Regulatory mechanisms on an inductive production of flavonoid-type phytoalexin in rice

2016 Fiscal Year Final Research Report

• Project/Area Number: 26450136
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Bioorganic chemistry
• Research Institution: The University of Tokyo
• Principal Investigator: Okada Kazunori 東京大学, 生物生産工学研究センター, 准教授 (20312241)
• Co-Investigator(Renkei-kenkyūsha): HAMADA KOICHI 昭和薬科大学, 薬学系, 助教 (00343070)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 転写因子 / 二次代謝産物 / イネ / フラボノイド / ファイトアレキシン / ジャスモン酸

Outline of Final Research Achievements

Biosynthesis of sakuranetin, a flavonoid phytoalexin producedin rice, is highly dependent on jasmonic acid (JA) signalling. We previously identified OsNOMT, which encodes naringenin 7-O-methyltransferase (NOMT), is a key gene for sakuranetin production, but the regulation mechanism activating the sakuranetin production was unclear. This study showed that JA-inducible bHLH-type transcriptional factor OsMYC2 drastically enhances the activity of the OsNOMT promoter and is essential for JA-inducible sakuranetin production. Besides, we identified 2 interactors of OsMYC2, OsMYC2-like protein 1 and 2 (OsMYL1 and OsMYL2) that further activated the OsNOMT promoter in synergy with OsMYC2 via their physical interaction. Our results indicate that JA signalling via OsMYC2 is reinforced by OsMYL1 and OsMYL2, resulting in the inductive production of sakuranetin during defence responses in rice.

Free Research Field

植物分子生物学