基于组学的茶树抗轮斑病的防御机制研究

Tea grey blight is one of the main diseases of tea tree, which greatly restricts the improvement of tea quality and efficiency. However, there is still no systematic study on the defensive mechanism of Camellia Sinensis against Pestalotiopsis theae. In the previous study, several newly discovered wild tea plants with similar sources showed significant resistance differences to the disease have been confirmed recently in the lab. Using these wild tea germ plasm resources as materials, we will try to discover the induced compounds and genes response to Pestalotiopsis theae by combined analysis of transcriptome and metabolome and hormone changes by LC-MS/MS. The function of the candidate genes will be further verified through their dynamic expression and biochemical analysis of related compounds by Transient over-expression、qRT-PCR、GC-MS 、HPLC and LC-MS/MS. The project aims to clarify the defense mechanism of Camellia sinensis and provides theoretical support for the biocontrol of tea grey blight and the breeding of disease-resistant tea tree germplasm resources.

茶轮斑病是茶树主要病害之一，对茶产业的提质增效形成了极大制约。然而茶树对轮斑病菌侵染诱导防御的机理尚不明晰。目前，本项目组在野外调研中，筛选获得对茶轮斑病抗病和易感野生茶树单株若干。据此，本项目拟以上述茶树单株为材料，探究茶树对轮斑病侵染诱导防御的机制，借助转录组测序、代谢组测序、GC-MS、HPLC及LC-MS/MS等技术，筛选出茶树抵御轮斑病侵染的目标基因和代谢物及激素；进一步通过瞬时表达和生化分析验证目标基因和代谢物及激素对茶轮斑病侵袭的抵御功能。本项目旨在明确茶树抵御茶轮斑病侵染的防御机制，研究结果将为抗病茶树种质资源的选育和病害生物防治提供重要的参考依据。

茶轮斑病作为茶树主要病害之一，已成为制约茶产业健康持续发展的重要因素，挖掘具显著抗病特性的茶树资源成为重要解决途径。目前，茶树抵御茶轮斑病侵染的相关防御机制尚不清楚。本研究挖掘了对茶轮斑病具显著抗病优势的野生茶树单株“K2”，结合对应的易感病野生茶树单株资源“K4”，综合组学分析等多种技术手段，发现抗病茶树“K2”在赖氨酸降解代谢、苯丙烷、哌啶和吡啶生物碱生物合代谢等初次生代谢具明显优势。而面对茶轮斑病侵染，“K2”抗病优势不仅在上述初生代谢路径发挥作用，其次生代谢也会提前发挥积极响应，如黄酮类代谢路径。通过特征代谢物抑制实验发现，二氢杨梅素和杨梅素对茶轮斑病具显著的抑制效果。在激素水平上，水杨酸和茉莉酸可积极应对茶轮斑病的侵染。在转录水平上，抗病茶树资源的光合作用、植物激素信号转导、氮代谢和糖酵解/糖异生等代谢对茶轮斑病侵染可发挥积极响应。另外，茶树资源“K2”也可提前激活苯丙烷、植物激素代谢以及植物与病原菌互作代谢路径中与抗病相关的基因。同时，也挖掘了3个显著响应茶轮斑病的转录因子CsRAV4、CsRAV5和CsRAV6，三者均参与了茶树抵御茶轮斑病菌侵染的应答，结合前期叶片表型感病分析结果，CsRAV4、CsRAV5和CsRAV6为茶树抵御茶轮斑病的正向调控转录因子。