Adipokinetic hormone (AKH), the principal stress‐responsive neurohormone in insects, has been implicated in insect responses to insecticides. However, the functionality of AKH and its mode of signalling in insecticide resistance are unknown. Herein, we demonstrated that the enhanced activity of carboxylesterases (CarEs) is involved in the chlorpyrifos resistance in Nilaparvata lugens [brown planthopper (BPH)]. Chlorpyrifos exposure significantly induced the expression of AKH and its receptor AKHR in the susceptible BPH (Sus), and these two AKH signalling genes were over‐expressed in the chlorpyrifos‐resistant strain (Res) compared to Sus. RNA interference (RNAi) against AKH or AKHR decreased the CarE activity and suppressed the BPH's resistance to chlorpyrifos in Res. Conversely, AKH peptide injection elevated the CarE activity and enhanced the BPH's survival against chlorpyrifos in Sus. Furthermore, five CarE genes were identified to be positively affected by the AKH pathway using RNAi and AKH injection. Among these CarE genes, CarE and Esterase E4‐1 were found to be over‐expressed in Res compared to Sus, and knockdown of either gene decreased the BPH's resistance to chlorpyrifos. In conclusion, AKH plays a role in enhancing chlorpyrifos resistance in the BPH through positive influence on the expression of CarE genes and CarE enzyme activity.

中文翻译：

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脂肪代谢激素增强褐飞虱Nilaparvata lugens中CarE介导的毒死rif的抗性。

促脂激素（AKH）是昆虫中主要的应激反应性神经激素，与昆虫对杀虫剂的反应有关。但是，AKH的功能及其在杀虫剂抗性方面的信号传导模式尚不清楚。在本文中，我们证明了增强的羧酸酯酶（CarEs）活性与褐飞虱[褐飞虱（BPH）]的毒死rif抗性有关。毒死rif暴露显着诱导易感性BPH（Sus）中AKH及其受体AKHR的表达，与Sus相比，这两个AKH信号基因在耐毒死rif菌株（Res）中过表达。针对AKH或AKHR的RNA干扰（RNAi）降低了CarE活性并抑制了BPH对Res中毒死rif的抗性。相反，注射AKH肽可以提高CarE活性，并提高BPH对Sus中毒死rif的存活率。此外，使用RNAi和AKH注射，鉴定出五个CarE基因受到AKH途径的正影响。在这些CarE基因中，发现与Sus相比，CarE和Esterase E4-1在Res中过表达，而敲除这两个基因都会降低BPH对毒死rif的抗性。总之，AKH通过对CarE基因表达和CarE酶活性的积极影响，在增强BPH中的毒死rif抗性中发挥作用。