The Transcriptome Profile of the Mosquito Culex quinquefasciatus following Permethrin Selection

Abstract

To gain valuable insights into the gene interaction and the complex regulation system involved in the development of insecticide resistance in mosquitoes Culex quinquefasciatus, we conducted a whole transcriptome analysis of Culex mosquitoes following permethrin selection. Gene expression profiles for the lower resistant parental mosquito strain HAmCqG0 and their permethrin-selected high resistant offspring HAmCqG8 were compared and a total of 367 and 3982 genes were found to be up- and down-regulated, respectively, in HAmCqG8, indicating that multiple genes are involved in response to permethrin selection. However, a similar overall cumulative gene expression abundance was identified between up- and down-regulated genes in HAmCqG8 mosquitoes following permethrin selection, suggesting a homeostatic response to insecticides through a balancing of the up- and down-regulation of the genes. While structural and/or cuticular structural functions were the only two enriched GO terms for down-regulated genes, the enriched GO terms obtained for the up-regulated genes occurred primarily among the catalytic and metabolic functions where they represented three functional categories: electron carrier activity, binding, and catalytic activity. Interestingly, the functional GO terms in these three functional categories were overwhelmingly overrepresented in P450s and proteases/serine proteases. The important role played by P450s in the development of insecticide resistance has been extensively studied but the function of proteases/serine proteases in resistance is less well understood. Hence, the characterization of the functions of these proteins, including their digestive, catalytic and proteinase activities; regulation of signaling transduction and protein trafficking, immunity and storage; and their precise function in the development of insecticide resistance in mosquitoes will provide new insights into how genes are interconnected and regulated in resistance.

Permethrin Induction of Multiple Cytochrome P450 Genes in Insecticide Resistant Mosquitoes, Culex quinquefasciatus

“…Overexpression of P450 genes has been linked to the development of resistance in many insect species, including Musca domestica 5-10, Culex quinquefasciatus 11-13, Culex pipiens quinquefasciatus 14, Drosophila 15, 16, Aedes aegypti 17, Anopheles gambiae 18, Helicoverpa armigera 19, Tribolium castaneum 20, Bemisia tabaci 21, 22 , and Trialeurodes vaporariorum 23. In a recent study, Reid et al 24 used RNAseq methodology to conduct a whole transcriptome analysis of Culex quinquefasciatus in permethrin resistant mosquitoes and found that the overrepresented functional categories were mainly among the P450 genes, which may indicate that the overexpression of multiple P450 genes is a key factor governing the increased levels of detoxification of insecticides and insecticide resistance in Culex mosquitoes.…”

“…Nevertheless, the development of resistance to insecticides, especially to pyrethroids, in mosquito vectors has become a global problem 46-51. Our previous studies on whole transcriptome analyses of insecticide resistance 24 and genome analyses of cytochrome P450s and their expression profiles 12 in insecticide resistant mosquitoes have identified multiple up-regulated P450 genes in Cx. quinquefasciatus that may be responsible for the development of resistance to insecticides such as permethrin.…”

Venom allergen 5is Associated With Deltamethrin Resistance inCulex pipiens pallens(Diptera: Culicidae)

“…In addition, insecticides induce physiological changes in mosquitoes such as a thickening of the epidermis, which subsequently lowers their permeability to insecticides (Wood et al 2010). Studies investigating the mechanisms of pyrethroid resistance have identified other resistance-related genes, such as UDP-glycosyltransferases , Bozzolan et al 2014) and serine proteases (Reid et al 2012, Strachecka et al 2013.…”

Pyrethroid-resistance is modulated by miR-92a by targeting CpCPR4 in Culex pipiens pallens

“…Together with chitin, the cuticle serves as a barrier to the external environment (Papandreou et al 2010). In recent years, the rapid development of advanced biological technologies and transcriptomic and proteomic analyses of sensitive and resistant insects have revealed differential expression of ICPs, such as CPR, CPLC, and CPLCG subfamily members (Awolola et al 2009; Nkya et al 2014; Reid et al 2012; Silva et al 2012). In Anopheles gambiae , temporal and spatial differences in transcript abundance and protein localization mean that the structural cuticular proteins account for only about 2% of its protein coding genes.…”