Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA.
Genomics and Sequencing Laboratory, Auburn University, Auburn, Alabama, USA.
Insect Sci. 2018 Jun;25(3):439-453. doi: 10.1111/1744-7917.12438. Epub 2017 Apr 11.
Insecticide resistance is a major obstacle to the management of disease-vectoring mosquitoes worldwide. The genetic changes and detoxification genes involved in insecticide resistance have been extensively studied in populations of insecticide-resistant mosquitoes, however few studies have focused on the resistance genes upregulated upon insecticide exposure and the possible regulation pathways involved in insecticide resistance. To characterize the changes in gene expression during insecticide exposure, and to investigate the possible connection of known regulation pathways with insecticide resistance, we conducted RNA-Seq analysis of a highly permethrin-resistant strain of Culex quinquefasciatus following permethrin exposure. Gene expression profiles revealed a total of 224 upregulated and 146 downregulated genes when compared to a blank acetone carrier treated control, respectively, suggesting that there were multiple, but specific genes involved in permethrin resistance. Functional enrichment analysis showed that the upregulated genes contained multiple detoxification genes including a glutathione S-transferase and multiple cytochrome P450 genes, as well as several immune-related genes, while the downregulated genes consisted primarily of proteases and carbohydrate metabolism and transport. Further analysis showed that permethrin exposure resulted in a decrease in the expression of serum storage proteins and likely represented a delay in the development of the fourth instar possibly due to a decrease in feeding. This effect was more pronounced in an insecticide-resistant strain than in an insecticide-susceptible strain and may represent a behavioral mechanism of insecticide resistance in Culex mosquitoes.
昆虫抗药性是全球病媒蚊管理的主要障碍。在抗药性蚊虫种群中，已广泛研究了与杀虫剂抗性相关的遗传变化和解毒基因，但很少有研究关注杀虫剂暴露后上调的抗性基因以及与杀虫剂抗性相关的可能调控途径。为了描述杀虫剂暴露过程中基因表达的变化，并研究已知调控途径与杀虫剂抗性的可能联系，我们对经拟除虫菊酯高度抗性的致倦库蚊进行了 RNA-Seq 分析，然后用拟除虫菊酯处理。与空白丙酮载体处理的对照相比，基因表达谱显示总共有 224 个上调基因和 146 个下调基因，表明有多个但特定的基因参与了拟除虫菊酯抗性。功能富集分析表明，上调的基因包含多个解毒基因，包括谷胱甘肽 S-转移酶和多个细胞色素 P450 基因，以及几个免疫相关基因，而下调的基因主要由蛋白酶和碳水化合物代谢和运输组成。进一步的分析表明，拟除虫菊酯暴露导致血清储存蛋白的表达降低，可能导致第四龄期的发育延迟，可能是由于进食减少。这种影响在抗药性品系中比在敏感性品系中更为明显，可能代表了库蚊中杀虫剂抗性的一种行为机制。
