Function of G-protein-coupled receptor signaling-pathway-related genes in insecticide resistance of mosquitoes, Culex quinquefasciatus

G-protein-coupled receptor (GPCR) signal transduction pathways have crucial physiological functions in insects. Our recent studies have, for the first time, identified the role of an overexpressed GPCR gene in permethrin resistant mosquitoes of Culex quinquefasciatus through the regulation of resistance-related P450 gene expression. To further explore the unknown functions of GPCR-mediated signaling pathways in the insecticide resistant mosquitoes, we characterized the gene expression profiles of 128 GPCR signaling-pathway-related genes at the whole transcriptome level in permethrin-resistant and susceptible Culex mosquito strains using qPCR. Seven GPCR signaling-pathway-related genes were significantly overexpressed in the larvae and adults of the highly resistant Culex strains of HAmCq^G8 and MAmCq^G6. We further characterized the function of the GPCR signaling pathway in insecticide resistance using the double-stranded RNA-mediated gene interference (RNAi) technique. Our study showed that knockdown of the expression of GPCR-signaling-pathway-related genes in resistant mosquitoes caused a significant reduction in the mosquitoes’ resistance to permethrin, strongly suggesting the involvement of the GPCR signaling pathway in pyrethroid resistance development in mosquitoes. The study sheds new light on the molecular basis of GPCR signaling pathways in the evolution of insecticide resistance in mosquitoes, and is fundamental for designing novel strategies to control mosquitoes, especially resistant ones.