Identification of the interactinng proteins to clarify the molecular function of a virulence factor, Rbf1, in the rice blast fungus

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05664
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39040:Plant protection science-related
• Research Institution: National Agriculture and Food Research Organization
• Principal Investigator: Nishizawa Yoko 国立研究開発法人農業・食品産業技術総合研究機構, 生物機能利用研究部門, ユニット長 (40355756)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: いもち病菌 / イネ / 病原性

Outline of Final Research Achievements

To elucidate the mechanism of the action the Rbf1 protein, which is specifically secreted from the rice blast fungus at the penetration stage, we analyzed the site of its action. We prepared the transgenic rice plants that expectedly accumulated Rbf1 in the intercellular spaces or the cytoplasm, and we evaluated their blast disease resistance. As a result, the rice plants introduced with the RBF1 gene with the secretion signal sequence showed significantly reduced resistance. The data suggested that Rbf1 functions at the intercellular spaces between rice and the blast fungus.
Next, we analyzed the expression of 10 chitin-elicitor-responsive genes using the transformed cell lines. The expression patterns induced after chitin-elicitor treatment were similar to that of the control line regardless of the presence or absence of the secretion signal sequence in the introduced RBF1 gene. Thus, it was unlikely that Rbf1 directly acts on the expression of rice disease responsive genes.

Free Research Field

植物感染生理学

Academic Significance and Societal Importance of the Research Achievements

いもち病はイネだけでなく、近年はコムギでの被害が拡大するなど、依然として防除すべき重要病害であるため、半活物寄生菌であるいもち病菌の感染機構を分子レベルで理解することは学術的のみならず経済的にも重要である。いもち病菌の病原力に大きな影響を及ぼす感染時特異的発現タンパク質Rbf1がイネ細胞内ではなく、イネ組織に侵入したいもち病菌糸の周辺で機能することを示唆した本研究成果は、今後の防除法の開発研究に資すると考えられる。