SPY和SEC是拟南芥中两个可能的O-连接糖基化转移酶，有报道称SPY蛋白参与干旱响应，但其分子机理及脱落酸（ABA）是否参与尚不清楚。本课题通过遗传学方法探讨SPY蛋白如何参与ABA和干旱信号转导通路，揭示SPY与ABA信号通路关键蛋白之间的关系。前期工作筛选到SPY互作蛋白—辅分子伴侣蛋白CPN20，拟用多种方法验证这种互作的真实性；通过SPY（SEC）与CPN20相互作用的表型分析和遗传分析，分析它们的遗传和功能关系；研究SPY（SEC）与CPN20的定位及其与ABA的关系；用哺乳动物（和大肠杆菌）细胞体系检测CPN20的O-连接糖基化及其对SPY（SEC）的依赖性；进而检测植物体内CPN20的O-连接糖基化及其对SPY和SEC的可能依赖性。目的在于揭示SPY蛋白参与ABA和干旱信号转导途径的分子基础，弄清楚SPY与CPN20相互作用的生物学功能及其生化和细胞学基础。

SPINDLY (SPY) and SECRET AGENT (SEC) are two putative O-linked N-acetylglucosamine transferases (OGTs) in Arabidopsis. It has been previously reported that the mutation of both SPY and SEC causes embryo lethality, indicating that they play a crucial role in embro development. While spy mutant plants have defects in response to gibberllin and cytokinin, SPY is also involved in light, meristem activity, root growth, circadian rhythms, and response to drought stress. In addition, it remains unclear whether abscisic acid (ABA) is involved in SPY regulation of drought response. If SPY is involved in ABA signaling, it is also elusive what role SPY may play and how SPY is related to the established major ABA signaling pathways. This project would employ two strategies to address above questions. We investigate how SPY is involved in ABA and drought signaling to uncover the relationship between SPY and the key proteins of major ABA signaling pathways. Another strategy is to screen for SPY-interacting proteins by using yeast-two hybrid assay. In the previous attempt, we have successfully screened a SPY-interacting protein, CPN20, a co-chaperone protein that locates in stroma of chloroplasts. We will make use of multiple approaches including pull-down, co-immunoprecipitation, BiFC and split-LUC assays to confirm the interaction between SPY (SEC) and CPN20. We also make genetic and phenotypical analyses to address the genetic and functional relationship between SPY (SEC) and CPN20. We explore the cellular localization of SPY (SEC) and CPN20 and its relationship with ABA. We detect the possible O-GlcNAc modification of CPN20 and its dependence on SPY (SEC) in mammalian and bacteria cells, and eventually in plants. We aim to elucidate the molecular basis for the involvement of SPY in ABA and drought signaling, and to reveal the biological function of SPY-CPN20 interaction and its biochemical and cytological basis.