草地贪夜蛾与斜纹夜蛾解毒相关基因的比较分析

草地贪夜蛾Spodoptera frugiperda近期在中国为害猖獗,由于繁殖速度快,迁飞能力强,在本土呈现爆发趋势,严重为害了我国农作物。与本地近缘物种斜纹夜蛾Spodoptera litura相比,草地贪夜蛾更偏好玉米、水稻、小麦等禾本科农作物,且对多种化学杀虫剂及转基因Bt玉米产生抗性。寄主适应性以及杀虫剂抗性与解毒代谢相关蛋白密切相关。因此,本研究对这两种夜蛾科害虫的解毒代谢相关蛋白——细胞色素P450、谷胱甘肽转移酶(GST)及ABC转运蛋白进行了全基因组水平系统的搜集和数目比较,构建系统发育树并对P450和GST部分基因扩张分支进行氨基酸差异位点分析。结果显示,在草地贪夜蛾中共鉴定出213个P450基因、58个GST基因、102个ABC基因,其中P450基因与GST基因数目远远多于斜纹夜蛾(116,37),而ABC基因数目与斜纹夜蛾(99)接近。系统发育树分析表明,草地贪夜蛾P450在CYP6、CYP9以及CYP4功能簇,GST在部分进化分支上都发生了显著基因扩张,发生显著扩张的基因中有数个氨基酸突变,其中一些突变被预测可能影响蛋白质功能。但出乎意料的是,ABC亚家族B和E在斜纹夜蛾聚集成簇并发生了显著的基因扩张现象。以上结果暗示入侵种草地贪夜蛾和本地近缘物种斜纹夜蛾在抗性方面可能发展出各自独特的应对机制。本研究为解析草地贪夜蛾解毒抗性特征机制提供基因数据,为草地贪夜蛾的生物防治及抗性研究提供参考依据。

Comparative analysis of detoxification related genes in Spodoptera frugiperda and Spodoptera litura

Spodoptera frugiperda invaded in China recently. Due to its fast reproduction speed and strong migration ability, its populations expand rapidly in China, causing severe damage to the crops. Compared with its related species S. litura which is native in China, the S. frugiperda prefers to feed corn, rice, wheat and other gramineous crops, and has developed resistance to a variety of chemical pesticides and transgenic Bt corn. Host adaptability and insecticide resistance are closely related to proteins involved in detoxification metabolism. Hence, in this study, the detoxification metabolism related proteins, including cytochrome P450, glutathione S. transferase (GST), ABC transporter, were systematically searched in the genomes of the two relative pests, and the numbers of them were compared. Furthermore, the phylogenetic trees were constructed for genome wide evolutionary analysis, based on which amino acid sequences of of those cytochrome P450 and GST gene members in the clades with expansion were analyzed. Totally, 213 cytochrome P450, 58 GST and 102 ABC transporters were identified in S. frugiperda. The number of P 450 s and GSTs was far more than those of S. litura (116, 37) , while the number of ABC transporters was close to that of S. litura (99). Phylogenetic analyses showed that S. frugiperda P450s in CYP6, CYP9 and CYP4 clusters and GSTs in certain branches showed obvious expansion Among these members, we also identified several amino acid mutations, some of which were predicated to affect protein function. On the contrary, we observed that B and E family of the S. litura ABC transporters clustered in and demonstrated obvious expansion in S. litura. These finding suggest that the invasive S. frugiperda and its native relative S. litura may evolved their own unique resistance mechanisms. This study provides not only genetic data resource for the analysis of the detoxification resistance mechanism of S. frugiperda, but also reference for the biological control and resistance research of Spodoptera pests.