College of Resources and Environment, Henan Institute of Science and Technology, Xinxiang, Henan Province, P.R. China.
Department of Entomology, China Agricultural University, Beijing, P.R. China.
J Insect Sci. 2020 May 1;20(3). doi: 10.1093/jisesa/ieaa047.
Fall armyworm, Spodoptera frugiperda (Smith), has caused significant losses for crop production in China. The fall armyworm is mainly controlled by the chemical insecticides, whereas the frequent application of insecticides would result in the resistance development. Insect cytochrome P450 monooxygenases play an essential part in the detoxification of insecticides. In this study, five P450 genes were selected to determine the role in response to insecticides by RNA interference (RNAi). Developmental expression pattern analysis revealed that S. frugiperda CYP321A8, CYP321A9, and CYP321B1 were highest in second-instar larvae among developmental stages, with 2.04-, 3.39-, and 8.58-fold compared with eggs, whereas CYP337B5 and CYP6AE44 were highest in adult stage, with 16.3- and 10.6-fold in comparison of eggs, respectively. Tissue-specific expression pattern analysis exhibited that CYP321A8, CYP321B1, and CYP6AE44 were highest in the midguts, with 3.56-, 3.33-, and 3.04-fold compared with heads, whereas CYP321A9 and CYP337B5 were highest in wings, with 3.07- and 3.36-fold compared with heads, respectively. RNAi was also conducted to explore detoxification effects of the five P450 genes on chlorantraniliprole. The second-instar larvae became more sensitive to chlorantraniliprole with a higher mortality rate than the control, after silencing CYP321A8, CYP321A9, and CYP321B1, respectively. These findings strongly supported our viewpoint that CYP321A8, CYP321A9, and CYP321B1 may play a critical role in insecticide detoxification. It will provide a basis for further study on regulation of P450 genes and the management of S. frugiperda.
草地贪夜蛾，也称秋黏虫，（Spodoptera frugiperda (Smith)），对中国的农作物生产造成了重大损失。草地贪夜蛾主要通过化学杀虫剂进行控制，然而频繁使用杀虫剂会导致抗药性的产生。昆虫细胞色素 P450 单加氧酶在杀虫剂解毒中起着至关重要的作用。在这项研究中，选择了五个 P450 基因通过 RNA 干扰（RNAi）来确定其对杀虫剂的反应作用。发育表达模式分析表明，S. frugiperda CYP321A8、CYP321A9 和 CYP321B1 在发育阶段的二龄幼虫中表达量最高，与卵相比分别为 2.04、3.39 和 8.58 倍，而 CYP337B5 和 CYP6AE44 在成虫阶段表达量最高，与卵相比分别为 16.3 和 10.6 倍。组织特异性表达模式分析表明，CYP321A8、CYP321B1 和 CYP6AE44 在中肠中表达量最高，与头部相比分别为 3.56、3.33 和 3.04 倍，而 CYP321A9 和 CYP337B5 在翅膀中表达量最高，与头部相比分别为 3.07 和 3.36 倍。还进行了 RNAi 以探索这五个 P450 基因对氯虫苯甲酰胺的解毒作用。沉默 CYP321A8、CYP321A9 和 CYP321B1 后，二龄幼虫对氯虫苯甲酰胺的敏感性比对照更高，死亡率也更高。这些发现有力地支持了我们的观点，即 CYP321A8、CYP321A9 和 CYP321B1 可能在杀虫剂解毒中起关键作用。这将为进一步研究 P450 基因的调控和草地贪夜蛾的管理提供依据。
