MAPK信号途径调控小菜蛾对Bt杀虫蛋白抗性的遗传网络解析

Insufficient understanding of the toxicology and resistance mechanisms of Bacillus thuringiensis (Bt)-based microbial insecticide seriously restricts its resistance management and the further exploitation and application of its novel insecticidal proteins, moreover, it also seriously threatens the future sustainable utilization of Bt transgenic crops. Our previous study showed that the mitogen-activated protein kinase (MAPK) signaling pathway can trans-regulate Bt receptor genes including alkaline phosphatase (ALP) and ATP-binding cassette (ABC) transporter genes, which finally results in the Bt resistance in diamondback moth, Plutella xylostella (L.). Then, on this basis, the current foundation aims to further clarify the structure of MAPK signaling pathway and cloning the corresponding genes in Bt-susceptible and -resistant P. xylostella by utilizing the whole-genome sequence information of P. xylostella and sereral bioinformatics tools. And it also aims to study and illuminate the mode of signal transmission and feature of hierarchical regulation among genes in the MAPK signnaling MAP4K-MAP3K-MAP2K-MAPK cascade gene family and its terminal p38, JNK and ERK kinase branches. Addtionally, we will further screen the terminal transcription factors (TFs) controlled by the MAPK patheway to pinpoint the interplay between these TFs and their regulated Bt receptor genes. Finally, we will illustrate the mode of hierarchical regulation of Bt receptor genes in the MAPK singnaling pathway, which will reveal the molecular toxicology mechanisms of Bt biopesticide to P. xylostella and the molecular resistance mechanisms and its genetic regulation networks of P. xylostella to Bt biopesticide. The results of this study are of great theoretical and practical significance for further exploitation and application of novel Bt insecticidal proteins.

对微生物杀虫剂Bt毒理与抗性机制的认识不足，正严重制约着Bt抗药性治理和新型Bt杀虫蛋白的开发与应用，并威胁着转Bt基因作物的使用。. 申请者前期研究发现，MAPK信号途径反式调控Bt受体基因碱性磷酸酶和ABC转运蛋白导致了小菜蛾对Bt的抗药性。本项目拟在此基础上，利用小菜蛾全基因组序列和生物信息学手段进一步解析敏感与抗性小菜蛾MAPK信号通路结构并克隆相关基因；研究阐明通路中MAP4K-MAP3K-MAP2K-MAPK信号级联基因家族与末端p38、JNK和ERK激酶支路各基因间的信号传递模式与层级调控特性；筛选MAPK通路末端调控的转录因子，明确转录因子与调控的Bt受体基因间的互作特性；最终阐明MAPK信号途径对Bt受体的层级调控模式，揭示Bt的分子毒理机制与小菜蛾对Bt抗性的分子机理。研究结果对Bt杀虫蛋白的开发与可持续应用具有重要的理论和实践意义。

对微生物杀虫剂Bt毒理与抗性机制的认识不足，正严重制约着Bt抗药性治理和新型Bt杀虫蛋白的开发与应用，并威胁着转Bt基因作物的使用。申请者前期研究发现，激活的MAPK信号途径反式调控中肠基因ALP和ABCC1-3导致小菜蛾对Bt Cry1Ac杀虫蛋白的抗药性，然而，MAPK信号途径上游激活信号、中游信号级联路径和下游响应转录因子和靶标中肠基因尚不清楚。因此，本项目利用生物信息学、生物化学、分子生物学和遗传学等技术手段，进一步发现了昆虫激素含量升高及其串扰是激活MAPK信号途径的上游关键信号，阐明了Bt抗性小菜蛾中MAPK信号途径中间四级信号级联路径的信号传递模式与层级调控特性，揭示了MAPK信号途径反式调控的下游响应转录因子和靶标中肠基因，最终全面解析了MAPK信号途径介导的小菜蛾Bt Cry1Ac杀虫蛋白抗性新机制。研究结果对Bt杀虫蛋白的开发与可持续应用具有重要的理论和实践意义。