The beet armyworm (Spodoptera exigua) is a highly polyphagous agricultural pest that is distributed worldwide. However, the adaptive mechanisms of S. exigua for various insecticides and defensive substances in host plants are unknown. Insect P450 monooxygenases play an important role in the detoxification of plant toxins and insecticides, leading to insecticides resistance. We investigated the induced effects of xanthotoxin exposure on detoxification enzyme activity and larval tolerance to α-cypermethrin in S. exigua. Our results showed that the lethal concentration (LC50) of α-cypermethrin for xanthotoxin-exposed larvae was 2.1-fold higher than in the control. Moreover, cytochrome P450 enzyme activity was significantly elevated by upregulation of P450 genes in treated larvae. RT-qPCR results showed that CYP9A10 expression level was significantly increased in all treatments, while maximal expression level was observed in xanthotoxin+α-cypermethrin-fed larvae. RNAi-mediated silencing of CYP9A10 further increased mortality by 18%, 26% and 35% at 48 h and by 27%, 43% and 55% at 72 h when larvae were exposed to diets containing chemicals as compared to the control. The results show that CYP9A10 might play an important role in xanthotoxin and α-cypermethrin detoxification in S. exigua. RNAi-mediated silencing could provide an effective synergistic agent for pest control or insecticide resistance management.

中文翻译：

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RNA 干扰介导的细胞色素 P450 基因敲低增强了 α-氯氰菊酯对甜菜夜蛾 (Hübner) 黄毒素喂养的幼虫的毒性

甜菜夜蛾（Spodoptera exigua）是一种高度多食性的农业害虫，分布于世界各地。然而，甜菜对宿主植物中各种杀虫剂和防御物质的适应机制尚不清楚。昆虫 P450 单加氧酶在植物毒素和杀虫剂的解毒中起重要作用，导致杀虫剂抗性。我们研究了黄花素暴露对甜菜中解毒酶活性和幼虫对 α-氯氰菊酯的耐受性的诱导影响。我们的结果表明，α-氯氰菊酯对暴露于黄毒毒素的幼虫的致死浓度 (LC50) 比对照高 2.1 倍。此外，通过上调处理过的幼虫中的 P450 基因，细胞色素 P450 酶活性显着提高。RT-qPCR结果表明，CYP9A10的表达水平在所有处理中均显着增加，而在黄毒毒素+α-氯氰菊酯喂养的幼虫中观察到最大表达水平。与对照相比，当幼虫暴露于含有化学物质的饮食时，RNAi 介导的 CYP9A10 沉默在 48 小时时进一步增加了 18%、26% 和 35% 的死亡率，在 72 小时时增加了 27%、43% 和 55%。结果表明，CYP9A10 可能在甜菜叶黄素和α-氯氰菊酯解毒中起重要作用。RNAi 介导的沉默可以为害虫控制或杀虫剂抗性管理提供有效的协同剂。与对照相比，当幼虫暴露于含有化学物质的饮食时，72 小时时分别为 43% 和 55%。结果表明，CYP9A10 可能在甜菜叶黄素和α-氯氰菊酯解毒中起重要作用。RNAi 介导的沉默可以为害虫控制或杀虫剂抗性管理提供有效的协同剂。与对照相比，当幼虫暴露于含有化学物质的饮食时，72 小时时分别为 43% 和 55%。结果表明，CYP9A10 可能在甜菜叶黄素和α-氯氰菊酯解毒中起重要作用。RNAi 介导的沉默可以为害虫控制或杀虫剂抗性管理提供有效的协同剂。