热胁迫已经成为影响农作物生产的重要环境因子之一，然而目前植物耐热性形成的分子机制尚未完全阐明。我们前期发现，细胞壁关联的类受体蛋白激酶基因CaWAKL20通过抑制ABA信号而负调控辣椒耐热性。在此基础上，本项目拟首先分析细胞膜流动性改变和膜外结构域更换对CaWAKL20基因表达的影响，进一步明确其耐热调控功能，同时对ABA信号途径中与CaWAKL20有预测互作或共表达关系的蛋白成员进行点对点验证。然后以CaWAKL20基因的辣椒沉默表达植株、辣椒或番茄过表达株系为试材，分析热胁迫下ABA合成、代谢、转运以及信号转导基因表达和ABA响应蛋白降解情况。最后，将ABA信号途径中与CaWAKL20互作或受CaWAKL20调控的目标基因进行沉默表达和过表达，验证其耐热功能。通过本项目实施，有望初步明确CaWAKL20基因介导ABA信号调控辣椒耐热性的分子机制，为全面阐明植物耐热性形成的机制提供依据。

Heat stress has become one of the most important environmental factors adversely affecting crops production; however, so far, the molecular mechanisms of plant thermotolerance development are incompletely understood. In previous research work, we found wall-associated receptor-like kinase gene CaWAKL20 negatively regulates pepper thermotolerance by repressing ABA signaling. This project will further explore the contributions of CaWAKL20 to pepper thermotolerance regulation, by analyzing the effects of fluidity modifier of cell membrane and changing of extracellular domain on CaWAKL20 expression. At the same time, the interactions between CaWAKL20 and its predicted partners in ABA signaling pathway were confirmed point-to-point by yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. And then, taking the pepper plants with CaWAKL20 silencing and pepper or tomato lines with CaWAKL20 overexpression as materials, the heat responses of gene expression of ABA synthesis, metabolism, transport and signaling transduction, and degradation of ABA response proteins were investigated. At last, the thermotolerance-related functions of CaWAKL20 interacting partner genes and ABA signaling genes regulated by CaWAKL20 were validated by the techniques of gene silencing and overexpression. By this project, the molecular mechanisms of CaWAKL20 regulating pepper thermotolerance through mediating ABA signaling will be primarily clarified, which will then provide experimental proofs for fully understanding the molecular mechanisms of plant thermotolerance development.