CYP6CW1及分子变异介导的灰飞虱抗噻嗪酮机理研究

Buprofezin is the thiadiazine insect growth regulators (IGRs), which has effectively controls harmful insect pests, including rice planthopper, etc. The results of field monitoring indicated that Laodelphax striatellus (Fallén) had developed different resistance levels against buprofezin in the natural populations. But in all cases reported to date, the study of resistance mechanisms to buprofezin has not been systematically carried out. According to preliminary research results that significantly overexpressed (22.78-fold) cytochrome P450 gene (CYP6CW1) of L. striatellus in the buprofezin-resistant stain was linked to the buprofezin resistance and the establishment of nearly isogenic buprofezin resistant and susceptible strains of L. striatellus, we intend to further carry out the study of resistance mechanisms of buprofezin on two aspects. (1) Using the overexpressed regulation of CYP6CW1, tissue expression, the alignment of coding region sequences between resistant and susceptible strains, resistance functional verification via RNAi and detoxification function analysis, the role of CYP6CW1 in buprofezin resistance will be further clarified. (2) The transcriptome sequencing between nearly isogenic buprofezin resistant and susceptible strains of L. striatellus as basis, buprofezin resistance mechanism that mediated by molecular variation, including epidermal penetration and transportation, detoxification, energy metabolism, anti-stress, immune pathway and interaction of potential target, will be studied. The research results not only defined the buprofezin detoxification metabolism resistance that mediated by CYP6CW1, but also enriched molecular resistance mechanism of buprofezin in insect.

噻嗪酮为噻二嗪类昆虫生长调节剂（IGRs），其对稻飞虱等害虫具有优良的防治效果。田间监测表明灰飞虱对噻嗪酮已产生不同程度的抗性，目前国内外对噻嗪酮的抗性机理研究还未系统开展。为此，本项目依据前期发现灰飞虱细胞色素P450基因（CYP6CW1）在噻嗪酮抗性品系中显著过量表达（22.78倍）与噻嗪酮抗性存在联系及遗传背景相似的灰飞虱抗、感噻嗪酮品系建立的基础上，分别从两方面深入开展噻嗪酮抗性机理研究：（1）CYP6CW1 过量表达调控、组织表达、编码区序列比对、RNAi功能验证和代谢功能分析方面进一步研究CYP6CW1在噻嗪酮抗性中的作用；（2）基于灰飞虱抗、感噻嗪酮品系转录组测序为基础，探究分子变异所介导的杀虫剂表皮穿透及转运、解毒代谢、抗胁迫、免疫途径和潜在靶标互作等抗性机制。这些研究结果不仅明确了重要解毒代谢因子CYP6CW1所介导的噻嗪酮抗性机理，而且丰富了昆虫抗噻嗪酮的分子抗性机制。

抗药性是制约杀虫剂田间有效害虫防控的最大屏障，开展杀虫剂抗性研究能有效为害虫抗性治理提供重要的理论支撑。本项目以水稻重要害虫灰飞虱和一种长期防控稻飞虱的昆虫生长调节剂噻嗪酮为研究对象，发现细胞色素P450电子供体NADPH细胞色素P450还原酶在噻嗪酮抗性中发挥着重要的作用，过量表达的灰飞虱CYP6CW1广泛参与田间噻嗪酮抗性，并且其是田间造成吡蚜酮和噻嗪酮交互抗性的重要因子。通过对灰飞虱抗、感噻嗪酮品系基因和蛋白表达谱分析发现一些与噻嗪酮抗性相关的重要量变因子，如羧酸酯酶，热激蛋白70，气味结合蛋白和表皮蛋白等。本文研究结果将为田间抗性监测及抗性治理提供重要的分子基础。