The Plant Pathology Journal

The Korean Society of Plant Pathology (한국식물병리학회)
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Disruption of the metC Gene Affects Methionine Biosynthesis in Pectobacterium carotovorum subsp. carotovorum Pcc21 and Reduces Soft-Rot Disease

  • Seonmi, Yu (Department of Food Science and Biotechnology, CHA University) ;
  • Jihee, Kang (Department of Food Science and Biotechnology, CHA University) ;
  • Eui-Hwan, Chung (Department of Plant Biotechnology, Korea University) ;
  • Yunho, Lee (Department of Food Science and Biotechnology, CHA University)
  • Received : 2022.09.20
  • Accepted : 2022.11.28
  • Published : 2023.02.01
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Abstract

Plant pathogenic Pectobacterium species cause severe soft rot/blackleg diseases in many economically important crops worldwide. Pectobacterium utilizes plant cell wall degrading enzymes (PCWDEs) as the main virulence determinants for its pathogenicity. In this study, we screened a random mutant, M29 is a transposon insertion mutation in the metC gene encoding cystathionine β-lyase that catalyzes cystathionine to homocysteine at the penultimate step in methionine biosynthesis. M29 became a methionine auxotroph and resulted in growth defects in methionine-limited conditions. Impaired growth was restored with exogenous methionine or homocysteine rather than cystathionine. The mutant exhibited reduced soft rot symptoms in Chinese cabbages and potato tubers, maintaining activities of PCWDEs and swimming motility. The mutant was unable to proliferate in both Chinese cabbages and potato tubers. The reduced virulence was partially restored by a complemented strain or 100 µM of methionine, whereas it was fully restored by the extremely high concentration (1 mM). Our transcriptomic analysis showed that genes involved in methionine biosynthesis or transporter were downregulated in the mutant. Our results demonstrate that MetC is important for methionine biosynthesis and transporter and influences its virulence through Pcc21 multiplication in plant hosts.

Keywords

Acknowledgement

We are very grateful to Kyung Hye Lee and Hee Yeon Kim for their technical support and helpful comments. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (Y.L: 2018R1D1A1A02085563) funded by the Ministry of Education, Republic of Korea, Korea University Grant (E.-H.C: K2021521 and K2106871), and the BK21 FOUR program (E.-H.C: 4299991014324).

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