小菜蛾CYP6BG1基因体外真核表达及其对氯虫苯甲酰胺的代谢

小菜蛾Plutella xylostella是为害十字花科作物的世界性重要害虫,对氯虫苯甲酰胺产生了严重抗性。已经明确小菜蛾CYP6BG1的过量表达与其对氯虫苯甲酰胺的抗性相关。本文进一步通过昆虫杆状病毒表达系统在Sf9细胞中表达了小菜蛾CYP6BG1和NADPH-细胞色素P450还原酶(CPR)蛋白,并检测Sf9细胞表达CYP6BG1蛋白后对氯虫苯甲酰胺的敏感变化及氯虫苯甲酰胺经CYP6BG1蛋白代谢后对小菜蛾幼虫毒力的变化。结果显示:Sf9细胞中与CPR共表达的CYP6BG1具有7-乙氧基香豆素O-脱乙基酶活性,且细胞对氯虫苯甲酰胺的敏感性显著下降。将表达的蛋白与不同浓度的氯虫苯甲酰胺孵育24 h后,对3龄小菜蛾幼虫致死率显著低于对照组。本研究结果间接表明CYP6BG1能够降解氯虫苯甲酰胺,从而增强小菜蛾对氯虫苯甲酰胺的抗性。

Eukaryotic expression of Plutella xylostella CYP6BG1 in vitro and its metabolism ability to chlorantraniliprole

Plutella xylostella is an important pest of cruciferous crops worldwide and has developed severe resistance to chlorantraniliprole. The overexpression of CYP6BG1 has been proved to be involved in chlorantraniliprole resistance in P. xylostella previously. In this study, the CYP6BG1 protein and NADPH cytochrome P450 reductase (CPR) protein were co-expressed in Sf9 cell lines using the Bac-to-Bac baculovirus expression system. In addition, the toxicity of chlorantraniliprole to Sf9 cells expressing CYP6BG1 and CPR proteins was determined. The sensitivity of P. xylostella larvae to chlorantraniliprole was also tested after chlorantraniliprole was incubated with expressed CYP6BG1 and CPR proteins for 24 h. The results showed that the expressed CYP6BG1 had the O-deethylation activity to 7-ethoxycoumarin, and the toxicity of chlorantraniliprole to the Sf9 cells expressing CYP6BG1 and CPR was reduced. Moreover, the incubation with expressed CYP6BG1 protein reduced the toxicity of chlorantraniliprole to third-instar larvae of P. xylostella. These results provide further evidence that CYP6BG1 plays a role in the resistance of P. xylostella to chlorantraniliprole.