拟南芥钙依赖蛋白激酶调控植保素合成及转运的分子机制

钙(Ca2+)是植物免疫应答过程中的重要信号分子。钙依赖蛋白激酶作为胞内Ca2+感受器，在介导植物免疫信号传导过程中发挥重要作用，但其调控哪些抗病反应及相应调控机制还很不清楚。最近，我们初步研究表明，拟南芥钙依赖蛋白激酶CPK5和CPK6调控植保素camalexin的合成及转运，但其中的调控机制有待研究。本项目拟鉴定CPK5/CPK6下游调控camalexin合成及转运的关键转录因子，并解析CPK5/CPK6介导的磷酸化修饰调控下游转录因子活性的机制，同时研究CPK5/CPK6和已知的丝裂原活化蛋白激酶MPK3/MPK6如何协同调控camalexin的合成与转运，旨在全面揭示CPK5/CPK6调控camalexin合成及转运的分子机制，将大大促进我们认识钙依赖蛋白激酶在植物抗病应答过程中的功能及作用机制。近几年，申请人在植物蛋白激酶的功能研究方面已取得较显著的成果，为本项目奠定了基础。

Calcium (Ca2+) is an important signaling molecule in plant immune responses. As cytoplastic calcium sensors, calcium-dependent protein kinases (CDPKs) play fundamental roles in plant immune signal transduction. However, the downstream defense responses regulated by CDPKs and the regulation mechanisms are largely unknown. Recently, our preliminary data indicate that the Arabidopsis CDPKs CPK5 and CPK6 regulate the biosynthesis and transport of the phytoalexin camalexin, but the underlying mechanisms remain to be studied. In this proposal, we will identify the key transcription factor downstream of CPK5/CPK6 in regulating camalexin biosynthesis and transport. We will also elucidate how CPK5/CPK6-mediated phosphorylation regulates the activity of the identified transcription factor. Furthermore, we will study how CPK5/CPK6 and the mitogen-activated protein kinases MPK3/MPK6 synergistically regulate camalexin biosynthesis and transport. This project aims to uncover the molecular mechanism of CPK5/CPK6-regulated camalexin biosynthesis and transport, and will significantly advance our understanding of CDPK functions in plant immunity. The applicant has productive publications in the study of plant protein kinases during the past several years, which will facilitate the research in this project.