JNK/p38 MAPK信号通路在二化螟对Bt毒素防御机制中的作用

苏云金芽孢杆菌（Bt）产生的Cry毒素是典型的成孔毒素，已成功并广泛地应用于害虫防治中，但有关靶标昆虫对其细胞水平上的防御机制缺乏深入研究。在模式生物抵御成孔毒素过程中，JNK和p38 MAPK信号通路发挥重要作用。MAPK信号通路在多种昆虫中存在，申请者前期研究发现JNK和p38基因也存在于二化螟中，并可经Cry1A毒素诱导后表达量上升。这是否意味着JNK和p38 MAPK信号通路参与了二化螟对Bt毒素的防御过程？本项目采用实时定量PCR和western blot等技术分析JNK和p38 MAPK信号通路在二化螟防御Cry毒素过程中的作用；通过信号通路阻断剂法、RNA干扰和TUNEL等技术，阐明关键的MAPK信号通路。研究结果将对理解Cry毒素的作用模式，提高其对靶标昆虫的毒力具有重要意义，同时为延缓靶标昆虫对转Bt抗虫作物的抗性发展，扩大转Bt抗虫作物杀虫谱提供新的思路和理论依据。

The Cry toxin made by Bacillus thuringiensis is an important pore-forming toxin (PFT) and was successfully utilized in agricultural pest management. But the cellular response of target insects to respectively specific Cry toxins was poorly understood. Both JNK and p38 mitogen-activated protein kinase (MAPK) pathways were known to be activated in model organisms in response to a variety of PFT. Through searching in our local database of the Chilo suppressalis midgut transcriptome, we found both JNK and p38 MAPK pathways existing in this organism. Further NCBI searching proved that the JNK and p38 MAPK pathways exist in a wide range of insect species. Moreover, our previous data showed that the expression level of both JNK and p38 from C. suppressalis midgut increased after Cry1Ac treatment. Based on above information, we aimed to deeply analyze the cellular response of C. suppressalis to the Cry1Ac by quantitative real-time PCR and western blot. The RNAi technique, TUNEL staining and specific MAPK pathway inhibitor will also be used to clarify roles played by the two pathways in cellular defense to Bt-toxins. Our study will doubtless improve the understanding of the action mechanism of Cry toxins. Our results would also be help in promoting toxicity on target pests, management of pest resistance and expanding target spectrum of transgenic crops.