糖信号对茶树叶片黄酮醇苷合成积累的调节和作用机制

黄酮醇苷是茶树重要的次生代谢产物，是茶叶苦涩味物质之一。可溶性糖是植物次生代谢的基础合成原料，并通过信号通路调控植物多项生命活动。本项目拟通过检测不同茶树品种新梢生育中黄酮醇苷和可溶性糖组分及含量的变化，结合基因定量表达和关键酶活力检测从糖代谢、糖转运蛋白和糖信号通路的角度探讨糖信号调节黄酮醇苷合成积累的作用机制。采用不同外源糖诱导处理茶树离体枝条，揭示与茶树黄酮醇苷合成密切相关的关键糖组分及其糖信号转导机制，以及不同品种茶树黄酮醇苷合成途径对糖诱导的差异响应，进而通过抑制剂处理对糖信号转导的关键步骤、关键基因及酶进行功能验证。本项目从糖生物学的角度阐释糖作为信号因子对茶叶黄酮醇苷合成的调控和作用机制，研究结果有助于更深入地了解茶叶黄酮醇苷的代谢机理及茶树次生代谢调控网络，为开发相应的控制技术措施提供科学依据。

Flavonol glycosides are important secondary metabolites in tea plant, which contributes to the bitter and astringent taste of tea. Sugars are basic biomaterials for secondary metabolisms in plant, which regulate many life activities through sugar signal transduction. This project is to reveal the mechanism of sugar-mediated biosynthesis of flavonol glycosides in tea plant through determination of flavonol glycosides and soluble sugars, relevant gene expressions and enzymatic activities regarding sugar metabolism, transporting, sugar sensing and signal transduction. Branch cut-offs of tea plant are to be treated with different exogenous sugars so as to find out the most important sugar component closely related to the biosynthesis of flavonol glycosides and related sugar signaling pathway, as well as the differential responses of various tea cultivars to exogenous sugar. Inhibiter or blocker treatments are to testify the crucial step, critical gene and enzyme in relevant sugar signaling pathway. This study would give essential information to understand the regulation of flavonol glycosides biosynthesis from a viewpoint of glycobiology, and the promising results help to better understand the metabolism of flavonol glycosides and the regulatory network of tea secondary metabolism, and also provide scientific basis for future control techniques on biosynthesis of flavonol glycosides.