氯虫苯甲酰胺诱导甜菜夜蛾细胞色素P450基因上调表达

【目的】明确氯虫苯甲酰胺对甜菜夜蛾Spodoptera exigua (Hübner)细胞色素P450基因的诱导表达作用。【方法】采用O-脱乙基香豆素法研究了低剂量氯虫苯甲酰胺处理对甜菜夜蛾幼虫中肠P450s酶活性的影响，应用Real-time PCR方法测定了其对P450基因(CYP9A9, CYP4G37,CYP4S11和CYP6B)和NADPH细胞色素P450还原酶基因(HQ852049)表达的影响。【结果】氯虫苯甲酰胺对甜菜夜蛾P450酶及相关基因的诱导作用均表现出时间效应和剂量效应,。甜菜夜蛾4龄幼虫取食0.02 mg/kg氯虫苯甲酰胺饲料至5龄, 在蜕皮后6-36 h内, 其P450s酶活性增加为对照组的1.90~2.92倍, 诱导效应高于0.01 mg/kg氯虫苯甲酰胺处理组（其P450s酶活性为对照组的1.11~1.62倍）。同时, 0.02 mg/kg氯虫苯甲酰胺处理组甜菜夜蛾中肠P450基因CYP9A9, CYP4G37和CYP6B mRNA的相对表达量分别上升为对照组的1.97~3.95, 2.46~4.29及1.53~4.48倍, NADPH细胞色素P450还原酶基因 HQ852049 的相对表达量亦增加为对照的1.85~4.08倍。【结论】结果提示，氯虫苯甲酰胺可能通过诱导3种P450基因及细胞色素P450还原酶基因 HQ852049 基因mRNA的上调表达而增强了甜菜夜蛾幼虫中肠P450s酶活性。

Chlorantraniliprole induces up-regulated expression of cytochrome P450 genes in Spodoptera exigua (Lepidoptera: Noctuidae)

【Aim】 This study aims to understand the induction of chlorantranilprole, a novel diamide insecticide, on the expression of cytochrome P450 genes in the midgut of Spodoptera exigua (Hübner) larvae. 【Methods】 The 4th instar larvae of S. exigua were fed on artificial diets containing 0.01 and 0.02 mg/kg of chlorantraniliprole, respectively, until their molting, and the activities of O-deethylase of P450 and the mRNA expression levels of four P450 genes (CYP9A9, CYP4G37,CYP4S11 and CYP6B) and one NADPH cytochrome P450 reductase gene (HQ852049) in the midgut of the 5th instar larvae in 6 to 36 h post treatment were detected by assaying O-deethylation of ethoxyresorufin and quantitative real-time PCR, respectively. 【Results】 The cytochrome P450 ethoxycoumarin-O-deethylase activity in the 0.02 mg/kg treatment group increased to 1.90－2.92-fold as high as the untreated control, while that in 0.01 mg/kg treatment group was only 1.11－1.62 fold as high as that of the control. The relative expression levels of CYP9A9, CYP4G37and CYP6B  induced by 0.02 mg/kg chlorantraniliprole were 1.97-3.95, 2.46-4.29 and 1.53-4.48-fold as high as the control, respectively, and 0.02 mg/kg chlorantraniliprole also induced the expression of HQ852049, with the relative expression level of 1.85-4.08-fold as high as the control. 【Conclusion】 The results suggest that the up-regulated expression of three P450 genes and NADPH cytochrome P450 reductase gene  HQ852049 induced by chlorantraniliprole can enhance the activities of P450s in the midgut of S. exigua larvae.