID: PMC7141107 DOI: 10.3390/genes11030339] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
Rhizobia, the nitrogen-fixing symbionts of legumes, are polyphyletic bacteria distributed in many alpha- and beta-proteobacterial genera. They likely emerged and diversified through independent horizontal transfers of key symbiotic genes. To replay the evolution of a new rhizobium genus under laboratory conditions, the symbiotic plasmid of Cupriavidus taiwanensis was introduced in the plant pathogen Ralstonia solanacearum, and the generated proto-rhizobium was submitted to repeated inoculations to the C. taiwanensis host, Mimosa pudica L.. This experiment validated a two-step evolutionary scenario of key symbiotic gene acquisition followed by genome remodeling under plant selection. Nodulation and nodule cell infection were obtained and optimized mainly via the rewiring of regulatory circuits of the recipient bacterium. Symbiotic adaptation was shown to be accelerated by the activity of a mutagenesis cassette conserved in most rhizobia. Investigating mutated genes led us to identify new components of R. solanacearum virulence and C. taiwanensis symbiosis. Nitrogen fixation was not acquired in our short experiment. However, we showed that post-infection sanctions allowed the increase in frequency of nitrogen-fixing variants among a non-fixing population in the M. pudica-C. taiwanensis system and likely allowed the spread of this trait in natura. Experimental evolution thus provided new insights into rhizobium biology and evolution.
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Affiliation(s)
| | | | | | - Delphine Capela
- LIPM, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan 31320, France; (G.G.D.d.M.); (P.R.); (C.M.-B.)
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