文献类型： 外文期刊

第一作者： Wu, Choufei

作者： Wu, Choufei;Wu, Xiaoying;Zhang, Liqin;Ding, Chaohui;Li, Wu;Ding, Chaohui;Wu, Xiaoying;Song, Yuanyuan;Zeng, Rensen;Chen, Shi

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关键词： Helicoverpa armigera; plant volatile; herbivore-induced plant volatiles cytochrome P450 monooxygenases; insecticide tolerance; detoxification enzyme

期刊名称：INSECTS （ 影响因子：2.22； ）

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年卷期： 2021 年 12 卷 3 期

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收录情况： SCI

摘要： Simple Summary Upon insect herbivory plants release herbivore-induced plant volatiles (HIPVs) to elicit either direct antiherbivore defenses by intoxicating the herbivore or indirect defenses by attracting natural enemies. Insect herbivores use sophisticated detoxification systems, including cytochrome P450 monooxygenases (P450s), to cope with plant defensive chemicals and insecticides. Many behaviors of insects are manipulated to a large extent by olfaction. However, few studies concern the role of olfaction in insect adaptation to xenobiotics. In this study we show that olfactory exposure of Helicoverpa armigera, a devastating pest of many important crop plants that has developed high levels of resistance to various insecticides, to four plant volatile compounds limonene, nerolidol, 2-heptanone and cis-3-hexenyl acetate dramatically increases larval tolerance to carbamate insecticide methomyl. Inhibition of P450s by piperonyl butoxide (PBO), a well-known P450 inhibitor, compromises the effects of volatile exposure. Exposure to the four volatiles upregulates multiple detoxification systems, including cytochrome P450s. Our findings indicate that induction of insecticide-detoxifying P450s by plant volatiles prior to actually inflicting plant damage may confer insect larvae more time to pre-activate insect detoxification systems prior to the ingestion or contact of insecticides, leading to increased larval tolerance to insecticides. Plants release an array of volatile chemicals into the air to communicate with other organisms in the environment. Insect attack triggers emission of herbivore-induced plant volatiles (HIPVs). How insect herbivores use these odors to plan their detoxification systems is vital for insect adaptation to environmental xenobiotics. Here we show that the larvae of Helicoverpa armigera (Hubner), a broadly polyphagous lepidopteran herbivore, have the capacity to use plant volatiles as cues to upregulate multiple detoxification systems, including cytochrome P450 monooxygenases (P450s), for detoxification of insecticides. Olfactory exposure of the fifth instars to two terpene volatiles limonene and nerolidol, and two green-leaf volatiles 2-heptanone and cis-3-hexenyl acetate significantly reduced larval susceptibility to the insecticide methomyl. However, larval pretreatment with piperonyl butoxide (PBO), a known P450 inhibitor, neutralized the effects of volatile exposure. Furthermore, larval exposure to the four plant volatiles enhanced activities of P450 enzymes in midguts and fatbodies, and upregulated expression of CYP6B2, CYP6B6 and CYP6B7, P450s involved in detoxification of the insecticide. Larval exposure to 2-heptanone and limonene volatiles also enhanced activities of glutathione-s-transferase and carboxylesterase. Our findings suggest that olfactory exposure to HIPVs enhances larval insecticide tolerance via induction of detoxification P450s.

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