Molecular mechanism for activation of Ralstonia solanacearum type III effector RipAY in plant cells

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K07320
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Plant protection science
• Research Institution: 岡山県農林水産総合センター生物科学研究所
• Principal Investigator: MUKAIHARA Takafumi 岡山県農林水産総合センター生物科学研究所, その他部局等, 専門研究員 (80344406)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: エフェクター / グルタチオン / 植物免疫 / 青枯病 / チオレドキシン

Outline of Final Research Achievements

Ralstonia solanacearum injects virulence effector proteins into plant cells to succeed in infection. One of the effector proteins, RipAY, was found to function as a γ-glutamyl cyclotransferase, which degrade glutathione (GSH), a tripeptide that plays important roles in the plant immune system. The in vitro GSH degradation activity of RipAY is specifically activated by eukaryotic factors in the yeast and plant extracts. Interestingly, RipAY was activated by plant h-type thioredoxins that exist in large amounts in the plant cytosol in a thiol-independent manner. On the other hand, RipAY was not activated by bacterial thioredoxins. The high GSH degradation activity of RipAY is sufficient to suppress plant immunity during infection. However, GSH plays important roles in bacterial tolerance to various stresses and growth. The specific activation of RipAY in plant cells may be developed to prevent unwanted firing of its enzyme activity in bacterial cells.

Free Research Field

植物病理