Cry1Ca诱导的二化螟p38 MAPK下游转录因子的鉴定及功能分析

Insect cellular defense against Cry toxin is mainly regulated by MAPK pathways, but the MAPK pathway does not act as direct defense genes. Our previous study found that p38 MAPK is involved in the defense process of Chilo suppressalis against Cry1Ca, but the downstream functional genes responses to Cry1Ca stress are still unknown. The major substrate of p38 MAPK is transcription factor, identification of specific transcription factor is the first step of functional genes. This project would clearly identify specific downstream transcription factor of p38 MAPK that response to Cry1Ca infection by techniques of RNAi, eukaryotic expression and protein phosphorylation. These results would definitely improve the understanding of the insect defense mechanism against Cry toins, and would also benefit improving Cry toxin toxicity and delaying resistance development of target insects.

昆虫对Cry蛋白的细胞防御反应主要受MAPK路径调控，而MAPK 只是应急信号通路之一，并不直接参与对抗成孔毒素，其下游基因才起真正的防御作用。申请人前期研究发现，p38 MAPK参与了二化螟对Cry1Ca的防御过程，但对Cry1Ca起防御作用的二化螟p38 MAPK下游基因并不清楚。p38 MAPK下游底物主要为转录因子，鉴定转录因子是寻找下游功能基因的前提。因此，本项目将采用RNA干扰、真核表达和蛋白磷酸化活性检测等技术鉴定受Cry1Ca诱导的p38 MAPK下游转录因子，进而确定与二化螟对Cry1Ca敏感性连锁的主效转录因子。研究结果对明确昆虫对Cry蛋白的防御机制具有重要意义，同时为提高Cry蛋白对靶标昆虫的毒力、延缓靶标昆虫对转Bt抗虫作物的抗性发展提供新的思路和理论依据。

昆虫对Cry蛋白的细胞防御反应主要受MAPK路径调控，而MAPK 只是应急信号通路之一，并不直接参与对抗成孔毒素，其下游基因才起真正的防御作用。本项目组前期研究发现，p38 MAPK参与了二化螟对Cry1Ca的防御过程，本项目则是在此基础上，采用差异转录组测序、差异磷酸化蛋白组测序和RNA干扰等技术鉴定受Cry1Ca诱导的p38 MAPK下游转录因子，结果发现，gene568、gene967、gene1585、gene2921、gene101和gene12590参与了二化螟对Cry1Ca的防御过程；而genef2则参与了Cry1Ca对二化螟的作用过程，此外，p38是gene568、gene967、genef2和gene2921的上游调控基因，其调控机制并非直接磷酸化激活，有待进一步验证。本研究所取得的结果对明确昆虫对Cry蛋白的防御机制具有重要意义，同时为提高Cry蛋白对靶标昆虫的毒力、延缓靶标昆虫对转Bt抗虫作物的抗性发展提供新的思路和理论依据。