胞吐复合体负责将高尔基囊泡靶向拴系到细胞质膜上，是囊泡运输过程的关键步骤。拟南芥胞吐复合体成员EXO70B1通过调节FLS2 (FLAGELLIN SENSING 2)等模式识别受体在细胞膜表面富集正调控植物免疫反应。功能缺失突变体exo70B1表现出自发的细胞死亡和增强的抗病性，其抗病表型依赖于非典型NLR蛋白TN2 (TIR-NBS2)和钙依赖蛋白激酶CPK5，并且CPK5可以直接磷酸化EXO70B1。但是，CPK5磷酸化EXO70B1在囊泡运输以及TN2介导的免疫途径中发挥的作用还不清楚。本项目拟利用遗传学、细胞生物学、生物化学和分子生物学等方法深入研究CPK5在囊泡运输和植物免疫中的功能，明确CPK5是否通过磷酸化EXO70B1影响FLS2等向细胞膜运输，进而调控植物免疫，揭示EXO70B1磷酸化在TN2介导的免疫反应中的生物学意义，为植物抗病领域和植物抗性育种提供新的理论支持。

Exocyst complex functions in tethering the Golgi-derived vesicles to the plasma membrane (PM), which is a crucial step of vesicles trafficking pathway. The Arabidopsis exocyst subunit EXO70B1 positively regulates plant immunity by modulating the accumulation of FLAGELLIN SENSING 2 (FLS2) at the PM. Loss-of-function mutant exo70B1 displays spontaneous cell death and enhanced resistance to a range of pathogens. The activated immune responses in exo70B1 mutants require the atypical NLR protein TIR-NBS2 (TN2) and CALCIUM-DEPENDENT PROTEIN KINASE 5 (CPK5), and CPK5 directly phosphorylates EXO70B1. However, whether the phosphorylation of EXO70B1 by CPK5 plays a role in vesicles trafficking and the TN2-mediated immune responses is not clear. In this project, we will use the combination of genetic, cellular, biochemical and molecular approaches to study the roles of CPK5 in vesicles trafficking and plant immunity. Finally, we aim to demonstrate whether CPK5 regulates plant immunity by phosphorylating EXO70B1 and affecting the trafficking of FLS2 to the PM, and reveal the significance of EXO70B1 phosphorylation in TN2-mediated plant immunity, which can support new views for the field of plant resistance and plant resistance breeding.