基于kdr负交互抗性的植物源杀虫化合物haedoxan A作用位点的研究

前期研究发现植物源杀虫化合物haedoxan A(HA)对击倒抗性(kdr)昆虫具负交互抗性。虽然HA作用于昆虫钠通道，引起失活电压向超极化方向显著移动，但其作用机理明显不同于已知的昆虫钠通道神经毒剂（包括拟除虫菊酯类和钠通道阻断杀虫剂），因而推测 HA 在钠通道上有一个独特的与拟除虫菊酯类结合位点别构偶联的结合位点。本研究拟应用分子定点突变技术与爪蟾卵母细胞异源表达的双电极电压钳技术，结合同源建模和分子对接，预测 HA 在蟑螂钠通道BgNaV1-1a上的作用位点，并通过点突变对这一新的结合位点进行功能验证，阐明 HA 的作用机理，为开发作用于昆虫钠通道特异位点的新型杀虫剂奠定基础。

Previous studies found that botanical insecticidal compound haedoxan A(HA) has significantly negative cross resistance to knock down resistance (kdr) insects. Although HA acted on the insect voltage gating sodium channels and caused to inactivation voltage shifted to hyperpolarizing direction, the mode of action of HA is different from those of other sodium channels neurotoxins including pyrethroids and sodium channel block insecticides (SCBIs). Our hypothesis is that HA acts on a unique binding site in sodium channels, which is allosterically coupled with pyrethroid binding site. Therefore, using site-directed mutagenesis and two electrode voltage clamp recording technique based on Xenopus oocyte of heterologous expression of mutant channels in cockroach BgNaV1-1a sodium channel, combining with homology modeling and molecular docking, and functional verification of the predicted target sites, this program intends to identify the binding site of HA acting on BgNaV1-1a, to elucidate the action mode of HA. Elucidation of the mode of action of HA and identification of the HA receptor sites would provide a structural background for the rational design of new and more potent insecticides.