1
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Lau MML, Kho CJY, Chung HH, Zulkharnain A. Isolation, identification and characterisation of Pseudomonas koreensis CM-01 isolated from diseased Malaysian mahseer (Tor tambroides). FISH & SHELLFISH IMMUNOLOGY 2024; 148:109518. [PMID: 38513913 DOI: 10.1016/j.fsi.2024.109518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/04/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024]
Abstract
Pseudomonas species are one of the most threatening fish pathogens which reside a wide range of environments. In this study, the dominant bacteria were isolated from diseased Malaysian mahseer (Tor tambroides) and tentatively named CM-01. It was identified as Pseudomonas koreensis based on its biochemical, morphological, genetic and physiological information. Its pathogenicity was found to be correlated with twelve virulence genes identified including iron uptake, protease, acylhomoserine lactone synthase gacS/gacA component regulation system, type IV secretion system, hydrogen cyanide production, exolysin, alginate biosynthesis, flagella and pili. The median lethal dose (LD50) for the CM-01 isolate on Malaysian mahseer was documented at 5.01 × 107 CFU/mL. The experimental infection revealed that CM-01 led to significant histological lesions in the fish, ultimately resulting in death. These lesions comprise necrosis, tissue thickening and aggregation. Drug sensitivity tests had shown its susceptibility to beta-lactam combination agents and further suggest its drug of choice. Its growing features had shown its growth at optimal temperature and pH. To the best of our knowledge, this is the first report of P. koreensis linked to diseased T. tambroides. STATEMENT OF RELEVANCE: In this research, a novel strain of Pseudomonas koreensis, CM-01 was isolated from diseased T. tambroides for the first time. The antimicrobial susceptibility, pathogenicity, virulence genes and growth characteristics of CM-01 were studied. These findings established a scientific foundation for the recognition of P. koreensis and the management of fish infections caused by this pathogen.
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Affiliation(s)
- Melinda Mei Lin Lau
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia.
| | - Cindy Jia Yung Kho
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia.
| | - Hung Hui Chung
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia.
| | - Azham Zulkharnain
- Department of Bioscience and Engineering, College of system Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama, 337-8570, Japan.
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2
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Lavado-Benito C, Murillo J, Martínez-Gil M, Ramos C, Rodríguez-Moreno L. GacA reduces virulence and increases competitiveness in planta in the tumorigenic olive pathogen Pseudomonas savastanoi pv. savastanoi. FRONTIERS IN PLANT SCIENCE 2024; 15:1347982. [PMID: 38375080 PMCID: PMC10875052 DOI: 10.3389/fpls.2024.1347982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/08/2024] [Indexed: 02/21/2024]
Abstract
GacS/GacA is a widely distributed two-component system playing an essential role as a key global regulator, although its characterization in phytopathogenic bacteria has been deeply biased, being intensively studied in pathogens of herbaceous plants but barely investigated in pathogens of woody hosts. P. savastanoi pv. savastanoi (Psv) is characterized by inducing tumours in the stem and branches of olive trees. In this work, the model strain Psv NCPPB 3335 and a mutant derivative with a complete deletion of gene gacA were subjected to RNA-Seq analyses in a minimum medium and a medium mimicking in planta conditions, accompanied by RT-qPCR analyses of selected genes and phenotypic assays. These experiments indicated that GacA participates in the regulation of at least 2152 genes in strain NCPPB 3335, representing 37.9 % of the annotated CDSs. GacA also controls the expression of diverse rsm genes, and modulates diverse phenotypes, including motility and resistance to oxidative stresses. As occurs with other P. syringae pathovars of herbaceous plants, GacA regulates the expression of the type III secretion system and cognate effectors. In addition, GacA also regulates the expression of WHOP genes, specifically encoded in P. syringe strains isolated from woody hosts, and genes for the biosynthesis of phytohormones. A gacA mutant of NCPPB 3335 showed increased virulence, producing large immature tumours with high bacterial populations, but showed a significantly reduced competitiveness in planta. Our results further extend the role of the global regulator GacA in the virulence and fitness of a P. syringae pathogen of woody hosts.
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Affiliation(s)
- Carla Lavado-Benito
- Área de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, Spain
| | - Jesús Murillo
- Institute for Multidisciplinary Research in Applied Biology, Universidad Pública de Navarra (UPNA), Edificio de Agrobiotecnología, Mutilva Baja, Spain
| | - Marta Martínez-Gil
- Área de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, Spain
| | - Luis Rodríguez-Moreno
- Área de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, Spain
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3
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He LL, Wang X, O'Neill Rothenberg D, Xu X, Wang HH, Deng X, Cui ZN. A novel strategy to control Pseudomonas syringae through inhibition of type III secretion system. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 194:105471. [PMID: 37532345 DOI: 10.1016/j.pestbp.2023.105471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 08/04/2023]
Abstract
Pseudomonas syringae (P. syringae) is a highly prevalent Gram-negative pathogen with over 60 pathogenic variants that cause yield losses of up to 80% in various crops. Traditional control methods mainly involve the application of antibiotics to inactivate pathogenic bacteria, but large-scale application of antibiotics has led to the development of bacterial resistance. Gram-negative pathogens including P. syringae commonly use the type III secretion system (T3SS) as a transport channel to deliver effector proteins into host cells, disrupting host defences and facilitating virulence, providing a novel target for antibacterial drug development. In this study, we constructed a high-throughput screening reporter system based on our previous work to screen for imidazole, oxazole and thiazole compounds. The screening indicated that the three compounds (II-14, II-15 and II-24) significantly inhibited hrpW and hrpL gene promoter activity without influencing the growth of P. syringae, and the inhibitory activity was better than that of the positive control sulforaphane (4-methylsulfinylbutyl isothiocyanate, SFN) at 50 μM. Three compounds suppressed the transcript levels of representative T3SS genes to different degrees, suggesting that the compounds may suppress the expression of T3SS by modulating the HrpR/S-HrpL regulatory pathway. Inoculation experiments indicated that all three compounds suppressed the pathogenicity of Pseudomonas syringae pv. tomato DC3000 in tomato and Pseudomonas syringae pv. phaseolicola 1448A in bean to varying degrees. One representative compound, II-15, significantly inhibited the secretion of the Pst DC3000 AvrPto effector protein. These findings provide a theoretical basis for the development of novel P. syringae T3SS inhibitors for application in disease prevention and control.
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Affiliation(s)
- Lu-Lu He
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Xin Wang
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | | | - Xiaoli Xu
- Instrumental Analysis & Research Center, South China Agricultural University, Guangzhou 510642, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
| | - Zi-Ning Cui
- National Key Laboratory of Green Pesticide, Integrative Microbiology Research Centre, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
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4
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O’Malley MR, Kpenu E, Peck SC, Anderson JC. Plant-exuded chemical signals induce surface attachment of the bacterial pathogen Pseudomonas syringae. PeerJ 2023; 11:e14862. [PMID: 37009160 PMCID: PMC10062345 DOI: 10.7717/peerj.14862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/17/2023] [Indexed: 03/29/2023] Open
Abstract
Many plant pathogenic bacteria suppress host defenses by secreting small molecule toxins or immune-suppressing proteins into host cells, processes that likely require close physical contact between pathogen and host. Yet, in most cases, little is known about whether phytopathogenic bacteria physically attach to host surfaces during infection. Here we report that Pseudomonas syringae pv. tomato strain DC3000, a Gram-negative bacterial pathogen of tomato and Arabidopsis, attaches to polystyrene and glass surfaces in response to chemical signals exuded from Arabidopsis seedlings and tomato leaves. We characterized the molecular nature of these attachment-inducing signals and discovered that multiple hydrophilic metabolites found in plant exudates, including citric acid, glutamic acid, and aspartic acid, are potent inducers of surface attachment. These same compounds were previously identified as inducers of P. syringae genes encoding a type III secretion system (T3SS), indicating that both attachment and T3SS deployment are induced by the same plant signals. To test if surface attachment and T3SS are regulated by the same signaling pathways, we assessed the attachment phenotypes of several previously characterized DC3000 mutants, and found that the T3SS master regulator HrpL was partially required for maximal levels of surface attachment, whereas the response regulator GacA, a negative regulator of T3SS, negatively regulated DC3000 surface attachment. Together, our data indicate that T3SS deployment and surface attachment by P. syringae may be co-regulated by the same host signals during infection, possibly to ensure close contact necessary to facilitate delivery of T3SS effectors into host cells.
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Affiliation(s)
- Megan R. O’Malley
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Eyram Kpenu
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
- Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Scott C. Peck
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
- Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
- Department of Biochemistry, University of Missouri, Columbia, Missouri, United States of America
| | - Jeffrey C. Anderson
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
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5
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Transcriptome analysis of sRNA responses to four different antibiotics in Pseudomonas aeruginosa PAO1. Microb Pathog 2022; 173:105865. [DOI: 10.1016/j.micpath.2022.105865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
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6
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Qiao P, Zhao M, Guan W, Walcott R, Ye Y, Yang Y, Zhao T. A putative multi-sensor hybrid histidine kinase, BarA Ac , inhibits the expression of the type III secretion system regulator HrpG in Acidovorax citrulli. Front Microbiol 2022; 13:1064577. [PMID: 36532489 PMCID: PMC9748350 DOI: 10.3389/fmicb.2022.1064577] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 11/14/2022] [Indexed: 07/30/2023] Open
Abstract
Bacterial fruit blotch (BFB), caused by Acidovorax citrulli, severely damages watermelon, melon, and other cucurbit crops worldwide. Although many virulence determinants have been identified in A. citrulli, including swimming motility, twitching motility, biofilm formation, and the type III secretion system (T3SS), research on their regulation is lacking. To study virulence regulation mechanisms, we found a putative histidine kinase BarA Ac that may be related to the T3SS regulator HrpG in A. citrulli. We deleted and characterized barAAc (Aave_2063) in A. citrulli Aac5 strain. Compared to the wild-type Aac5, virulence and early proliferation of barAAc mutant in host watermelon cotyledons were significantly increased, and induction of hypersensitive response in non-host tobacco was accelerated, while biofilm formation and swimming motility were significantly reduced. In addition, the transcriptomic analysis revealed that the expression of many T3SS-related genes was upregulated in the ΔbarAAc deletion mutant when cultured in KB medium. Meanwhile, the ΔbarAAc deletion mutant showed increased accumulation of the T3SS regulator HrpG in KB medium, which may account for the increased deployment of T3SS. This suggests that the putative histidine kinase BarA Ac is able to repress the T3SS expression by inhibiting HrpG in the KB medium, which appears to be important for rational energy allocation. In summary, our research provides further understanding of the regulatory network of A. citrulli virulence.
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Affiliation(s)
- Pei Qiao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mei Zhao
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Department of Plant Pathology, University of Georgia, Athens, GA, United States
| | - Wei Guan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ron Walcott
- Department of Plant Pathology, University of Georgia, Athens, GA, United States
| | - Yunfeng Ye
- Horticultural Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Yuwen Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Tingchang Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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7
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Shan S, Hu T, Yang Y. The deletion of HK-1 gene affects the bacterial virulence of Pseudomonas stutzeri LH-42. PLoS One 2022; 17:e0277089. [PMID: 36445858 PMCID: PMC9707753 DOI: 10.1371/journal.pone.0277089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/19/2022] [Indexed: 12/03/2022] Open
Abstract
Two-component systems (TCSs) are widespread regulatory systems in bacteria, which control cellular functions and play an important role in sensing various external stimuli and regulating gene expression in response to environmental changes. Among the nineteen genes for the two-component system found in the whole genome of Pseudomonas stutzeri LH-42, one of the TCS coded by the HK-1 gene, has a structural domain similar to the HAMP domain, which plays an important role in regulating bacterial virulence in other bacteria. In this study, the deletion mutant LH-42△HK-1 was successfully constructed using the lambda Red recombinase system. Compared with the wild-type strain, the mutant strain LH-42△HK-1 showed a significantly slower growth time and a longer stationary phase time. In addition, in the plate bacteriostatic experiment with Escherichia coli DH5α as an indicator strain, the inhibition zone size of the mutant strain showed significantly less than the wild-type strain(P<0.05), indicating that the virulence of the mutant strain was significantly reduced compared with the wild-type strain. Overall, the results indicate that the deletion of the gene HK-1 decreased bacterial virulence in Pseudomonas stutzeri LH-42.
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Affiliation(s)
- Si Shan
- School of Minerals Processing and Bioengineering, Central South University, Changsha, Hunan, China
| | - Tingting Hu
- The First People’s Hospital of Jingzhou, Jingzhou, Hubei, China
| | - Yu Yang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, Hunan, China
- Key Laboratory of Biohydrometallurgy of Ministry of Education, School of Minerals Processing and Bioengineering, Central South University, Changsha, Hunan, China
- * E-mail:
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8
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Xie Y, Li J, Ding Y, Shao X, Sun Y, Xie F, Liu S, Tang S, Deng X. An atlas of bacterial two-component systems reveals function and plasticity in signal transduction. Cell Rep 2022; 41:111502. [DOI: 10.1016/j.celrep.2022.111502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 08/11/2022] [Accepted: 09/22/2022] [Indexed: 11/03/2022] Open
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9
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Ferreiro MD, Behrmann LV, Corral A, Nogales J, Gallegos MT. Exploring the expression and functionality of the rsm sRNAs in Pseudomonas syringae pv. tomato DC3000. RNA Biol 2021; 18:1818-1833. [PMID: 33406981 PMCID: PMC8583166 DOI: 10.1080/15476286.2020.1871217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/08/2020] [Accepted: 12/29/2020] [Indexed: 12/18/2022] Open
Abstract
The Gac-rsm pathway is a global regulatory network that governs mayor lifestyle and metabolic changes in gamma-proteobacteria. In a previous study, we uncovered the role of CsrA proteins promoting growth and repressing motility, alginate production and virulence in the model phytopathogen Pseudomonas syringae pv. tomato (Pto) DC3000. Here, we focus on the expression and regulation of the rsm regulatory sRNAs, since Pto DC3000 exceptionally has seven variants (rsmX1-5, rsmY and rsmZ). The presented results offer further insights into the functioning of the complex Gac-rsm pathway and the interplay among its components. Overall, rsm expressions reach maximum levels at high cell densities, are unaffected by surface detection, and require GacA for full expression. The rsm levels of expression and GacA-dependence are determined by the sequences found in their -35/-10 promoter regions and GacA binding boxes, respectively. rsmX5 stands out for being the only rsm in Pto DC3000 whose high expression does not require GacA, constituting the main component of the total rsm pool in a gacA mutant. The deletion of rsmY and rsmZ had minor effects on Pto DC3000 motility and virulence phenotypes, indicating that rsmX1-5 can functionally replace them. On the other hand, rsmY or rsmZ overexpression in a gacA mutant did not revert its phenotype. Additionally, a negative feedback regulatory loop in which the CsrA3 protein promotes its own titration by increasing the levels of several rsm RNAs in a GacA-dependent manner has been disclosed as part of this work.
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Affiliation(s)
- María-Dolores Ferreiro
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental Del Zaidín (EEZ-CSIC), Granada, Spain
| | - Lara Vanessa Behrmann
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental Del Zaidín (EEZ-CSIC), Granada, Spain
| | - Ana Corral
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental Del Zaidín (EEZ-CSIC), Granada, Spain
| | - Joaquina Nogales
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental Del Zaidín (EEZ-CSIC), Granada, Spain
| | - María-Trinidad Gallegos
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental Del Zaidín (EEZ-CSIC), Granada, Spain
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10
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Liu W, Triplett L, Chen XL. Emerging Roles of Posttranslational Modifications in Plant-Pathogenic Fungi and Bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:99-124. [PMID: 33909479 DOI: 10.1146/annurev-phyto-021320-010948] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Posttranslational modifications (PTMs) play crucial roles in regulating protein function and thereby control many cellular processes and biological phenotypes in both eukaryotes and prokaryotes. Several recent studies illustrate how plant fungal and bacterial pathogens use these PTMs to facilitate development, stress response, and host infection. In this review, we discuss PTMs that have key roles in the biological and infection processes of plant-pathogenic fungi and bacteria. The emerging roles of PTMs during pathogen-plant interactions are highlighted. We also summarize traditional tools and emerging proteomics approaches for PTM research. These discoveries open new avenues for investigating the fundamental infection mechanisms of plant pathogens and the discovery of novel strategies for plant disease control.
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Affiliation(s)
- Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
| | - Lindsay Triplett
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, USA;
| | - Xiao-Lin Chen
- State Key Laboratory of Agricultural Microbiology and Provincial Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China;
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11
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Li E, de Jonge R, Liu C, Jiang H, Friman VP, Pieterse CMJ, Bakker PAHM, Jousset A. Rapid evolution of bacterial mutualism in the plant rhizosphere. Nat Commun 2021; 12:3829. [PMID: 34158504 PMCID: PMC8219802 DOI: 10.1038/s41467-021-24005-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 05/24/2021] [Indexed: 02/07/2023] Open
Abstract
While beneficial plant-microbe interactions are common in nature, direct evidence for the evolution of bacterial mutualism is scarce. Here we use experimental evolution to causally show that initially plant-antagonistic Pseudomonas protegens bacteria evolve into mutualists in the rhizosphere of Arabidopsis thaliana within six plant growth cycles (6 months). This evolutionary transition is accompanied with increased mutualist fitness via two mechanisms: (i) improved competitiveness for root exudates and (ii) enhanced tolerance to the plant-secreted antimicrobial scopoletin whose production is regulated by transcription factor MYB72. Crucially, these mutualistic adaptations are coupled with reduced phytotoxicity, enhanced transcription of MYB72 in roots, and a positive effect on plant growth. Genetically, mutualism is associated with diverse mutations in the GacS/GacA two-component regulator system, which confers high fitness benefits only in the presence of plants. Together, our results show that rhizosphere bacteria can rapidly evolve along the parasitism-mutualism continuum at an agriculturally relevant evolutionary timescale.
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Affiliation(s)
- Erqin Li
- grid.5477.10000000120346234Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands ,grid.14095.390000 0000 9116 4836Freie Universität Berlin, Institut für Biologie, Berlin, Germany ,grid.452299.1Berlin-Brandenburg Institute of Advanced Biodiversity Research, Berlin, Germany
| | - Ronnie de Jonge
- grid.5477.10000000120346234Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands ,grid.11486.3a0000000104788040VIB Center for Plant Systems Biology, Ghent, Belgium ,grid.5342.00000 0001 2069 7798Ghent University, Department of Plant Biotechnology and Bioinformatics, Ghent, Belgium
| | - Chen Liu
- grid.5477.10000000120346234Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
| | - Henan Jiang
- grid.5477.10000000120346234Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
| | - Ville-Petri Friman
- grid.5685.e0000 0004 1936 9668University of York, Department of Biology, York, UK
| | - Corné M. J. Pieterse
- grid.5477.10000000120346234Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
| | - Peter A. H. M. Bakker
- grid.5477.10000000120346234Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
| | - Alexandre Jousset
- grid.5477.10000000120346234Utrecht University, Department of Biology, Ecology and Biodiversity, Utrecht, The Netherlands
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12
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Li E, de Jonge R, Liu C, Jiang H, Friman VP, Pieterse CMJ, Bakker PAHM, Jousset A. Rapid evolution of bacterial mutualism in the plant rhizosphere. Nat Commun 2021. [PMID: 34158504 DOI: 10.1038/s41467-012-24005-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023] Open
Abstract
While beneficial plant-microbe interactions are common in nature, direct evidence for the evolution of bacterial mutualism is scarce. Here we use experimental evolution to causally show that initially plant-antagonistic Pseudomonas protegens bacteria evolve into mutualists in the rhizosphere of Arabidopsis thaliana within six plant growth cycles (6 months). This evolutionary transition is accompanied with increased mutualist fitness via two mechanisms: (i) improved competitiveness for root exudates and (ii) enhanced tolerance to the plant-secreted antimicrobial scopoletin whose production is regulated by transcription factor MYB72. Crucially, these mutualistic adaptations are coupled with reduced phytotoxicity, enhanced transcription of MYB72 in roots, and a positive effect on plant growth. Genetically, mutualism is associated with diverse mutations in the GacS/GacA two-component regulator system, which confers high fitness benefits only in the presence of plants. Together, our results show that rhizosphere bacteria can rapidly evolve along the parasitism-mutualism continuum at an agriculturally relevant evolutionary timescale.
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Affiliation(s)
- Erqin Li
- Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
- Freie Universität Berlin, Institut für Biologie, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, Berlin, Germany
| | - Ronnie de Jonge
- Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands.
- VIB Center for Plant Systems Biology, Ghent, Belgium.
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Ghent, Belgium.
| | - Chen Liu
- Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
| | - Henan Jiang
- Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
| | | | - Corné M J Pieterse
- Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
| | - Peter A H M Bakker
- Utrecht University, Department of Biology, Plant-Microbe Interactions, Utrecht, The Netherlands
| | - Alexandre Jousset
- Utrecht University, Department of Biology, Ecology and Biodiversity, Utrecht, The Netherlands.
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13
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O’Malley MR, Anderson JC. Regulation of the Pseudomonas syringae Type III Secretion System by Host Environment Signals. Microorganisms 2021; 9:microorganisms9061227. [PMID: 34198761 PMCID: PMC8228185 DOI: 10.3390/microorganisms9061227] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas syringae are Gram-negative, plant pathogenic bacteria that use a type III secretion system (T3SS) to disarm host immune responses and promote bacterial growth within plant tissues. Despite the critical role for type III secretion in promoting virulence, T3SS-encoding genes are not constitutively expressed by P. syringae and must instead be induced during infection. While it has been known for many years that culturing P. syringae in synthetic minimal media can induce the T3SS, relatively little is known about host signals that regulate the deployment of the T3SS during infection. The recent identification of specific plant-derived amino acids and organic acids that induce T3SS-inducing genes in P. syringae has provided new insights into host sensing mechanisms. This review summarizes current knowledge of the regulatory machinery governing T3SS deployment in P. syringae, including master regulators HrpRS and HrpL encoded within the T3SS pathogenicity island, and the environmental factors that modulate the abundance and/or activity of these key regulators. We highlight putative receptors and regulatory networks involved in linking the perception of host signals to the regulation of the core HrpRS–HrpL pathway. Positive and negative regulation of T3SS deployment is also discussed within the context of P. syringae infection, where contributions from distinct host signals and regulatory networks likely enable the fine-tuning of T3SS deployment within host tissues. Last, we propose future research directions necessary to construct a comprehensive model that (a) links the perception of host metabolite signals to T3SS deployment and (b) places these host–pathogen signaling events in the overall context of P. syringae infection.
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Ferreiro MD, Gallegos MT. Distinctive features of the Gac-Rsm pathway in plant-associated Pseudomonas. Environ Microbiol 2021; 23:5670-5689. [PMID: 33939255 DOI: 10.1111/1462-2920.15558] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 02/04/2023]
Abstract
Productive plant-bacteria interactions, either beneficial or pathogenic, require that bacteria successfully sense, integrate and respond to continuously changing environmental and plant stimuli. They use complex signal transduction systems that control a vast array of genes and functions. The Gac-Rsm global regulatory pathway plays a key role in controlling fundamental aspects of the apparently different lifestyles of plant beneficial and phytopathogenic Pseudomonas as it coordinates adaptation and survival while either promoting plant health (biocontrol strains) or causing disease (pathogenic strains). Plant-interacting Pseudomonas stand out for possessing multiple Rsm proteins and Rsm RNAs, but the physiological significance of this redundancy is not yet clear. Strikingly, the components of the Gac-Rsm pathway and the controlled genes/pathways are similar, but the outcome of its regulation may be opposite. Therefore, identifying the target mRNAs bound by the Rsm proteins and their mode of action (repression or activation) is essential to explain the resulting phenotype. Some technical considerations to approach the study of this system are also given. Overall, several important features of the Gac-Rsm cascade are now understood in molecular detail, particularly in Pseudomonas protegens CHA0, but further questions remain to be solved in other plant-interacting Pseudomonas.
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Affiliation(s)
- María-Dolores Ferreiro
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
| | - María-Trinidad Gallegos
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
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Shao X, Tan M, Xie Y, Yao C, Wang T, Huang H, Zhang Y, Ding Y, Liu J, Han L, Hua C, Wang X, Deng X. Integrated regulatory network in Pseudomonas syringae reveals dynamics of virulence. Cell Rep 2021; 34:108920. [PMID: 33789108 DOI: 10.1016/j.celrep.2021.108920] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/09/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas syringae, a Gram-negative plant pathogen, expresses multitudinous transcriptional regulators to control the type III secretion system (T3SS) and response to diverse environmental challenges. Although the mechanisms of virulence-associated regulators of P. syringae have been studied for decades, the overall crosstalk underlying these regulators is still elusive. Here, we identify five T3SS regulators (EnvZ-OmpR, CbrAB2, PhoPQ, PilRS, and MgrA), and find that the two-component systems EnvZ-OmpR and CbrAB2 negatively regulate the T3SS. To elucidate crosstalk between 16 virulence-associated regulators in P. syringae, we map an online intricate network called "PSRnet" (Pseudomonas syringae regulatory network) by combining the differentially expressed genes (DEGs) of these 16 regulators by RNA sequencing (RNA-seq) and their binding loci by chromatin immunoprecipitation sequencing (ChIP-seq). Consequently, we identify 238 and 153 functional genes involved in the T3SS and other virulence-related pathways in KB and MM media, respectively. Our results provide insights into the mechanism of plant infections caused by P. syringae.
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Affiliation(s)
- Xiaolong Shao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Miaomiao Tan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yingpeng Xie
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Chunyan Yao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Tingting Wang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Hao Huang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yingchao Zhang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Yiqing Ding
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Jingui Liu
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Liangliang Han
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Canfeng Hua
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Xin Wang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China.
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China.
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16
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Xie Y, Liu W, Shao X, Zhang W, Deng X. Signal transduction schemes in Pseudomonas syringae. Comput Struct Biotechnol J 2020; 18:3415-3424. [PMID: 33294136 PMCID: PMC7691447 DOI: 10.1016/j.csbj.2020.10.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/29/2020] [Accepted: 10/31/2020] [Indexed: 11/11/2022] Open
Abstract
To cope with their continually fluctuating surroundings, pathovars of the unicellular phytopathogen Pseudomonas syringae have developed rapid and sophisticated signalling networks to sense extracellular stimuli, which allow them to adjust their cellular composition to survive and cause diseases in host plants. Comparative genomic analyses of P. syringae strains have identified various genes that encode several classes of signalling proteins, although how this bacterium directly perceives these environmental cues remains elusive. Recent work has revealed new mechanisms of a cluster of bacterial signal transduction systems that mainly include two-component systems (such as RhpRS, GacAS, CvsRS and AauRS), extracytoplasmic function sigma factors (such as HrpL and AlgU), nucleotide-based secondary messengers, methyl-accepting chemotaxis sensor proteins and several other intracellular surveillance systems. In this review, we compile a list of the signal transduction mechanisms that P. syringae uses to monitor and respond in a timely manner to intracellular and external conditions. Further understanding of these surveillance processes will provide new perspectives from which to combat P. syringae infections.
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Affiliation(s)
- Yingpeng Xie
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region
| | - Wenbao Liu
- College of Agricultural Sciences and Technology, Shandong Agriculture and Engineering University, Jinan 250100, China
| | - Xiaolong Shao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region
| | - Weihua Zhang
- Institute of Vegetables and Flowers, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region.,Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
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Latour X. The Evanescent GacS Signal. Microorganisms 2020; 8:microorganisms8111746. [PMID: 33172195 PMCID: PMC7695008 DOI: 10.3390/microorganisms8111746] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 12/18/2022] Open
Abstract
The GacS histidine kinase is the membrane sensor of the major upstream two-component system of the regulatory Gac/Rsm signal transduction pathway. This pathway governs the expression of a wide range of genes in pseudomonads and controls bacterial fitness and motility, tolerance to stress, biofilm formation, and virulence or plant protection. Despite the importance of these roles, the ligands binding to the sensor domain of GacS remain unknown, and their identification is an exciting challenge in this domain. At high population densities, the GacS signal triggers a switch from primary to secondary metabolism and a change in bacterial lifestyle. It has been suggested, based on these observations, that the GacS signal is a marker of the emergence of nutritional stress and competition. Biochemical investigations have yet to characterize the GacS signal fully. However, they portray this cue as a low-molecular weight, relatively simple and moderately apolar metabolite possibly resembling, but nevertheless different, from the aliphatic organic acids acting as quorum-sensing signaling molecules in other Proteobacteria. Significant progress in the development of metabolomic tools and new databases dedicated to Pseudomonas metabolism should help to unlock some of the last remaining secrets of GacS induction, making it possible to control the Gac/Rsm pathway.
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Affiliation(s)
- Xavier Latour
- Laboratory of Microbiology Signals and Microenvironment (LMSM EA 4312), Normandy University (University of Rouen Normandy), 55 rue Saint-Germain, 27000 Evreux, France;
- Research Federation NORVEGE Fed4277, Normandy University, F-76821 Mont-Saint-Aignan, France
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Two Homologues of the Global Regulator Csr/Rsm Redundantly Control Phaseolotoxin Biosynthesis and Virulence in the Plant Pathogen Pseudomonas amygdali pv. phaseolicola 1448A. Microorganisms 2020; 8:microorganisms8101536. [PMID: 33036191 PMCID: PMC7600136 DOI: 10.3390/microorganisms8101536] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 12/16/2022] Open
Abstract
The widely conserved Csr/Rsm (carbon storage regulator/repressor of stationary-phase metabolites) post-transcriptional regulatory system controls diverse phenotypes involved in bacterial pathogenicity and virulence. Here we show that Pseudomonas amygdali pv. phaseolicola 1448A contains seven rsm genes, four of which are chromosomal. In RNAseq analyses, only rsmE was thermoregulated, with increased expression at 18 °C, whereas the antagonistic sRNAs rsmX1, rsmX4, rsmX5 and rsmZ showed increased levels at 28 °C. Only double rsmA-rsmE mutants showed significantly altered phenotypes in functional analyses, being impaired for symptom elicitation in bean, including in planta growth, and for induction of the hypersensitive response in tobacco. Double mutants were also non-motile and were compromised for the utilization of different carbon sources. These phenotypes were accompanied by reduced mRNA levels of the type III secretion system regulatory genes hrpL and hrpA, and the flagellin gene, fliC. Biosynthesis of the phytotoxin phaseolotoxin by mutants in rsmA and rsmE was delayed, occurring only in older cultures, indicating that these rsm homologues act as inductors of toxin synthesis. Therefore, genes rsmA and rsmE act redundantly, although with a degree of specialization, to positively regulate diverse phenotypes involved in niche colonization. Additionally, our results suggest the existence of a regulatory molecule different from the Rsm proteins and dependent on the GacS/GacA (global activator of antibiotic and cyanide production) system, which causes the repression of phaseolotoxin biosynthesis at high temperatures.
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Re-evaluation of a Tn5::gacA mutant of Pseudomonas syringae pv. tomato DC3000 uncovers roles for uvrC and anmK in promoting virulence. PLoS One 2019; 14:e0223637. [PMID: 31600319 PMCID: PMC6786584 DOI: 10.1371/journal.pone.0223637] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 09/25/2019] [Indexed: 12/16/2022] Open
Abstract
Pseudomonas syringae is a taxon of plant pathogenic bacteria that can colonize and proliferate within the interior space of leaf tissue. This process requires P. syringae to rapidly upregulate the production of virulence factors including a type III secretion system (T3SS) that suppress host defenses. GacS/A is a two-component system that regulates virulence of many plant and animal pathogenic bacteria including P. syringae. We recently investigated the virulence defect of strain AC811, a Tn5::gacA mutant of P. syringae pv. tomato DC3000 that is less virulent on Arabidopsis. We discovered that decreased virulence of AC811 is not caused by loss of GacA function. Here, we report the molecular basis of the virulence defect of AC811. We show that AC811 possesses a nonsense mutation in anmK, a gene predicted to encode a 1,6-anhydromuramic acid kinase involved in cell wall recycling. Expression of a wild-type allele of anmK partially increased growth of AC811 in Arabidopsis leaves. In addition to the defective anmK allele, we also show that the Tn5 insertion in gacA exerts a polar effect on uvrC, a downstream gene encoding a regulator of DNA damage repair. Expression of the wild-type anmK allele together with increased expression of uvrC fully restored the virulence of AC811 during infection of Arabidopsis. These results demonstrate that defects in anmK and uvrC are together sufficient to account for the decreased virulence of AC811, and suggest caution is warranted in assigning phenotypes to GacA function based on insertional mutagenesis of the gacA-uvrC locus.
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20
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O'Malley MR, Weisberg AJ, Chang JH, Anderson JC. Re-evaluation of a Tn5::gacA mutant of Pseudomonas syringae pv. tomato DC3000 uncovers roles for uvrC and anmK in promoting virulence. PLoS One 2019; 14:e0223637. [PMID: 31600319 DOI: 10.1101/774711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 09/25/2019] [Indexed: 05/20/2023] Open
Abstract
Pseudomonas syringae is a taxon of plant pathogenic bacteria that can colonize and proliferate within the interior space of leaf tissue. This process requires P. syringae to rapidly upregulate the production of virulence factors including a type III secretion system (T3SS) that suppress host defenses. GacS/A is a two-component system that regulates virulence of many plant and animal pathogenic bacteria including P. syringae. We recently investigated the virulence defect of strain AC811, a Tn5::gacA mutant of P. syringae pv. tomato DC3000 that is less virulent on Arabidopsis. We discovered that decreased virulence of AC811 is not caused by loss of GacA function. Here, we report the molecular basis of the virulence defect of AC811. We show that AC811 possesses a nonsense mutation in anmK, a gene predicted to encode a 1,6-anhydromuramic acid kinase involved in cell wall recycling. Expression of a wild-type allele of anmK partially increased growth of AC811 in Arabidopsis leaves. In addition to the defective anmK allele, we also show that the Tn5 insertion in gacA exerts a polar effect on uvrC, a downstream gene encoding a regulator of DNA damage repair. Expression of the wild-type anmK allele together with increased expression of uvrC fully restored the virulence of AC811 during infection of Arabidopsis. These results demonstrate that defects in anmK and uvrC are together sufficient to account for the decreased virulence of AC811, and suggest caution is warranted in assigning phenotypes to GacA function based on insertional mutagenesis of the gacA-uvrC locus.
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Affiliation(s)
- Megan R O'Malley
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon, United States of America
| | - Jeffrey C Anderson
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
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