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Heo L, Han Y, Cho Y, Choi J, Lee J, Han SW. A putative glucose 6-phosphate isomerase has pleiotropic functions on virulence and other mechanisms in Acidovorax citrulli. FRONTIERS IN PLANT SCIENCE 2023; 14:1275438. [PMID: 38023913 PMCID: PMC10664246 DOI: 10.3389/fpls.2023.1275438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023]
Abstract
Acidovorax citrulli (Ac) is a causal agent of watermelon bacterial fruit blotch (BFB) disease. Because resistance cultivars/lines have not yet been developed, it is imperative to elucidate Ac's virulence factors and their mechanisms to develop resistant cultivars/lines in different crops, including watermelon. The glucose-6-phosphate isomerase (GPI) is a reversible enzyme in both glycolysis and gluconeogenesis pathways in living organisms. However, the functions of GPI are not characterized in Ac. In this study, we determined the roles of GpiAc (GPI in Ac) by proteomic and phenotypic analyses of the mutant lacking GPI. The mutant displayed significantly reduced virulence to watermelon in two different virulence assays. The mutant's growth patterns were comparable to the wild-type strain in rich medium and M9 with glucose but not with fructose. The comparative proteome analysis markedly identified proteins related to virulence, motility, and cell wall/membrane/envelope. In the mutant, biofilm formation and twitching halo production were reduced. We further demonstrated that the mutant was less tolerant to osmotic stress and lysozyme treatment than the wild-type strain. Interestingly, the tolerance to alkali conditions was remarkably enhanced in the mutant. These results reveal that GpiAc is involved not only in virulence and glycolysis/gluconeogenesis but also in biofilm formation, twitching motility, and tolerance to diverse external stresses suggesting the pleiotropic roles of GpiAc in Ac. Our study provides fundamental and valuable information on the functions of previously uncharacterized glucose 6-phosphate isomerase and its virulence mechanism in Ac.
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Affiliation(s)
| | | | | | | | | | - Sang-Wook Han
- Department of Plant Science and Technology, Chung-Ang University, Anseong, Republic of Korea
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Rahimi-Midani A, Kim MJ, Choi TJ. Identification of a Cupin Protein Gene Responsible for Pathogenicity, Phage Susceptibility and LPS Synthesis of Acidovorax citrulli. THE PLANT PATHOLOGY JOURNAL 2021; 37:555-565. [PMID: 34897248 PMCID: PMC8666233 DOI: 10.5423/ppj.oa.08.2021.0134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/12/2021] [Indexed: 05/12/2023]
Abstract
Bacteriophages infecting Acidovorax citrulli, the causal agent of bacterial fruit blotch, have been proven to be effective for the prevention and control of this disease. However, the occurrence of bacteriophage-resistant bacteria is one of hurdles in phage biocontrol and the understanding of phage resistance in this bacterium is an essential step. In this study, we aim to investigate possible phage resistance of A. citrulli and relationship between phage resistance and pathogenicity, and to isolate and characterize the genes involved in these phenomena. A phage-resistant and less-virulent mutant named as AC-17-G1 was isolated among 3,264 A. citrulli Tn5 mutants through serial spot assays and plaque assays followed by pathogenicity test using seed coating method. The mutant has the integrated Tn5 in the middle of a cupin protein gene. This mutant recovered its pathogenicity and phage sensitivity by complementation with corresponding wild-type gene. Site-directed mutation of this gene from wild-type by CRISPR/Cas9 system resulted in the loss of pathogenicity and acquisition of phage resistance. The growth of AC-17-G1 in King's B medium was much less than the wild-type, but the growth turned into normal in the medium supplemented with D-mannose 6-phosphate or D-fructose 6-phosphate indicating the cupin protein functions as a phosphomannos isomerase. Sodium dodecyl sulfa analysis of lipopolysaccharide (LPS) extracted from the mutant was smaller than that from wild-type. All these data suggest that the cupin protein is a phosphomannos isomerase involved in LPS synthesis, and LPS is an important determinant of pathogenicity and phage susceptibility of A. citrulli.
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Affiliation(s)
| | - Min-Jung Kim
- Department of Microbiology, Pukyong National University, Busan 48513,
Korea
| | - Tae-Jin Choi
- Department of Microbiology, Pukyong National University, Busan 48513,
Korea
- Division of Marine Biosciences, Pukyong National University, Busan 48513,
Korea
- Corresponding author: Phone) +82-51-620-6367, FAX) +82-51-611-6358, E-mail)
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Zhang M, Wang X, Ahmed T, Liu M, Wu Z, Luo J, Tian Y, Jiang H, Wang Y, Sun G, Li B. Identification of Genes Involved in Antifungal Activity of Burkholderia seminalis Against Rhizoctonia solani Using Tn5 Transposon Mutation Method. Pathogens 2020; 9:pathogens9100797. [PMID: 32992669 PMCID: PMC7600168 DOI: 10.3390/pathogens9100797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/13/2022] Open
Abstract
Rhizoctonia solani is the causative agent of rice sheath blight disease. In a previous study, we found that the growth of R. solani was inhibited by Burkholderia seminalis strain R456. Therefore, the present study was conducted to identify the genes involved in the antifungal activity of B. seminalis strain R456 by using a Tn5 transposon mutation method. Firstly, we constructed a random insertion transposon library of 997 mutants, out of which 11 mutants showed the defective antifungal activity against R. solani. Furthermore, the 10 antagonism-related genes were successfully identified based on analysis of the Tn5 transposon insertion site. Indeed, this result indicated that three mutants were inserted on an indigenous plasmid in which the same insertion site was observed in two mutants. In addition, the remaining eight mutants were inserted on different genes encoding glycosyl transferase, histone H1, nonribosomal peptide synthetase, methyltransferase, MnmG, sulfate export transporter, catalase/peroxidase HPI and CysD, respectively. Compared to the wild type, the 11 mutants showed a differential effect in bacteriological characteristics such as cell growth, biofilm formation and response to H2O2 stress, revealing the complexity of action mode of these antagonism-related genes. However, a significant reduction of cell motility was observed in the 11 mutants compared to the wild type. Therefore, it can be inferred that the antifungal mechanism of the 10 above-mentioned genes may be, at least partially, due to the weakness of cell motility. Overall, the result of this study will be helpful for us to understand the biocontrol mechanism of this bacterium.
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Affiliation(s)
- Muchen Zhang
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.Z.); (X.W.); (T.A.); (M.L.); (Z.W.); (Y.T.); (H.J.)
| | - Xiaoxuan Wang
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.Z.); (X.W.); (T.A.); (M.L.); (Z.W.); (Y.T.); (H.J.)
| | - Temoor Ahmed
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.Z.); (X.W.); (T.A.); (M.L.); (Z.W.); (Y.T.); (H.J.)
| | - Mengju Liu
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.Z.); (X.W.); (T.A.); (M.L.); (Z.W.); (Y.T.); (H.J.)
| | - Zhifeng Wu
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.Z.); (X.W.); (T.A.); (M.L.); (Z.W.); (Y.T.); (H.J.)
| | - Jinyan Luo
- Department of Plant Quarantine, Shanghai Extension and Service Center of Agriculture Technology, Shanghai 201103, China;
| | - Ye Tian
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.Z.); (X.W.); (T.A.); (M.L.); (Z.W.); (Y.T.); (H.J.)
| | - Hubiao Jiang
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.Z.); (X.W.); (T.A.); (M.L.); (Z.W.); (Y.T.); (H.J.)
| | - Yanli Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China;
- Correspondence: (Y.W.); (B.L.); Tel.: +86-0571-88982412 (Y.W. & B.L.)
| | - Guochang Sun
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China;
| | - Bin Li
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (M.Z.); (X.W.); (T.A.); (M.L.); (Z.W.); (Y.T.); (H.J.)
- Correspondence: (Y.W.); (B.L.); Tel.: +86-0571-88982412 (Y.W. & B.L.)
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Identification and characterization of virulence-attenuated mutants in Ralstonia solanacearum as potential biocontrol agents against bacterial wilt of Pogostemon cablin. Microb Pathog 2020; 147:104418. [PMID: 32739402 DOI: 10.1016/j.micpath.2020.104418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/30/2020] [Accepted: 07/23/2020] [Indexed: 12/31/2022]
Abstract
Ralstonia solanacearum is a soil-borne pathogen that causes bacterial wilt worldwide. The virulence-attenuated mutants were able to combat the soil-borne plant diseases. In this study, we screened the virulence-attenuated mutant PRS-84-4-49 of Ralstonia solanacearum and demonstrated that this strain showed a significant biocontrol effect against patchouli bacterial wilt. Three putative virulence-attenuated mutants obtained in our previous preliminary screen were individually tested for their pathogenicity to patchouli plants. Mutant PRS-84-4-49 showed significantly less virulence to patchouli plants than the other investigated mutants. The virulence-attenuated mutant PRS-84-4-49 was then evaluated for its potential to control patchouli bacterial wilt. The results revealed that the biocontrol treatment significantly reduced disease severity compared with the inoculated control plants, their highest disease incidence were 33% and 63%, respectively, at 5 days post-inoculation. Mutant PRS-84-4-49 exhibited less motility and produced fewer biofilms than the wild-type strain. Therefore, our results demonstrate that virulence-attenuated mutant of Ralstonia solanacearum has potential as biological control agent capable of suppressing patchouli bacterial wilt.
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Liu J, Tian Y, Zhao Y, Zeng R, Chen B, Hu B, Walcott RR. Ferric Uptake Regulator (FurA) is Required for Acidovorax citrulli Virulence on Watermelon. PHYTOPATHOLOGY 2019; 109:1997-2008. [PMID: 31454303 DOI: 10.1094/phyto-05-19-0172-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Acidovorax citrulli is the causal agent of bacterial fruit blotch, a serious threat to commercial watermelon and melon crop production worldwide. Ferric uptake regulator (Fur) is a global transcription factor that affects a number of virulence-related functions in phytopathogenic bacteria; however, the role of furA has not been determined for A. citrulli. Hence, we constructed an furA deletion mutant and a corresponding complement in the background of A. citrulli strain xlj12 to investigate the role of the gene in siderophore production, concentration of intracellular Fe2+, bacterial sensitivity to hydrogen peroxide, biofilm formation, swimming motility, hypersensitive response induction, and virulence on melon seedlings. The A. citrulli furA deletion mutant displayed increased siderophore production, intracellular Fe2+ concentration, and increased sensitivity to hydrogen peroxide. In contrast, biofilm formation, swimming motility, and virulence on melon seedlings were significantly reduced in the furA mutant. As expected, complementation of the furA deletion mutant restored all phenotypes to wild-type levels. In accordance with the phenotypic results, the expression levels of bfrA and bfrB that encode bacterioferritin, sodB that encodes iron/manganese superoxide dismutase, fliS that encodes a flagellar protein, hrcN that encodes the type III secretion system (T3SS) ATPase, and hrcC that encodes the T3SS outer membrane ring protein were significantly downregulated in the A. citrulli furA deletion mutant. In addition, the expression of feo-related genes and feoA and feoB was significantly upregulated in the furA mutant. Overall, these results indicated that, in A. citrulli, FurA contributes to the regulation of the iron balance system, and affects a variety of virulence-related traits.
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Affiliation(s)
- Jun Liu
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanli Tian
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuqiang Zhao
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China
| | - Rong Zeng
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Baohui Chen
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Baishi Hu
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China
| | - Ron R Walcott
- Department of Plant Pathology, 4315 Miller Plant Sciences, the University of Georgia, Athens, GA 30602, U.S.A
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Wang Y, Zhang Y, Jin H, Deng Z, Li Z, Mai Y, Li G, He H. A practical random mutagenesis system for Ralstonia solanacearum strains causing bacterial wilt of Pogostemon cablin using Tn5 transposon. World J Microbiol Biotechnol 2018; 35:7. [PMID: 30565199 DOI: 10.1007/s11274-018-2581-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 12/11/2018] [Indexed: 11/26/2022]
Abstract
A practical random mutagenesis system of Ralstonia solanacearum by electroporation with Tn5 transposon was established, which may be utilized to provide genetic approach to study virulence genes of R. solanacearum strains and create nonpathogenic mutants for biological control of bacterial wilt in Pogostemon cablin. R. solanacearum strain PRS-84 used in this study was isolated from P. cablin plants infected with bacterial wilt. The bacterial suspension of R. solanacearum strain PRS-84 was mixed with Tn5 transposome complex and the mixture was transformed by electroporation. The electroporated cells were then spread on the 2, 3, 5-triphenyltetrazolium chloride agar plates containing kanamycin to select the kanamycin-resistant colonies. Several factors which determined the bacterial transformation efficiency were optimized. The transformation process was shown to be optimal at the electric field strength of 12.5 kV cm-1. Bacterial cells harvested at mid-exponential phase gave the highest transformation efficiency. 10 µg mL-1 kanamycin was found to be the optimal concentration for transformant selection. Tn5 insertion mutants of R. solanacearum strain PRS-84 were identified by PCR amplification and Southern blot analysis. Mutants subcultured for 100 passages were also detected by PCR amplification and Southern blot analysis. Furthermore, pathogenicity screening test of mutants was performed by inoculating in vitro regenerated patchouli plants. Results revealed that mutants with a single Tn5 insertion in their genomes were obtained from R. solanacearum strain PRS-84, and the Tn5 insertion could be stably inherited in the mutants. Then, mutants with reduced pathogenicity were selected.
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Affiliation(s)
- Yaqin Wang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, 232 WaiHuan East Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, People's Republic of China
| | - Yuyao Zhang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, 232 WaiHuan East Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, People's Republic of China
| | - Hua Jin
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, 232 WaiHuan East Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, People's Republic of China
| | - Zhicheng Deng
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, 232 WaiHuan East Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, People's Republic of China
| | - Zhuan Li
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, 232 WaiHuan East Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, People's Republic of China
| | - Yanzhen Mai
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, 232 WaiHuan East Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, People's Republic of China
| | - Guangwei Li
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, 232 WaiHuan East Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, People's Republic of China
| | - Hong He
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, 232 WaiHuan East Road, Guangzhou Higher Education Mega Center, Guangzhou, 510006, People's Republic of China.
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