Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
Int J Biol Macromol. 2022 Oct 31;219:452-462. doi: 10.1016/j.ijbiomac.2022.08.014. Epub 2022 Aug 5.
The common cutworm, Spodoptera litura, has developed with varying degrees of resistance to most commonly used insecticides. Cytochrome P450 monooxygenases (P450s) with broad substrate specificities have been frequently reported to be involved in insecticide detoxification, but the underlying mechanisms remain obscure. Herein, seven CYP6AE subfamily P450s which possess six classical substrate recognition sites and several conserved catalytic motifs were identified from the genome of S. litura. Spatiotemporal expression profiles showed that these CYP6AE subfamily members were predominantly expressed in the larval midgut. Among them, CYP6AE43 and CYP6AE48 were significantly induced by three pyrethroids including β-cypermethrin, λ-cyhalothrin and fenvalerate. Knockdown of CYP6AE43 or CYP6AE48 by RNA interference dramatically increased the larval susceptibility to the pyrethroids. When silencing them simultaneously, the larval susceptibility to pyrethroids was higher than when silencing them individually, indicating a cooperative relationship between these two P450s in pyrethroid detoxification. Homology modeling and molecular docking analyses showed that these three pyrethroids could stably bind to CYP6AE43 and CYP6AE48, with the binding free energies from -37.58 to -84.24 kcal mol. These results indicate that induction of CYP6AE43 and CYP6AE48 contributes to pyrethroid detoxification and promotes the development of resistance to pyrethroids in S. litura.
小菜蛾已对大多数常用杀虫剂产生了不同程度的抗性，其体内细胞色素 P450 单加氧酶（P450s）具有广泛的底物特异性，常被报道参与杀虫剂解毒，但潜在机制尚不清楚。本研究从小菜蛾基因组中鉴定出了 7 种 CYP6AE 亚家族 P450s，它们具有 6 个经典的底物识别位点和几个保守的催化基序。时空表达谱显示，这些 CYP6AE 亚家族成员主要在幼虫中肠表达。其中，CYP6AE43 和 CYP6AE48 被 3 种拟除虫菊酯（包括β-氯氰菊酯、氯氟氰菊酯和氰戊菊酯）显著诱导。通过 RNA 干扰敲低 CYP6AE43 或 CYP6AE48 可显著提高幼虫对拟除虫菊酯的敏感性。当同时沉默它们时，幼虫对拟除虫菊酯的敏感性高于单独沉默时，表明这两种 P450s 在拟除虫菊酯解毒中存在协同关系。同源建模和分子对接分析表明，这 3 种拟除虫菊酯均可稳定结合 CYP6AE43 和 CYP6AE48，结合自由能为-37.58 至-84.24 kcal/mol。这些结果表明，CYP6AE43 和 CYP6AE48 的诱导有助于拟除虫菊酯解毒，并促进小菜蛾对拟除虫菊酯的抗性发展。
