Analysis of the rice immune system regulated by phytocytokines

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K14856
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 39040:Plant protection science-related
• Research Institution: Okayama University
• Principal Investigator: Fukada Fumi 岡山大学, 資源植物科学研究所, 特任助教 (80740414)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ペプチド / RALF / イネ / 免疫 / イネいもち病菌 / ROS

Outline of Final Research Achievements

Plants regulate the immunity through secretion of phytocytokines, endogenous hormone-like peptides, after recognition of the plant pathogen invasion. The functional characterization of phytocytokines
can be beneficial for agronomical usage because many phytocytokines studied so far are highly active at a low concentration and play important roles in the regulation of plant development, reproduction, immunity, and adaptation to environmental stresses. However, the mode of action of phytocytokines in crops are largely lacking. In this study, we functionally characterized the mechanism on how phytocytokine RALF7 in rice regulates immunity after infection of rice blast fungus. We showed that RALF7 induces chitin-triggered immunity through its specific receptor. The candidate genes that are regulated by RALF7-receptor pair were also identified by RNAseq analysis.

Free Research Field

植物病理学

Academic Significance and Societal Importance of the Research Achievements

本研究では、穀物でほぼ未知であった植物サイトカインの作用機序に着目し、イネにおける植物サイトカインRALF7とその受容体の同定による免疫制御機構を明らかにすることで、学術的に重要な知見を得た。植物サイトカインは微量で生理活性を示すことから、その有効性が期待されるが、実際にRALF7ペプチド処理により、イネは直ちに免疫応答を活性化させ、植物病原菌に対する抵抗性に寄与することが明らかとなった。このことから、本研究を基盤に、生理活性の高いRALF7ペプチドの開発、効率的なペプチドの合成系、圃場での有効性が確立できれば、RALF7ペプチドを用いた穀物の耐病性の向上が期待される。