Transcriptome Analysis of the Triatoma infestans (Hemiptera: Reduviidae) Integument

Abstract

The insect integument, formed by the cuticle and the underlying epidermis, is essential for insect fitness, regulation of lipid biosynthesis and storage, insect growth and feeding, together with development progress. Its participation in insecticide resistance has also been outlined. Triatoma infestans Klug is one of the major vectors of Chagas disease in South America; however, genomic data is scarce. In this study, we performed a transcriptome analysis of the nymph integument in order to identify which genes are expressed and their putative role. Using the 454 GS-FLX sequencing platform, we obtained approximately 144620 reads from the integument tissue. These reads were assembled into 6495 isotigs and 8504 singletons. Based on BLAST similarity searches, about 8000 transcripts were annotated with known genes, conserved domains, and/or Gene Ontology (GO) terms. The most abundant transcripts corresponded to transcription factors and nucleic acid metabolism, membrane receptors, cell signaling, and proteins related to cytoskeleton, transport and cell energy processes, among others. More than 10% of the transcripts encoded proteins putatively involved in the metabolism of fatty acids and related components (fatty acid synthases, elongases, desaturases, fatty alcohol reductases), structural integument proteins, and the insecticide detoxification system (among them, cytochrome P450s, esterases and glutathione transferases). Real time qPCR assays were used to investigate their putative participation in the resistance mechanism. This preliminary study is the first transcriptome analysis of a triatomine integument, and together with prior biochemical information, will help further understand the role of the integument in a wide array of mechanisms