叶片的衰老影响作物生长、营养积累和产量的形成。植物多肽作为信号分子参与调控多个生长发育过程，其中IDA多肽作为调控器官脱落的关键因子获得了广泛的关注，但是，目前尚无IDA多肽信号途径参与调控叶片衰老的报道。申请人前期发现IDA多肽是拟南芥叶片衰老的正调控因子，证明了其对衰老的调控依赖于受体激酶HAE和HSL2，然而IDA如何激活受体HAE/HSL2以及通过控制哪些下游因子调控叶片衰老进程尚不明确，有待深入研究。本项目拟在前期工作基础上深入解析HAE/HSL2基因的功能及作用机制：分析HAE/HSL2的衰老表达特征；明确其在叶片衰老过程中磷酸化变化的规律并鉴定信号传递的关键位点；鉴定HAE/HSL2胞内信号传递途径及下游衰老调控因子。本项目将揭示HAE/HSL2受体激活的分子机制，阐明IDA信号途径参与调控叶片衰老的分子机理，为深入研究衰老调控网络奠定基础。

Leaf senescence has a great impact on growth, nutrient accumulation and yield of crop plants. Plant peptide signals play regulatory roles in a number of plant developmental processes. Among them, the IDA peptide has been well studied as a key regulator of organ abscission. But whether it is involved in the regulation of leaf senescence has not been reported. Previous studies by this applicant has identified IDA as a positive regulator of leaf senescence in Arabidopsis, and its senescence regulating function is dependent on the receptor kinases HAESA (HAE) and HAESA-LIKE2 (HSL2). In order to find out how HAE/HSL2 receptors are activated by IDA and what downstream factors are involved in the regulation of leaf senescence, in this proposed research we will study the function and mechanisms of HAE/HSL2 in depth: analyze HAE/HSL2 expression characteristics during leaf senescence; investigate the changes in phosphorylation status of HAE/HSL2 receptors during leaf senescence and identify key residues in signal transmission; identify the subsequent intracellular signaling pathway and downstream senescence regulators of HAE/HSL2 proteins. Results from this study will for the first time elucidate the activation mechanisms of the HAE/HSL2 receptors and the mechanisms of leaf senescence regulation by the IDA signaling pathway, which will facilitate in depth understanding of the molecular regulatory network of leaf senescence.