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Hwang IS, Oh EJ, Oh CS. A novel virulence gene, cviA1 of Clavibacter michiganensis for necrosis development in the Nicotiana benthamiana plant. Microbiol Res 2024; 285:127743. [PMID: 38733725 DOI: 10.1016/j.micres.2024.127743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/06/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024]
Abstract
Clavibacter michiganensis is a Gram-positive bacterium that causes diverse disease symptoms in tomatoes and Nicotiana benthamiana, a surrogate host plant, including canker, blister lesions, and wilting. Previously, we reported that C. michiganensis also causes necrosis in N. benthamiana leaves. Here, to identify novel virulence genes of C. michiganensis required for necrosis development in N. benthamiana leaves, we screened 1,862 transposon-inserted mutants and identified a mutant strain that exhibited weak and delayed necrosis, whereas there was no discernible difference in blister lesions, canker, or wilting symptoms. Notably, this mutant caused canker similar to that of the wild-type strain, but caused mild wilting in tomato. This mutant carried a transposon in a chromosomal gene, called Clavibactervirulence gene A1 (cviA1). CviA1 encodes a 180-amino acid protein with a signal peptide (SP) at the N-terminus and two putative transmembrane domains (TMs) at the C-terminus. Interestingly, deletion of the SP or the C-terminus, including the two putative TMs, in CviA1 failed to restore full necrosis in the mutant, highlighting the importance of protein secretion and the putative TMs for necrosis. A paralog of cviA1, cviA2 is located on the large plasmid pCM2 of C. michiganensis. Despite its high similarity to cviA1, the introduction of cviA2 into the cviA1 mutant strain did not restore virulence. Similarly, the introduction of cviA1 into the Clavibacter capsici type strain PF008, which initially lacks cviA1, did not enhance necrosis symptoms. These results reveals that the chromosomal cviA1 gene in C. michiganensis plays an important role in necrosis development in N. benthamiana leaves.
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Affiliation(s)
- In Sun Hwang
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, the Republic of Korea
| | - Eom-Ji Oh
- Plant Immunity Research Center, Seoul National University, Seoul 08826, the Republic of Korea
| | - Chang-Sik Oh
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, the Republic of Korea; Plant Immunity Research Center, Seoul National University, Seoul 08826, the Republic of Korea; Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, the Republic of Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, the Republic of Korea.
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2
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Koseoglou E, Hanika K, Mohd Nadzir MM, Kohlen W, van der Wolf JM, Visser RGF, Bai Y. Inactivation of tomato WAT1 leads to reduced susceptibility to Clavibacter michiganensis through downregulation of bacterial virulence factors. FRONTIERS IN PLANT SCIENCE 2023; 14:1082094. [PMID: 37324660 PMCID: PMC10264788 DOI: 10.3389/fpls.2023.1082094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 05/05/2023] [Indexed: 06/17/2023]
Abstract
Tomato bacterial canker caused by Clavibacter michiganensis (Cm) is considered to be one of the most destructive bacterial diseases of tomato. To date, no resistance to the pathogen has been identified. While several molecular studies have identified (Cm) bacterial factors involved in disease development, the plant genes and mechanisms associated with susceptibility of tomato to the bacterium remain largely unknown. Here, we show for the first time that tomato gene SlWAT1 is a susceptibility gene to Cm. We inactivated the gene SlWAT1 through RNAi and CRISPR/Cas9 to study changes in tomato susceptibility to Cm. Furthermore, we analysed the role of the gene in the molecular interaction with the pathogen. Our findings demonstrate that SlWAT1 functions as an S gene to genetically diverse Cm strains. Inactivation of SlWAT1 reduced free auxin contents and ethylene synthesis in tomato stems and suppressed the expression of specific bacterial virulence factors. However, CRISPR/Cas9 slwat1 mutants exhibited severe growth defects. The observed reduced susceptibility is possibly a result of downregulation of bacterial virulence factors and reduced auxin contents in transgenic plants. This shows that inactivation of an S gene may affect the expression of bacterial virulence factors.
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Affiliation(s)
- Eleni Koseoglou
- Plant Breeding, Wageningen University & Research, Wageningen, Netherlands
- Graduate School Experimental Plant Sciences Wageningen University & Research, Wageningen, Netherlands
| | - Katharina Hanika
- Plant Breeding, Wageningen University & Research, Wageningen, Netherlands
| | - Mas M. Mohd Nadzir
- Plant Breeding, Wageningen University & Research, Wageningen, Netherlands
| | - Wouter Kohlen
- Cluster of Plant Developmental Biology, Laboratory of Molecular Biology, Wageningen University & Research, Wageningen, Netherlands
| | - Jan M. van der Wolf
- Biointeractions & Plant Health, Wageningen University & Research, Wageningen, Netherlands
| | | | - Yuling Bai
- Plant Breeding, Wageningen University & Research, Wageningen, Netherlands
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3
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Verma RK, Teper D. Immune recognition of the secreted serine protease ChpG restricts the host range of Clavibacter michiganensis from eggplant varieties. MOLECULAR PLANT PATHOLOGY 2022; 23:933-946. [PMID: 35441490 PMCID: PMC9190982 DOI: 10.1111/mpp.13215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 05/06/2023]
Abstract
Bacterial wilt and canker caused by Clavibacter michiganensis (Cm) inflict considerable damage in tomato-growing regions around the world. Cm has a narrow host range and can cause disease in tomato but not in many eggplant varieties. The pathogenicity of Cm is dependent on secreted serine proteases, encoded by the chp/tomA pathogenicity island (PI), and the pCM2 plasmid. Screening combinations of PI deletion mutants and plasmid-cured strains found that Cm-mediated hypersensitive response (HR) in the Cm-resistant eggplant variety Black Queen is dependent on the chp/tomA PI. Singular reintroduction of PI-encoded serine proteases into Cm∆PI identified that the HR is elicited by the protease ChpG. Eggplant leaves infiltrated with a chpG marker exchange mutant (CmΩchpG) did not display an HR, and infiltration of purified ChpG protein elicited immune responses in eggplant but not in Cm-susceptible tomato. Virulence assays found that while wild-type Cm and the CmΩchpG complemented strain were nonpathogenic on eggplant, CmΩchpG caused wilt and canker symptoms. Additionally, bacterial populations in CmΩchpG-inoculated eggplant stem tissues were c.1000-fold higher than wild-type and CmΩchpG-complemented Cm strains. Pathogenicity tests conducted in multiple Cm-resistance eggplant varieties demonstrated that immunity to Cm is dependent on ChpG in all tested varieties, indicating that ChpG-recognition is conserved in eggplant. ChpG-mediated avirulence interactions were disabled by alanine substitution of serine231 of the serine protease catalytic triad, suggesting that protease activity is required for immune recognition of ChpG. Our study identified ChpG as a novel avirulence protein that is recognized in resistant eggplant varieties and restricts the host range of Cm.
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Affiliation(s)
- Raj Kumar Verma
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationVolcani InstituteRishon LeZionIsrael
| | - Doron Teper
- Department of Plant Pathology and Weed ResearchAgricultural Research OrganizationVolcani InstituteRishon LeZionIsrael
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4
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Chen X, Bai K, Lyu Q, Jiang N, Li J, Luo L. Role of Penicillin-Binding Proteins in the Viability, Morphology, Stress Tolerance, and Pathogenicity of Clavibacter michiganensis. PHYTOPATHOLOGY 2021; 111:1301-1312. [PMID: 33369478 DOI: 10.1094/phyto-08-20-0326-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Previous research has shown that penicillin-binding proteins (PBPs), enzymes involved in peptidoglycan (PG) assembly, could play an important role during the induction of the viable but nonculturable (VBNC) state, which allows non-spore-forming bacteria to survive adverse environmental conditions. The current study found that Clavibacter michiganensis has seven PBPs. Mutant analysis indicated that deletion of either of the class B PBPs was lethal and that the class A PBPs had an important role in PG synthesis, with the ΔpbpC mutant having an altered cellular morphology that resulted in longer cells that were swollen at one end and had thinner cell walls. The ΔpbpC mutant was also found to produce mucoid colonies in solid culture and a lower final cell titer in liquid medium, as well as having high sensitivity to osmotic stress and lysozyme treatment and surprisingly high pathogenicity. The double mutant, ΔdacB/ΔpbpE, also had a slightly altered phenotype, resulting in longer cells. Further analysis revealed that both mutants had high sensitivity to copper, which resulted in quicker induction into the VBNC state. However, only the ΔpbpC mutant had significantly reduced survivorship in the VBNC state. The study also confirmed that the VBNC state significantly improved the survivorship of wild-type C. michiganensis cells in response to environmental stresses and systemically demonstrated the protective role of the VBNC state in C. michiganensis, which is an important finding regarding its epidemiology and has serious implications for disease management.
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Affiliation(s)
- Xing Chen
- Department of Plant Pathology, College of Plant Protection, China Agricultural University; Beijing Key Laboratory of Seed Disease Testing and Control, Beijing 100193, P.R. China
| | - Kaihong Bai
- Department of Plant Pathology, College of Plant Protection, China Agricultural University; Beijing Key Laboratory of Seed Disease Testing and Control, Beijing 100193, P.R. China
| | - Qingyang Lyu
- Department of Plant Pathology, College of Plant Protection, China Agricultural University; Beijing Key Laboratory of Seed Disease Testing and Control, Beijing 100193, P.R. China
- Key Laboratory of Environmental and Applied Microbiology, CAS, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P.R. China
| | - Na Jiang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University; Beijing Key Laboratory of Seed Disease Testing and Control, Beijing 100193, P.R. China
| | - Jianqiang Li
- Department of Plant Pathology, College of Plant Protection, China Agricultural University; Beijing Key Laboratory of Seed Disease Testing and Control, Beijing 100193, P.R. China
| | - Laixin Luo
- Department of Plant Pathology, College of Plant Protection, China Agricultural University; Beijing Key Laboratory of Seed Disease Testing and Control, Beijing 100193, P.R. China
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Peritore-Galve FC, Tancos MA, Smart CD. Bacterial Canker of Tomato: Revisiting a Global and Economically Damaging Seedborne Pathogen. PLANT DISEASE 2021; 105:1581-1595. [PMID: 33107795 DOI: 10.1094/pdis-08-20-1732-fe] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The gram-positive actinobacterium Clavibacter michiganensis is the causal agent of bacterial canker of tomato, an economically impactful disease with a worldwide distribution. This seedborne pathogen systemically colonizes tomato xylem leading to unilateral leaflet wilt, marginal leaf necrosis, stem and petiole cankers, and plant death. Additionally, splash dispersal of the bacterium onto fruit exteriors causes bird's-eye lesions, which are characterized as necrotic centers surrounded by white halos. The pathogen can colonize developing seeds systemically through xylem and through penetration of fruit tissues from the exterior. There are currently no commercially available resistant cultivars, and bactericidal sprays have limited efficacy for managing the disease once the pathogen is in the vascular system. In this review, we summarize research on epidemiology, host colonization, the bacterial genetics underlying virulence, and management of bacterial canker. Finally, we highlight important areas of research into this pathosystem that have the potential to generate new strategies for prevention and mitigation of bacterial canker.
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Affiliation(s)
- F Christopher Peritore-Galve
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456
| | - Matthew A Tancos
- Foreign Disease-Weed Science Research Unit, United States Department of Agriculture-Agricultural Research Service, Frederick, MD 21702
| | - Christine D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456
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Nardella C, Barile A, di Salvo ML, Milano T, Pascarella S, Tramonti A, Contestabile R. Interaction of Bacillus subtilis GabR with the gabTD promoter: role of repeated sequences and effect of GABA in transcriptional activation. FEBS J 2020; 287:4952-4970. [PMID: 32147931 DOI: 10.1111/febs.15286] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/20/2020] [Accepted: 03/06/2020] [Indexed: 12/15/2022]
Abstract
Bacillus subtilis is able to use γ-aminobutyric acid (GABA) found in the soil as carbon and nitrogen source, through the action of GABA aminotransferase (GabT) and succinic semialdehyde dehydrogenase (GabD). GABA acts as molecular effector in the transcriptional activation of the gabTD operon by GabR. GabR is the most studied member of the MocR family of prokaryotic pyridoxal 5'-phosphate (PLP)-dependent transcriptional regulators, yet crucial aspects of its mechanism of action are unknown. GabR binds to the gabTD promoter, but transcription is activated only when GABA is present. Here, we demonstrated, in contrast with what had been previously proposed, that three repeated nucleotide sequences in the promoter region, two direct repeats and one inverted repeat, are specifically recognized by GabR. We carried out in vitro and in vivo experiments using mutant forms of the gabTD promoter. Our results showed that GABA activates transcription by changing the modality of interaction between GabR and the recognized sequence repeats. A hypothetical model is proposed in which GabR exists in two alternative conformations that, respectively, prevent or promote transcription. According to this model, in the absence of GABA, GabR binds to DNA interacting with all three sequence repeats, overlapping the RNA polymerase binding site and therefore preventing transcription activation. On the other hand, when GABA binds to GabR, a conformational change of the protein leads to the release of the interaction with the inverted repeat, allowing transcription initiation by RNA polymerase.
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Affiliation(s)
- Caterina Nardella
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, Italy
| | - Anna Barile
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, Italy.,Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Roma, Italy
| | - Martino L di Salvo
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, Italy
| | - Teresa Milano
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, Italy
| | - Stefano Pascarella
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, Italy
| | - Angela Tramonti
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, Italy.,Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Roma, Italy
| | - Roberto Contestabile
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, Italy
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7
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Comparative Genomics and Phylogenetic Analyses Suggest Several Novel Species within the Genus Clavibacter, Including Nonpathogenic Tomato-Associated Strains. Appl Environ Microbiol 2020; 86:AEM.02873-19. [PMID: 31924620 DOI: 10.1128/aem.02873-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 01/07/2020] [Indexed: 02/06/2023] Open
Abstract
Members of the genus Clavibacter are economically important bacterial plant pathogens infecting a set of diverse agricultural crops (e.g., alfalfa, corn, potato, tomato, and wheat). Tomato-associated Clavibacter sp. strains account for a great portion of the genetic diversity of the genus, and C. michiganensis sensu stricto (formerly C. michiganensis subsp. michiganensis), causing bacterial canker disease, is considered one of the most destructive seed-borne agents for the crop worldwide. However, current taxonomic descriptions of the genus do not reflect the existing diversity of the strains, resulting in unsatisfactory results in quarantine surveys for the pathogens. In this study, we used all the available genome sequences of Clavibacter sp. strains, including the type strains of newly described subspecies, to provide precise insight into the diversity of tomato-associated members of the genus and further clarify the taxonomic status of the strains using genotypic and phenotypic features. The results of phylogenetic analyses revealed the existence of nine hypothetical new species among the investigated strains. None of the three new subspecies (i.e., C. michiganensis subsp. californiensis, C. michiganensis subsp. chilensis, and C. michiganensis subsp. phaseoli) is included within the tomato-pathogenic C. michiganensis sensu stricto lineage. Although comparative genomics revealed the lack of chp and tomA pathogenicity determinant gene clusters in the nonpathogenic strains, a number of pathogenicity-related genes were noted to be present in all the strains regardless of their pathogenicity characteristics. Altogether, our results indicate a need for a formal taxonomic reconsideration of tomato-associated Clavibacter sp. strains to facilitate differentiation of the lineages in quarantine inspections.IMPORTANCE Clavibacter spp. are economically important bacterial plant pathogens infecting a set of diverse agricultural crops, such as alfalfa, corn, pepper, potato, tomato, and wheat. A number of plant-pathogenic members of the genus (e.g., C. michiganensis sensu stricto and C. sepedonicus, infecting tomato and potato plants, respectively) are included in the A2 (high-risk) list of quarantine pathogens by the European and Mediterranean Plant Protection Organization (EPPO). Although tomato-associated members of Clavibacter spp. account for a significant portion of the genetic diversity in the genus, only the strains belonging to C. michiganensis sensu stricto (formerly C. michiganensis subsp. michiganensis) cause bacterial canker disease of tomato and are subjected to the quarantine inspections. Hence, discrimination between the pathogenic and nonpathogenic Clavibacter sp. strains associated with tomato seeds and transplants plays a pivotal role in the accurate detection and cost-efficient management of the disease. On the other hand, detailed information on the genetic contents of different lineages of the genus would lead to the development of genome-informed specific detection techniques. In this study, we have provided an overview of the phylogenetic and genomic differences between the pathogenic and nonpathogenic tomato-associated Clavibacter sp. strains. We also noted that the taxonomic status of newly introduced subspecies of C. michiganensis (i.e., C. michiganensis subsp. californiensis, C. michiganensis subsp. chilensis, and C. michiganensis subsp. phaseoli) should be reconsidered.
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8
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Tramonti A, Nardella C, di Salvo ML, Pascarella S, Contestabile R. The MocR-like transcription factors: pyridoxal 5'-phosphate-dependent regulators of bacterial metabolism. FEBS J 2018; 285:3925-3944. [PMID: 29974999 DOI: 10.1111/febs.14599] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/14/2018] [Accepted: 06/25/2018] [Indexed: 12/22/2022]
Abstract
Many biological functions played by current proteins were not created by evolution from scratch, rather they were obtained combining already available protein scaffolds. This is the case of MocR-like bacterial transcription factors (MocR-TFs), a subclass of GntR transcription regulators, whose structure is the outcome of the fusion between DNA-binding proteins and pyridoxal 5'-phosphate (PLP)-dependent enzymes. The resultant chimeras can count on the properties of both protein classes, i.e. the capability to recognize specific DNA sequences and to bind PLP and amino-compounds; it is the modulation of such binding properties to confer to MocR-TFs chimeras the ability to interact with effector molecules and DNA so as to regulate transcription. MocR-TFs control different metabolic processes involving vitamin B6 and amino acids, which are canonical ligands of PLP-dependent enzymes. However, MocR-TFs are also implicated in the metabolism of compounds that are not substrates of PLP-dependent enzymes, such as rhizopine and ectoine. Genomic analyses show that MocR-TFs are widespread among eubacteria, implying an essential role in their metabolism and highlighting the scarcity of our knowledge on these important players in microbial metabolism. Although MocR-TFs have been discovered 15 years ago, the research activity on these transcriptional regulators has only recently intensified, producing a wealth of information that needs to be brought back to general principles. This is the main task of this review, which reports and analyses the available information concerning MocR-TFs functional role, structural features, interaction with effector molecules and the characteristics of DNA transcriptional factor-binding sites of MocR-based regulatory systems.
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Affiliation(s)
- Angela Tramonti
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Roma, Italy.,Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza Università di Roma, Italy
| | - Caterina Nardella
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza Università di Roma, Italy
| | - Martino L di Salvo
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza Università di Roma, Italy
| | - Stefano Pascarella
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza Università di Roma, Italy
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza Università di Roma, Italy
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Nandi M, Macdonald J, Liu P, Weselowski B, Yuan Z. Clavibacter michiganensis ssp. michiganensis: bacterial canker of tomato, molecular interactions and disease management. MOLECULAR PLANT PATHOLOGY 2018; 19:2036-2050. [PMID: 29528201 PMCID: PMC6638088 DOI: 10.1111/mpp.12678] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 03/06/2018] [Accepted: 03/07/2018] [Indexed: 05/11/2023]
Abstract
Bacterial canker disease is considered to be one of the most destructive diseases of tomato (Solanum lycopersicum), and is caused by the seed-borne Gram-positive bacterium Clavibacter michiganensis ssp. michiganensis (Cmm). This vascular pathogen generally invades and proliferates in the xylem through natural openings or wounds, causing wilt and canker symptoms. The incidence of symptomless latent infections and the invasion of tomato seeds by Cmm are widespread. Pathogenicity is mediated by virulence factors and transcriptional regulators encoded by the chromosome and two natural plasmids. The virulence factors include serine proteases, cell wall-degrading enzymes (cellulases, xylanases, pectinases) and others. Mutational analyses of these genes and gene expression profiling (via quantitative reverse transcription-polymerase chain reaction, transcriptomics and proteomics) have begun to shed light on their roles in colonization and virulence, whereas the expression of tomato genes in response to Cmm infection suggests plant factors involved in the defence response. These findings may aid in the generation of target-specific bactericides or new resistant varieties of tomato. Meanwhile, various chemical and biological controls have been researched to control Cmm. This review presents a detailed investigation regarding the pathogen Cmm, bacterial canker infection, molecular interactions between Cmm and tomato, and current perspectives on improved disease management.
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Affiliation(s)
- Munmun Nandi
- Department of Microbiology & Immunology, Schulich School of Medicine & DentistryUniversity of Western OntarioLondonONCanada, N6A 5C1
| | - Jacqueline Macdonald
- Department of Microbiology & Immunology, Schulich School of Medicine & DentistryUniversity of Western OntarioLondonONCanada, N6A 5C1
| | - Peng Liu
- Department of Microbiology & Immunology, Schulich School of Medicine & DentistryUniversity of Western OntarioLondonONCanada, N6A 5C1
| | - Brian Weselowski
- London Research and Development Centre, Agriculture & Agri‐Food CanadaLondonONCanada, N5V 4T3
| | - Ze‐Chun Yuan
- Department of Microbiology & Immunology, Schulich School of Medicine & DentistryUniversity of Western OntarioLondonONCanada, N6A 5C1
- London Research and Development Centre, Agriculture & Agri‐Food CanadaLondonONCanada, N5V 4T3
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Lu Y, Ishimaru CA, Glazebrook J, Samac DA. Comparative Genomic Analyses of Clavibacter michiganensis subsp. insidiosus and Pathogenicity on Medicago truncatula. PHYTOPATHOLOGY 2018; 108:172-185. [PMID: 28952422 DOI: 10.1094/phyto-05-17-0171-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Clavibacter michiganensis is the most economically important gram-positive bacterial plant pathogen, with subspecies that cause serious diseases of maize, wheat, tomato, potato, and alfalfa. Much less is known about pathogenesis involving gram-positive plant pathogens than is known for gram-negative bacteria. Comparative genome analyses of C. michiganensis subspecies affecting tomato, potato, and maize have provided insights on pathogenicity. In this study, we identified strains of C. michiganensis subsp. insidiosus with contrasting pathogenicity on three accessions of the model legume Medicago truncatula. We generated complete genome sequences for two strains and compared these to a previously sequenced strain and genome sequences of four other subspecies. The three C. michiganensis subsp. insidiosus strains varied in gene content due to genome rearrangements, most likely facilitated by insertion elements, and plasmid number, which varied from one to three depending on strain. The core C. michiganensis genome consisted of 1,917 genes, with 379 genes unique to C. michiganensis subsp. insidiosus. An operon for synthesis of the extracellular blue pigment indigoidine, enzymes for pectin degradation, and an operon for inositol metabolism are among the unique features. Secreted serine proteases belonging to both the pat-1 and ppa families were present but highly diverged from those in other subspecies.
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Affiliation(s)
- You Lu
- First and third authors: Department of Plant and Microbial Biology, second and fourth authors: Department of Plant Pathology, and first, second, third, and fourth authors: the Microbial and Plant Genomics Institute, University of Minnesota, St. Paul 55108; and fourth author: United States Department of Agriculture-Agricultural Research Service, Plant Science Research, St. Paul, MN 55108
| | - Carol A Ishimaru
- First and third authors: Department of Plant and Microbial Biology, second and fourth authors: Department of Plant Pathology, and first, second, third, and fourth authors: the Microbial and Plant Genomics Institute, University of Minnesota, St. Paul 55108; and fourth author: United States Department of Agriculture-Agricultural Research Service, Plant Science Research, St. Paul, MN 55108
| | - Jane Glazebrook
- First and third authors: Department of Plant and Microbial Biology, second and fourth authors: Department of Plant Pathology, and first, second, third, and fourth authors: the Microbial and Plant Genomics Institute, University of Minnesota, St. Paul 55108; and fourth author: United States Department of Agriculture-Agricultural Research Service, Plant Science Research, St. Paul, MN 55108
| | - Deborah A Samac
- First and third authors: Department of Plant and Microbial Biology, second and fourth authors: Department of Plant Pathology, and first, second, third, and fourth authors: the Microbial and Plant Genomics Institute, University of Minnesota, St. Paul 55108; and fourth author: United States Department of Agriculture-Agricultural Research Service, Plant Science Research, St. Paul, MN 55108
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11
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Thapa SP, Pattathil S, Hahn MG, Jacques MA, Gilbertson RL, Coaker G. Genomic Analysis of Clavibacter michiganensis Reveals Insight Into Virulence Strategies and Genetic Diversity of a Gram-Positive Bacterial Pathogen. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:786-802. [PMID: 28677494 DOI: 10.1094/mpmi-06-17-0146-r] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Clavibacter michiganensis subsp. michiganensis is a gram-positive bacterial pathogen that proliferates in the xylem vessels of tomato, causing bacterial canker disease. In this study, we sequenced and assembled genomes of 11 C. michiganensis subsp. michiganensis strains isolated from infected tomato fields in California as well as five Clavibacter strains that colonize tomato endophytically but are not pathogenic in this host. The analysis of the C. michiganensis subsp. michiganensis genomes supported the monophyletic nature of this pathogen but revealed genetic diversity among strains, consistent with multiple introduction events. Two tomato endophytes that clustered phylogenetically with C. michiganensis strains capable of infecting wheat and pepper and were also able to cause disease in these plants. Plasmid profiles of the California strains were variable and supported the essential role of the pCM1-like plasmid and the CelA cellulase in virulence, whereas the absence of the pCM2-like plasmid in some pathogenic C. michiganensis subsp. michiganensis strains revealed it is not essential. A large number of secreted C. michiganensis subsp. michiganensis proteins were carbohydrate-active enzymes (CAZymes). Glycome profiling revealed that C. michiganensis subsp. michiganensis but not endophytic Clavibacter strains is able to extensively alter tomato cell-wall composition. Two secreted CAZymes found in all C. michiganensis subsp. michiganensis strains, CelA and PelA1, enhanced pathogenicity on tomato. Collectively, these results provide a deeper understanding of C. michiganensis subsp. michiganensis diversity and virulence strategies.
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Affiliation(s)
- Shree P Thapa
- 1 Department of Plant Pathology, University of California, Davis, California, U.S.A
| | - Sivakumar Pattathil
- 2 Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia, U.S.A.; and
| | - Michael G Hahn
- 2 Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia, U.S.A.; and
| | | | - Robert L Gilbertson
- 1 Department of Plant Pathology, University of California, Davis, California, U.S.A
| | - Gitta Coaker
- 1 Department of Plant Pathology, University of California, Davis, California, U.S.A
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Chalupowicz L, Barash I, Reuven M, Dror O, Sharabani G, Gartemann K, Eichenlaub R, Sessa G, Manulis‐Sasson S. Differential contribution of Clavibacter michiganensis ssp. michiganensis virulence factors to systemic and local infection in tomato. MOLECULAR PLANT PATHOLOGY 2017; 18:336-346. [PMID: 26992141 PMCID: PMC6638269 DOI: 10.1111/mpp.12400] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 03/13/2016] [Accepted: 03/15/2016] [Indexed: 05/03/2023]
Abstract
Clavibacter michiganensis ssp. michiganensis (Cmm) causes substantial economic losses in tomato production worldwide. The disease symptoms observed in plants infected systemically by Cmm are wilting and canker on the stem, whereas blister-like spots develop in locally infected leaves. A wide repertoire of serine proteases and cell wall-degrading enzymes has been implicated in the development of wilt and canker symptoms. However, virulence factors involved in the formation of blister-like spots, which play an important role in Cmm secondary spread in tomato nurseries, are largely unknown. Here, we demonstrate that Cmm virulence factors play different roles during blister formation relative to wilting. Inoculation with a green fluorescent protein (GFP)-labelled Cmm382 indicates that penetration occurs mainly through trichomes. When spray inoculated on tomato leaves, the wild-type Cmm382 and Cmm100 (lacking plasmids pCM1 and pCM2) strains form blister-like spots on leaves, whereas Cmm27 (lacking the chp/tomA pathogenicity island) is non-pathogenic, indicating that plasmid-borne genes, which have a crucial role in wilting, are not required for blister formation. Conversely, mutations in chromosomal genes encoding serine proteases (chpC and sbtA), cell wall-degrading enzymes (pgaA and endX/Y), a transcriptional regulator (vatr2), a putative perforin (perF) and a putative sortase (srtA) significantly affect disease incidence and the severity of blister formation. The transcript levels of these genes, as measured by quantitative reverse transcription-polymerase chain reaction, showed that, during blister formation, they are expressed early at 8-16 h after inoculation, whereas, during wilting, they are expressed after 24-72 h or expressed at low levels. Plant gene expression studies suggest that chpC is involved in the suppression of host defence.
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Affiliation(s)
- Laura Chalupowicz
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
| | - Isaac Barash
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel Aviv UniversityTel Aviv69978Israel
| | - Michal Reuven
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
| | - Orit Dror
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
| | - Galit Sharabani
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
| | - Karl‐Heinz Gartemann
- Department of Genetechnology/MicrobiologyUniversity of BielefeldBielefeld33501Germany
| | - Rudolf Eichenlaub
- Department of Genetechnology/MicrobiologyUniversity of BielefeldBielefeld33501Germany
| | - Guido Sessa
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel Aviv UniversityTel Aviv69978Israel
| | - Shulamit Manulis‐Sasson
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterBet Dagan50250Israel
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A Proteomic Study of Clavibacter Michiganensis Subsp. Michiganensis Culture Supernatants. Proteomes 2015; 3:411-423. [PMID: 28248277 PMCID: PMC5217389 DOI: 10.3390/proteomes3040411] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/30/2015] [Accepted: 11/10/2015] [Indexed: 11/23/2022] Open
Abstract
Clavibacter michiganensis, subsp. michiganensis is a Gram-positive plant pathogen infecting tomato (Solanum lycopersicum). Despite a considerable economic importance due to significant losses of infected plants and fruits, knowledge about virulence factors of C. michiganensis subsp. michiganensis and host-pathogen interactions on a molecular level are rather limited. In the study presented here, the proteome of culture supernatants from C. michiganensis subsp. michiganensis NCPPB382 was analyzed. In total, 1872 proteins were identified in M9 and 1766 proteins in xylem mimicking medium. Filtration of supernatants before protein precipitation reduced these to 1276 proteins in M9 and 976 proteins in the xylem mimicking medium culture filtrate. The results obtained indicate that C. michiganensis subsp. michiganensis reacts to a sucrose- and glucose-depleted medium similar to the xylem sap by utilizing amino acids and host cell polymers as well as their degradation products, mainly peptides, amino acids and various C5 and C6 sugars. Interestingly, the bacterium expresses the previously described virulence factors Pat-1 and CelA not exclusively after host cell contact in planta but already in M9 minimal and xylem mimicking medium.
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14
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Sen Y, van der Wolf J, Visser RGF, van Heusden S. Bacterial Canker of Tomato: Current Knowledge of Detection, Management, Resistance, and Interactions. PLANT DISEASE 2015; 99:4-13. [PMID: 30699746 DOI: 10.1094/pdis-05-14-0499-fe] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Clavibacter michiganensis subsp. michiganensis is the causal agent of bacterial canker of tomato. The disease was first described in 1910 in Michigan, USA. C. michiganensis subsp. michiganensis (from now on called clavibacter) was initially thought to be a phloem parasite, but was later found to be a xylem-invading bacterium. The host range comprises mainly solanaceous crops such as tomato, pepper, and eggplant. Strains show great variability in virulence and are usually described as being hypervirulent, hypovirulent, or nonvirulent. Clavibacter lacks a type III secretion system, and only a few virulence factors have been experimentally determined from the many putative virulence factors. As the molecular mode of infection by clavibacter is unknown, researchers have avoided intensive work on this organism. Genetic plant mechanisms conferring resistance to clavibacter are apparently complex, and breeders have yet to develop disease-resistant cultivars.
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Affiliation(s)
- Yusuf Sen
- Wageningen UR Plant Breeding, Wageningen University and Research Centre, Wageningen, The Netherlands, and Graduate School Experimental Plant Sciences, Wageningen, The Netherlands
| | - Jan van der Wolf
- Plant Research International Biointeractions and Plant Health, Wageningen, The Netherlands
| | - Richard G F Visser
- Wageningen UR Plant Breeding, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Sjaak van Heusden
- Wageningen UR Plant Breeding, Wageningen University and Research Centre, Wageningen, The Netherlands
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