褐飞虱对吡虫啉的抗性机理和靶标分子毒理学

Imidacloprid resistance mechanisms in Nilaparvata lugens and pharmacological properties of its nicotinic acetylcholine receptors

褐飞虱Nilaparvata lugens是水稻最重要的害虫之一,长期依赖化学防治导致了该害虫对不同类型杀虫剂抗性的产生,对新烟碱类杀虫剂吡虫啉高水平抗性的产生更是造成了巨大的粮食生产损失。近年来在褐飞虱对吡虫啉抗性机理,以及在抗药性机理研究推动下吡虫啉作用靶标褐飞虱神经系统烟碱型乙酰胆碱受体(nicotinic acetylcholine receptors,nAChRs)毒理学等方面取得了许多研究进展。nAChRs是昆虫神经系统中最重要的神经递质受体,是几类重要杀虫剂的作用靶标,其中以新烟碱类杀虫剂为代表。通过对比敏感品系和室内连续筛选获得的高抗吡虫啉品系,在褐飞虱两个nAChRs亚基Nlα1和Nlα3中均发现了抗性相关点突变Y151S,该突变导致了受体与吡虫啉结合亲和力的显著下降,而对内源神经递质乙酰胆碱的亲和力影响很小。Nlα1与褐飞虱另外两个亚基Nlα2和Nlβ1共聚成一个受体,构成吡虫啉低亲和力结合位点;Nlα3与褐飞虱另外两个亚基Nlα8和Nlβ1共聚成一个受体,构成吡虫啉高亲和力结合位点。不仅褐飞虱nAChRs与吡虫啉抗性相关,某些nAChRs附属蛋白也直接影响褐飞虱对吡虫啉的抗性,如Lynx蛋白。关于褐飞虱nAChRs组成、抗药性相关变异、受体附属蛋白对抗药性的影响等方面的研究,均为国内外前沿报道,不仅有助于对新烟碱类杀虫剂抗性机理的理解,对昆虫nAChRs毒理学同样具有很大的推动作用。

The brown planthopper,Nilaparvata lugens,is a major rice pest in many parts of Asia.Insecticides have been extensively used for its control,and resistance to various insecticides in this species has been reported in different countries and areas.The resistance to imidacloprid,a neonicotinoid insecticide,in N.lugens had caused big loss in rice production in recent years.Meantime,great progresses have been achieved in its imidacloprid resistance mechanisms and nicotinic acetylcholine receptors （nAChRs）,the target of neonicotinoid insecticides.NAChR is an important neurotransmitter receptor in insect central nervous system,which makes it become the important target to several kinds of insecticides,including neonicotinoid insecticides extensively used to control N.lugens in recent years.The Y151S mutation had been identified in two N.lugens nAChRs α subunits,Nlα1 and Nlα3,which have distinct influence on imidacloprid affinity,but little influence on acetylcholine.Nlα1,Nlα2 and Nlβ1 are co-assembled into one receptor,which constitutes the lower affinity binding site for imidacloprid in N.lugens,while Nlα3,Nlα8 and Nlβ1 are co-assembled into another receptor,which constitutes the higher affinity binding site.Imidacloprid resistance was found not only related to insect nAChRs,but also influenced by insect nAChRs accessory protein,such as lynx proteins in N.lugens,the insect nAChRs modulators.Most achievements mentioned here were newly reported,and are important to understand the resistance mechanisms to neonicotinoid insecticides and the pharmacological properties of insect nAChRs.