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

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