囊泡运输系统负责将细胞内的蛋白质等货物分子运至细胞的特定部位，因而广泛参与植物的生长发育和环境应答。然而植物中囊泡运输调控蛋白本身的翻译后修饰及其生物学功能尚缺乏深入研究。本项目拟以植物中独有的囊泡运输调控蛋白FREE1的翻译后修饰及其生理功能研究为切入点，从分子细胞及遗传等多个角度研究植物脱落酸（ABA）和盐（NaCl）胁迫信号响应中FREE1蛋白磷酸化修饰的调控、FREE1蛋白的磷酸化位点及其功能分析、FREE1蛋白亚细胞定位的变化以及细胞核内FREE1互作蛋白的分离和功能分析，重点研究FREE1蛋白磷酸化修饰的调控机制及磷酸化后行使的功能，最终阐明FREE1调控植物响应ABA和NaCl胁迫信号的分子机制。本研究将揭示植物囊泡运输调控蛋白在调控植物环境应答方面的全新功能，并将丰富植物ABA信号转导和盐胁迫响应调控网络的研究，为农作物的抗逆改良提供理论依据。

Vesicular transport system is responsible for intracellular transport of proteins and other cargoes to the specific parts of a cell, and is widely involved in the regulation of plant growth and environmental responses. However, the post-translational modifications of vesicular transport regulators and the biological functions of such modifications are still lack of in-depth study in plant. This proposal intends to study the regulation and function of post-translational modifications of FREE1, a plant unique vesicular transport regulator, in the plant response to ABA and salinity stresses. Our study includes the regulatory mechanism of FREE1 phosphorylation, FREE1 protein phosphorylation sites and functional analysis, subcellular localization change of FREE1 protein, the identification of FREE1 interaction partners and their functional studies in nucleus. We will focus on the regulatory mechanism of FREE1 phosphorylation and the functions of FREE1 after phosphorylation, and eventually we will clarify the molecular function of FREE1 in the regulation of plant responses to ABA and NaCl stress signals. This study will reveal the new function of plant vesicular transport regulators in the regulation of plant responses to environmental stimuli. In addition, this study can contribute to our knowledge of the signal transduction network of ABA and salinity stress in plants and thus provides the theoretical basis for the improvement of crop resistance to environmental stresses.