Investigating resistance to neonicotinoid insecticides in insect pests

自拟除虫菊酯商业化以来，新烟碱类杀虫剂是用于害虫管理的增长最快的一类杀虫剂。据估计，它们在全球的销售额每年已超过10亿美元。这些新颖、安全和高效的化合物为害虫对早期使用的化学品的抗性问题提供了宝贵的缓解，但它们本身非常容易受到新抗性机制的出现。广泛建立类烟碱抗性将严重损害包括英国在内的世界许多地区作物保护战略的环境和经济可持续性。褐稻虱（Nilaparvata lugens）和烟粉虱（Bemisia tabaci）是迄今为止相对较少的对类烟碱产生强烈抗性的两个物种。这些物种是分析潜在机制及其实际影响的理想模型，也是对更广泛的害虫物种的潜在问题发出预警的理想模型。关于能够保护免受类尼古丁的机制仍然知之甚少。然而，在N.我们已经鉴定了烟碱乙酰胆碱受体（nAChR）中的突变，所述烟碱乙酰胆碱受体（nAChR）是昆虫神经系统中被类烟碱靶向的蛋白质，其极大地降低了杀虫剂与受体之间的结合，并且在全生物体生物测定中赋予显著降低的敏感性。由于其他杀虫剂类别的靶点抗性突变通常被证明在不同物种之间是相同的，因此来自稻飞虱的结果可能会转移到类烟碱的其他主要靶标。该项目将利用已建立的国际监测网络获取N. lugens，B.烟粉虱、桃蚜（桃蚜-马铃薯蚜虫）和猫栉首蚤（猫蚤）的抗性表型表征和可能的靶位点抗性机制的分子表征。后者将包括膜结合研究和nAChR基因的测序，以检测与结合减少相关的突变puronectin，以及研究这种关联的表达研究。基于这些发现，我们将开发和验证高通量的基于DNA的检测方法，用于诊断单个昆虫的抗性突变，以监测其发病率并帮助制定抗性管理策略。

Neonicotinoids represent the fastest-growing class of insecticides introduced for pest management since the commercialisation of pyrethroids. Their sales worldwide are already estimated to exceed one billion US dollars per year. These novel, safe and highly effective compounds provide a invaluable respite from problems of pest resistance to earlier-used chemicals, but are themselves very vulnerable to appearance of new resistance mechanisms. Widespread establishment of neonicotinoid resistance would severely compromise the environmental and economic sustainability of crop protection strategies in many parts of the world including the UK. The brown rice planthopper (Nilaparvata lugens) and the tobacco whitefly (Bemisia tabaci) are two of the relatively few species to have developed strong neonicotinoid resistance to date. Such species serve as ideal models for analysing the underlying mechanisms and their practical implications, and for forewarning of potential problems in a wider range of pest species. Little is still known about the mechanisms that could confer protection from neonicotinoids. However, in N. lugens we have identified a mutation in the nicotinic acetylcholine receptor (nAChR), the protein in the insect nervous system targeted by neonicotinoids, which greatly reduces binding between insecticides and the receptor and confers substantially reduced susceptibility in whole-organism bioassays. Since target-site resistance mutations for other insecticide classes have often proved to be identical across species, results from planthoppers are likely to be transferable to other major targets of neonicotinoids. This project will exploit established, international monitoring networks to obtain samples of N. lugens, B. tabaci, Myzus persicae (peach-potato aphid) and Ctenocephalides felis (cat flea) from areas of intensive neonicotinoid use for phenotypic characterisation of resistance and molecular characterisation of possible target-site resistance mechanisms. The latter will include membrane binding studies and sequencing of nAChR genes to detect mutations putatively associated with reduced binding, and expression studies to investigate such an association. Based on these findings we will develop and validate high throughput DNA-based assays for diagnosing resistance mutations in individual insects in order to monitor their incidence and aid resistance management strategies.