Perkin Lindsey C, Cohen Zachary P, Carlson Jason W, Suh Charles P-C
Insect Control and Cotton Disease Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, 2771 F and B Road, College Station, TX 77845, USA.
Center for Plant Health Science and Technology, Plant Protection and Quarantine, Animal Plant Health Inspection Service, United States Department of Agriculture, 22675 N. Moorefield Rd Bldg. 6414, Edinburg, TX 78541, USA.
Insects. 2023 Feb 16;14(2):197. doi: 10.3390/insects14020197.
Insecticide tolerance and resistance have evolved countless times in insect systems. Molecular drivers of resistance include mutations in the insecticide target site and/or gene duplication, and increased gene expression of detoxification enzymes. The boll weevil, Boheman (Coleoptera: Curculionidae), is a pest of commercial cotton and has developed resistance in the field to several insecticides; however, the current organophosphate insecticide, malathion, used by USA eradication programs remains effective despite its long-term use. Here, we present findings from an RNA-seq experiment documenting gene expression post-exposure to field-relevant concentrations of malathion, which was used to provide insight on the boll weevil's continued susceptibility to this insecticide. Additionally, we incorporated a large collection of boll weevil whole-genome resequencing data from nearly 200 individuals collected from three geographically distinct areas to determine SNP allele frequency of the malathion target site, as a proxy for directional selection in response to malathion exposure. No evidence was found in the gene expression data or SNP data consistent with a mechanism of enhanced tolerance or resistance adaptation to malathion in the boll weevil. Although this suggests continued effectiveness of malathion in the field, we identified important temporal and qualitative differences in gene expression between weevils exposed to two different concentrations of malathion. We also identified several tandem isoforms of the detoxifying esterase B1 and glutathione S-transferases, which are putatively associated with organophosphate resistance.
在昆虫系统中，杀虫剂耐受性和抗性已经进化了无数次。抗性的分子驱动因素包括杀虫剂靶位点的突变和/或基因复制，以及解毒酶基因表达的增加。棉铃象甲，Boheman（鞘翅目：象甲科），是商业棉花的一种害虫，并且已经在田间对几种杀虫剂产生了抗性；然而，美国根除计划目前使用的有机磷杀虫剂马拉硫磷尽管长期使用，但仍然有效。在这里，我们展示了一项RNA测序实验的结果，该实验记录了暴露于与田间相关浓度的马拉硫磷后的基因表达情况，以此来深入了解棉铃象甲对这种杀虫剂持续的敏感性。此外，我们纳入了大量来自三个地理上不同区域收集的近200个个体的棉铃象甲全基因组重测序数据，以确定马拉硫磷靶位点的单核苷酸多态性（SNP）等位基因频率，作为对马拉硫磷暴露的定向选择的代理指标。在基因表达数据或SNP数据中均未发现与棉铃象甲对马拉硫磷耐受性增强或抗性适应机制一致的证据。虽然这表明马拉硫磷在田间仍有效果，但我们发现暴露于两种不同浓度马拉硫磷的象甲之间在基因表达上存在重要的时间和定性差异。我们还鉴定出了解毒酯酶B1和谷胱甘肽S -转移酶的几种串联异构体，它们可能与有机磷抗性有关。
