Transcriptome and Functional Analyses Revealed the Carboxylesterase Genes Involved in Pyrethroid Resistance in Anopheles sinensis (Diptera: Culicidae)

Abstract

Carboxylesterases (CCEs) have been demonstrated to be involved in pyrethroid resistance in insect species. This study aims to investigate CCE-mediated resistance mechanisms in Anopheles sinensis, a major malaria vector. Through comparative transcriptomics of a deltamethrin-resistant strain (CQ-LR) versus susceptible strain (WX-LS) of An. sinensis, we identified differentially expressed CCE genes across five developmental stages, five tissues, and three time points post-blood-meal. Four candidate genes (AsAe9, AsAe10, AsAce2, AsUn5) showed significantly upregulated expression. Subsequent qRT-PCR validation across four field-derived resistant strains (WX-LR, AH-LR, YH-LR, CQ-LR) and the susceptible strain confirmed significant upregulation of AsAe9, AsAe10, AsAce1, AsAce2, and AsBe4 in more than two resistant populations. RNAi-based functional validation showed that silencing AsAe10 or AsBe4 in the WX-LR strain significantly decreased knockdown time and raised 24 h mortality upon diagnostic deltamethrin exposure, with AsAe10 silencing having the strongest effect. This study identifies CCE genes involved in deltamethrin resistance in An. sinensis, providing valuable insights into the resistance mechanisms of pyrethroid and a theoretical basis for mosquito resistance management.