As one of the most important detoxification enzymes in insects, Glutathione S-transferases (GSTs) play key roles in insecticide resistance via direct metabolism and protection against oxidative stress induced by insecticide exposure. Insect GSTs are often considered as the phase II detoxification enzymes, they have potential function to metabolize fipronil as well as its fipronil's metabolites. In the fipronil-resistant Nilaparvata lugens strain G28, GSTs' inhibitor DEM (diethyl maleate) showed the optimal synergistic effects (5.73-fold), indicating the essential roles of GSTs in the resistance to fipronil in this insect species. Four GST genes, NlGSTs1, NlGSTs2, NlGSTe1 and NlGSTd1, were found over-expressed in G28 when compared to its relative susceptible counterpart strain S28. The roles of these four GSTs in fipronil resistance were confirmed via RNAi. The four GST genes were highly over-expressed in the midgut and/or fat body with detoxification action, which might provide more chances for insects to metabolize fipronil and its metabolites. Additionally, the higher induction levels in the GST gene expression by insecticides in the midgut and/or fat body compared to the whole insect also supported the significant roles of the four GSTs in the detoxification. Above all, the results provided evidences to understand the functions of GSTs in fipronil resistance in N. lugens, and gave a reference for other insects in fipronil resistance.

作为昆虫中最重要的解毒酶之一，谷胱甘肽 S-转移酶 (GST) 通过直接代谢和保护免受杀虫剂暴露引起的氧化应激，在杀虫剂抗性中发挥关键作用。昆虫 GSTs 通常被认为是 II 相解毒酶，它们具有代谢氟虫腈及其代谢物的潜在功能。在耐氟虫腈Nilaparvata lugens菌株 G28 中，GSTs 的抑制剂 DEM（马来酸二乙酯）表现出最佳协同效应（5.73 倍），表明 GSTs 在该昆虫物种对氟虫腈的抗性中的重要作用。四个 GST 基因，NlGSTs1、NlGSTs2、NlGSTe1和NlGSTd1，与相对易感的对应菌株 S28 相比，发现在 G28 中过度表达。这四种 GST 在氟虫腈抗性中的作用通过 RNAi 得到证实。4个GST基因在具有解毒作用的中肠和/或脂肪体中高表达，这可能为昆虫代谢氟虫腈及其代谢物提供更多机会。此外，与整个昆虫相比，杀虫剂在中肠和/或脂肪体中对 GST 基因表达的更高诱导水平也支持四种 GST 在解毒中的重要作用。最重要的是，该结果为了解GSTs在N. lugens对氟虫腈抗性中的作用提供了依据，并为其他昆虫对氟虫腈的抗性提供了参考。