红豆杉中TGA因子介导的水杨酸（SA）信号转导通路调控紫杉醇合成的机制研究

紫杉醇是目前治疗癌症最有效的天然药物之一，但含量稀少。水杨酸（SA）处理能大幅提高红豆杉中紫杉醇的含量，但调控机理未知。申请人发现，多个紫杉醇合成酶基因启动子上富含TGA因子特异结合元件，推测TGA是参与SA信号转导，并调控紫杉醇合成的关键调控子。而且，红豆杉中TGA及NPR与已知同源蛋白具有不同的进化历程，推测红豆杉型SA信号转导通路与已知通路有一定差别。因此，本项目拟以紫杉醇合成调控为对象，筛选能调控紫杉醇合成的TGA因子；再筛选与之互作的NPR蛋白，检测其转导SA的能力及机制；然后，分析SA处理，对TGA-NPR蛋白复合体结构稳定性和转录调控活性的影响，比较红豆杉中SA信号转导机制与已知模式的异同。最终，明晰TGA因子介导的红豆杉型SA信号转导通路调控紫杉醇合成的机制。本项目对阐明SA信号转导通路的进化历程具有重要的理论价值；也对基因工程构建紫杉醇高产红豆杉株系具有指导意义。

Taxol, generic name Paclitaxel, is one of the most effective natural medicines for cancer treatment. Scarce content of taxol in plants result in a tight market supply. Salicylic acid is an effective stimuli factor in increasing taxol content, while the regulatory mechanism is still unclear. Previously, we found that multiple promoters of taxol synthesis genes contains specific binding elements of TGA factors. Therefore, TGA factors play key role in responding, transducing SA signals and then regulating taxol synthesis. Moreover, Taxus TGA and NPR proteins evolved differently than known ones, suggesting it has a different SA signaling transduction pathway in Taxus. To clarify the differences and regulation mechanism, we would screen functional TcTGA factors that take part in regulating taxol synthesis. Then, Taxus NPRs proteins, which transduced SA signals together with TcTGA factors, were screened and certificated in model plants. Furthermore, interaction between TcTGAs and TcNPRs would be tested, also the regulatory activities of TGA-NPR protein complex would be verified under SA treatment. Above all, SA signal transduction pathways mediated by the TGA-NPRs protein complex were clarified in Taxus, as well as the regulation mechanism of taxol biosynthesis. This study has important guiding significance for the use of Taxus cells for taxol production. Other more, SA signal transduction pathway in Taxus would improve the evolutionary understanding of plant hormone signals, since the ancient gymnosperm Taxus spp. has diversity molecular structures and occupies a specific evolution branch.