3个TIR-NB-LRR类抗橡胶树白粉病基因协同作用机理的研究

橡胶树白粉菌在拟南芥生态型Lag2-2表现抗性减弱的表型，全基因组测序发现Lag2-2 TIR-NB-LRR类抗性蛋白ROH1发生了终止突变，表型分析进一步证实ROH1参与拟南芥对橡胶树白粉菌的抗病性。通过对ROH1所在基因组上下游序列分析，发现另外两个TIR-NB-LRR类基因ROH2和ROH3与ROH1位于同一基因簇内，同时，roh2和roh3突变体也表现对橡胶树白粉菌感病性提高的表型，免疫共沉淀试验证实ROH1和ROH3发生相互作用，推测ROH1，ROH2和ROH3通过协同作用实现拟南芥对白粉菌的抗病性。本项目在此工作的基础上，进一步通过免疫共沉淀和pull down试验确定ROH1，ROH2和ROH3 3个蛋白之间是否存在两两互作及互作结构域，并从遗传学和细胞学角度深入研究3个蛋白的抗性机理和潜在的协同作用机制，为防治橡胶树白粉病奠定坚实的理论基础。

It has been reported that Arabidopsis accession Lag2-2 showed significant susceptibility to Oidium heveae (O. heveae), and recently we found there is a stop mutation of the Toll-Interleukin1 Receptor (TIR)-nucleotide binding (NB)-leucine-rich repeat (LRR) protein named ROH1（Resistance to O. heveae）in Lag2-2 by the genomic sequencing. Further study confirmed that ROH1 contributes to the disease resistance to O. heveae. Through the genome localization analysis of ROH1, another two TIR-NB-LRR-type genes ROH2 and ROH3 reside within a single locus with ROH1. Loss-of-function mutations of ROH2 and ROH3 also displayed remarkable susceptibility to O. heveae. In addition, Co-immunoprecipitation assay showed that ROH1 can interact with ROH3 in Arabidopsis protoplast, indicating that ROH1, ROH2 and ROH3 may function together in disease resistance against O. heveae. Thus, in this project, we will further determine the interactions between ROH1, ROH2 and ROH3 by Co-immunoprecipitation and pull down assays and confirm the interaction domains of these three proteins. Also, the co-function mechanisms employed by ROH1,ROH2 and ROH3 in resistance against O. heveae will be explored through genetics, cytology methods. Overall, this study will provide a basis for future prevention of powdery mildew caused by O. heveae in rubber trees.