Ca2+/CaM在细菌N-酰基高丝氨酸内酯调控植物抗病免疫反应中的功能分析

Plant disease is one of the main factor affecting crop yield. Development of new plant immune activators is great importance of reducing the application of chemical pesticides and guaranteeing the safety of food and environment. N-acyl-homoserine lactone (AHL) is the quorum sensing signal molecule utilized by gram negative bacterium. Recent study shows that AHL can activate plant immune defense system and enhance the plant disease resistance. However, little is known about the mechanism of plant to percept AHL and trigger the immune defense system. Our previous study showed that the level of cellular Ca2+ and salicylic acid (SA) were increased by AHL in Arabidopsis. CaM was confirmed to involve in Arabidopsis cellular reaction induced by AHL. Based on our previous study, this study is to perform the functional analysis of Ca2+/CaM on SA biosynthesis and disease resistance induced by AHL in plant. The specificity of CaM isoform in involvment in plant disease resistance modulated by AHL will be addressed. The regulation network of AHL-Ca2+/CaM-SA signaling in plant defense response will be investigated. This project will lay a theoretical foundation for the development of new biocontrol strategies and plant immune activator products.

植物病害是使农作物减产的主要因素之一，研究和开发新型植物抗病免疫激活剂是生物防治的重点发展方向，对于减少化学农药的使用，保障粮食安全、生态环境安全具有重要意义。N-酰基高丝氨酸内酯（AHL）是革兰氏阴性细菌分泌的群体感应信号分子。近年研究表明AHL可以激活植物自身免疫抗病机制，提高植物抗病性。但对于植物如何感应AHL，进而启动免疫防卫系统的分子机制还很不清楚。我们前期研究表明AHL诱导拟南芥细胞外Ca2+内流、胞内SA升高，CaM参与AHL对拟南芥细胞反应的调控。本项目在此基础上，采用药理学、细胞生物学和分子遗传学等方法研究Ca2+/CaM在AHL诱导植物SA合成、调控植物免疫抗性中的功能及其调节机制，研究不同CaM亚型参与3OC8-HSL调控植物抗病性的特异性，构建AHL-Ca2+/CaM-SA调节植物免疫抗性的调控网络，为开发新型植物抗病免疫诱导技术和产品奠定理论基础。

N-酰基高丝氨酸内酯（AHL）是革兰氏阴性细菌分泌的群体感应信号分子。近年研究表明AHL可以激活植物自身免疫抗病机制，提高植物抗病性。但对于植物如何感应AHL，进而启动免疫防卫系统的分子机制还很不清楚。我们分析了AHL对植物细胞Ca2+、cAMP水平的诱导，分析了G蛋白信号系统、cAMP信号系统、Ca2+/CAM信号系统和SA信号系统中各关键信号组分在AHL调控植物抗病性中的作用，发现AHL通过激活SA的生物合成及其抗病信号途径增强植物抗病性；AHL诱导植物细胞Ca2+水平升高，GCR2和G蛋白介导AHL对Ca2+的诱导；AHL能够诱导拟南芥细胞腺苷酸环化酶AC活性和cAMP水平升高，G蛋白介导AHL对AC和cAMP的诱导；CNGC2/ Ca2+正调控AHL诱导的植物抗病性；CAM在AHL诱导植物抗病性中发挥重要作用，其中CAM1和CAM2在其中起着关键作用；CAM结合蛋白CBP60G通过调控SA途径参与AHL抗病反应；构建了AHL-Gα-cAMP-CGNC2-Ca2+-CaM-CBP60G-SA调节植物免疫抗性的调控网络，初步解析AHL诱导植物抗病的分子机制，为开发新型植物抗病免疫诱导技术和产品奠定理论基础。