茶树对茶饼病危害诱导的防御反应分子机制研究

Diseas has become an importance factor to limit the tea high yield, good quality and high efficiency. On the other side, the problem of pesticide residues has also become an importance factor to limit the tea export in China. Therefore, in order to ensure the safety and sustainable development of tea, it is important to study defense mechanism and dig out resistance gene of the tea plant. Aimed at the common occurring Exobasidium vexans, the present project will involve resistant and susceptible tea varieties. Digital Gene Expression (DGE) tag Profiling will be used to compare the differential transcriptome between resistant and susceptible tea varieties and study the expression difference for different experiments. And then, resistance-related gene will be screened; the full-length cDNA of those genes would be cloned and amplified; the function will be identified. Finally, the expressions law of the resistance-related gene in different elicitors under inducing will studied with quantitative RT-PCR technique. The important elicitors, which can induce expressions of the resistance related gene and increase the resistance of tea plan, will be screened. Through these works, not only can the molecular mechanisms of defense induced by the damage of tea plant Camellia diseases be fully revealed, but also can provide theoretical basis and practical application value for tea disease comprehensive prevention and treatment.

茶树病害一直是我国茶叶高产、优质和高效的重要限制因子之一；同时茶树病害及其防御过程中的农残问题也是限制我国茶叶产品出口的重要因素。因此，开展茶树抗病的防御机理、发掘抗病基因资源等相关研究，为保障茶叶安全和可持续发展具有重要的意义。本项目针对茶树发生较为普遍的茶饼病，选用抗茶饼病茶树品种和感茶饼病品种为材料，拟采用RNA-seq技术对茶饼病危害诱导前后的转录组进行测序，一是比较抗病茶树和感病茶树被茶饼病危害前后的转录组进行数字表达谱分析，研究差异表达基因的数量和种类；二是筛选出抗病相关基因并进行全长cDNA的克隆和功能鉴定；三是选用不同的激发子处理茶树，利用荧光定量PCR研究抗病基因在不同诱导子诱导下的表达规律，筛选出能诱导茶树抗病基因表达、提高茶树抗病的激发子。通过这些研究，不仅能够全面揭示茶树对茶饼病危害诱导防御的分子机制，还能为茶树茶饼病的综合防治提供理论依据和实际应用价值。

茶饼病(Exobosidium vexans Massee)又称疱状叶枯病、叶肿病，属担子菌亚门真菌，是我国茶叶高产、优质和高效的重要限制因子之一，开展茶树抗病的防御机理、发掘抗病基因资源等相关研究，为保障茶叶安全和可持续发展具有重要的意义。为揭示茶树被茶饼病危害诱导的防御反应机制，本课题选用感病茶树和抗病茶树为材料，通过RNA-seq、数字基因表达谱，并结合生物信息学等方法与技术，共筛选出差异基因974条，其中共有122条，抗病品种中特异364条，感病品种中特异488条；通过对抗病品种云茶1号叶片的全长转录组测序，获得具有完整编码的CDS 223120个，包含茶树抗茶饼病相关的基因WRKY24, NAC14, ACCO3 and PAL；对感病前后的植物激素含量变化分析发现，水杨酸（SA）和茉莉酸（JA）参与茶树抗茶饼病反应；通过田间调查、酶活性分析，筛选出水杨酸浓度为1mM、茉莉酸浓度为0.1mM对茶树茶饼病有较好的抑制作用，水杨酸和茉莉酸可以作为茶树抗茶饼病的诱导子；上述研究结果为后续基因功能验证以及茶树抗茶饼病机制奠定研究基础；通过项目实施发表科技论文5篇，项目负责人入选云南省现代茶叶产业技术体系首席科学家，成员1人晋升研究员，1人晋升助理研究员。