Wang Shuai, Xie Yuan, Liu Chong, Liu Jin-Wei, Guo Fang-Rui, Qiao Song-Tao, Xing Yu-Ji, Wu Shun-Fan, Bass Chris, Gao Cong-Fen
College of Plant Protection, Nanjing Agricultural University, State Key Laboratory of Agricultural and Forestry Biosecurity, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Weigang Road 1, Nanjing, 210095, Jiangsu, China.
College of Plant Protection, Nanjing Agricultural University, State Key Laboratory of Agricultural and Forestry Biosecurity, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Weigang Road 1, Nanjing, 210095, Jiangsu, China.
Insect Biochem Mol Biol. 2025 Aug;182:104357. doi: 10.1016/j.ibmb.2025.104357. Epub 2025 Jul 4.
Abamectin serves as a key alternative for managing diamide-resistant Chilo suppressalis. However, resistance to abamectin itself presents a significant challenge to this pest control, and its genetic basis remains poorly understood. In this study, we report an increase in field resistance to abamectin in populations of C. suppressalis and provide evidence for a cytochrome P450-mediated metabolic resistance mechanism, supported by enzyme activity assays and synergist bioassays. Transcriptomic profiling analysis revealed six candidate P450 genes, among which the duplicated gene CYP6SN2 showed a strong correlation with resistance. Variant CYP6SN2vB was highly expressed in detoxification tissues and mainly produced isoforms with a short 3'-UTR. Functional validation in transgenic Drosophila melanogaster confirmed that overexpression of CYP6SN2vB conferred 2.4- and 1.9-fold resistance to abamectin and emamectin benzoate, whereas CYP6SN2vA had no detectable effect. Molecular docking further revealed that CYP6SN2vB could potentially hydroxylate abamectin via interactions near oxygen-binding motifs. In contrast, the inward-folded substrate recognition site 1 region of CYP6SN2vA compresses the ligand-binding cavity, precluding abamectin interaction. These findings suggest neofunctionalization of CYP6SN2vB following duplication and provide valuable insights into the molecular basis of abamectin resistance in C. suppressalis, with implications for resistance management.
阿维菌素是防治对双酰胺类杀虫剂产生抗性的二化螟的关键替代药剂。然而，二化螟对阿维菌素本身产生的抗性给害虫防治带来了重大挑战，其遗传基础仍不清楚。在本研究中，我们报道了二化螟种群对阿维菌素田间抗性的增加，并通过酶活性测定和增效剂生物测定，为细胞色素P450介导的代谢抗性机制提供了证据。转录组分析揭示了6个候选P450基因，其中重复基因CYP6SN2与抗性密切相关。变异体CYP6SN2vB在解毒组织中高表达，主要产生3'-UTR短的异构体。在转基因黑腹果蝇中的功能验证证实，CYP6SN2vB的过表达使果蝇对阿维菌素和甲氨基阿维菌素苯甲酸盐的抗性分别提高了2.4倍和1.9倍，而CYP6SN2vA没有可检测到的影响。分子对接进一步表明，CYP6SN2vB可能通过与氧结合基序附近的相互作用使阿维菌素羟基化。相比之下，CYP6SN2vA向内折叠的底物识别位点1区域压缩了配体结合腔，阻止了与阿维菌素的相互作用。这些发现表明重复后的CYP6SN2vB发生了新功能化，为二化螟对阿维菌素抗性的分子基础提供了有价值的见解，对抗性治理具有重要意义。
