Susceptibility to insecticides is one of the limiting factors preventing wider adoption of natural enemies to control insect pest populations. Identification and selective breeding of insecticide tolerant strains of commercially used biological control agents (BCAs) is one of the approaches to overcome this constraint. Although a number of beneficial insects have been selected for increased tolerance to insecticides the molecular mechanisms underpinning these shifts in tolerance are not well characterised. Here we investigated the molecular mechanisms of enhanced tolerance of a lab selected strain of (Fieber) to the commonly used biopesticide spinosad. Transcriptomic analysis showed that spinosad tolerance is not a result of overexpressed detoxification genes. Molecular analysis of the target site for spinosyns, the nicotinic acetylcholine receptor (nAChR), revealed increased expression of truncated transcripts of the nAChR α6 subunit in the spinosad selected strain, a mechanism of resistance which was described previously in insect pest species. Collectively, our results demonstrate the mechanisms by which some beneficial biological control agents can evolve insecticide tolerance and will inform the development and deployment of insecticide-tolerant natural enemies in integrated pest management strategies.

中文翻译：

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烟碱乙酰胆碱受体 α 6 亚基的异常剪接与蓟马捕食者 Orius laevigatus 的多杀菌素耐受性相关

对杀虫剂的敏感性是阻碍更广泛采用天敌来控制害虫种群的限制因素之一。商业使用的生物防治剂（BCA）的杀虫剂耐受菌株的鉴定和选育是克服这一限制的方法之一。尽管已经选择了许多有益昆虫来提高对杀虫剂的耐受性，但支撑这些耐受性转变的分子机制尚未得到很好的表征。在这里，我们研究了实验室选定的菌株（Fieber）对常用生物农药多杀菌素增强耐受性的分子机制。转录组分析表明，多杀菌素耐受性并不是解毒基因过度表达的结果。对多杀菌素的靶位点烟碱乙酰胆碱受体（nAChR）进行的分子分析表明，在多杀菌素选择的菌株中，nAChR α6亚基的截短转录本的表达增加，这是先前在昆虫害虫物种中描述的一种抗性机制。总的来说，我们的结果证明了一些有益的生物防治剂可以进化出杀虫剂耐受性的机制，并将为综合害虫管理策略中耐杀虫剂天敌的开发和部署提供信息。