Transcriptome profiling of pyrethroid resistant and susceptible mosquitoes in the malaria vector, Anopheles sinensis

Abstract

BackgroundAnopheles sinensis is a major malaria vector in China and other Southeast Asian countries, and it is becoming increasingly resistant to the insecticides used for agriculture, net impregnation, and indoor residual spray. Very limited genomic information on this species is available, which has hindered the development of new tools for resistance surveillance and vector control. We used the 454 GS FLX system and generated expressed sequence tag (EST) databases of various life stages of An. sinensis, and we determined the transcriptional differences between deltamethrin resistant and susceptible mosquitoes.ResultsThe 454 GS FLX transcriptome sequencing yielded a total of 624,559 reads (average length of 290 bp) with the pooled An. sinensis mosquitoes across various development stages. The de novo assembly generated 33,411 contigs with average length of 493 bp. A total of 8,057 ESTs were generated with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation. A total of 2,131 ESTs were differentially expressed between deltamethrin resistant and susceptible mosquitoes collected from the same field site in Jiangsu, China. Among these differentially expressed ESTs, a total of 294 pathways were mapped to the KEGG database, with the predominant ESTs belonging to metabolic pathways. Furthermore, a total of 2,408 microsatellites and 15,496 single nucleotide polymorphisms (SNPs) were identified.ConclusionsThe annotated EST and transcriptome databases provide a valuable genomic resource for further genetic studies of this important malaria vector species. The differentially expressed ESTs associated with insecticide resistance identified in this study lay an important foundation for further functional analysis. The identified microsatellite and SNP markers will provide useful tools for future population genetic and comparative genomic analyses of malaria vectors.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-448) contains supplementary material, which is available to authorized users.

Comparative transcriptome analyses of deltamethrin-susceptible and -resistant Culex pipiens pallens by RNA-seq

“…quinquefasciatus . We used the premixed samples of different developmental stages to increase the transcript coverage (Zhu et al 2014), and to provide the most comprehensive Cx. pipiens pallens transcriptome database for subsequent analyses.…”

“…As mentioned before, researchers have identified massive pyrethroid resistance-related DEGs by the transcriptome sequencing of other mosquito species. By comparison, many of the DEGs belong to the same gene families, such as P450s, cuticle proteins, UDP-glucuronosyltransferases, lipases, serine proteases, heat shock proteins and others (Bonizzoni et al 2012; David et al 2014; Reid et al 2012; Zhu et al 2014). …”

“…To distinguish resistant from susceptible strains, non-blood-fed adult females were exposed to 0.05% deltamethrin-impregnated drug membranes by the standard WHO susceptibility tube bioassay (WHO 2013). The mosquitoes that knocked down after one-hour exposure were classified as deltamethrin susceptible, and those survived after the 24-hour recovery period were classified as deltamethrin resistant (Bonizzoni et al 2012; Zhu et al 2014). The knocked-down mosquitoes were immediately preserved in Eppendorf tubes after one-hour exposure to avoid the RNA degradation in the following 24-hour recovery period.…”

“…Several researchers have used transcriptome sequencing to study pyrethroid resistance in mosquitoes, including Anopheles gambiae (Bonizzoni et al 2012), Anopheles sinensis (Zhu et al 2014), Aedes aegypti (David et al 2014), and Culex quinquefasciatus (Reid et al 2012). However, the mosquitoes from different genetic background evolve different mechanisms of resistance to pyrethroids (Bonizzoni et al 2012; Zhong 2011).…”

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

“…The mosquitoes that survived the 24-h recovery period were classified as deltamethrin resistant, while those knocked down early during the bioassay were classified as deltamethrin susceptible. The knocked-down mosquitoes were immediately preserved in Eppendorf tubes without allowing a 24-h recovery period to prevent postmortem RNA degradation (Bonizzoni et al 2012, Zhu et al 2014.…”