Deltamethrin-resistance In Culex Pipiens Pallens:Presumptive Role For The Cuticle Protein

Background:Chemical control has been the main method in comprehensive management strategy applied worldwide in mosquito vector control. Large-scale use of insecticides has led to an undesired insecticide-resistance in mosquito populations. This study aimed to investigate the deltamethrin-resistance mechanism associated with ICPs (insect cuticle proteins, ICPs) and CHSI (chitin synthase I, CHSI).Methods:Differentially accumulated ICPs based on insecticide-resistance proteomes and transcriptomes were identified in the deltamethrin-resistant (DR) and-susceptible (DS) strains of Culex pipiens pallens. The different messenger RNA expression levels of the ICPs and CHSI were detected in the DS and DR strains in laboratory and field populations in the using of qRT-PCR; the effect of short-term exposure of the deltamethrin-susceptible strain to deltamethrin was also measured; cloning the full-length cDNA of Unigene3941_All gene, homology analysis and phylogenetic analysis were carried out with some other insect; furthermore, siRNA was used to knockdown the expression level of Unigene3941-All for characterizing the contribution of Unigene3941-All to deltamethrin-resistance.Results:The results show that ICPs and CHSI were differentially expressed between DS and DR strain in laboratory and field populations; the expression level of Unigene3941_All was found to be far higher than that of other13ICPs:the ratio of Unigene3941_All gene were10.78%and73.95%in DS and DR strain, respectively; the knockdown of Unigene3941-All gene increased the susceptibility of the deltamethrin-resistant strain, while the expression level of other13ICPs elevated; in the study of the response to deltamethrin, the highest expression level for ICPs and CHSI occurred at12or24h after exposure, and then decreased rapidly over the next few hours; the full-length cDNA of Unigene3941_All was732bp, with the ORF of390bp and129amino acids (GenBank/KF723314,2013)Conclusions:This study provides compelling evidence that ICPs and CHSI are associated with insecticide-resistance, the Unigene3941_All gene plays a dominant role in insecticide-resistance, and. there maybe some regulate mechanism in ICPs.