Transcriptomics of the Bed Bug (Cimex lectularius)

Abstract

BackgroundBed bugs (Cimex lectularius) are blood-feeding insects poised to become one of the major pests in households throughout the United States. Resistance of C. lectularius to insecticides/pesticides is one factor thought to be involved in its sudden resurgence. Despite its high-impact status, scant knowledge exists at the genomic level for C. lectularius. Hence, we subjected the C. lectularius transcriptome to 454 pyrosequencing in order to identify potential genes involved in pesticide resistance.Methodology and Principal FindingsUsing 454 pyrosequencing, we obtained a total of 216,419 reads with 79,596,412 bp, which were assembled into 35,646 expressed sequence tags (3902 contigs and 31744 singletons). Nearly 85.9% of the C. lectularius sequences showed similarity to insect sequences, but 44.8% of the deduced proteins of C. lectularius did not show similarity with sequences in the GenBank non-redundant database. KEGG analysis revealed putative members of several detoxification pathways involved in pesticide resistance. Lamprin domains, Protein Kinase domains, Protein Tyrosine Kinase domains and cytochrome P450 domains were among the top Pfam domains predicted for the C. lectularius sequences. An initial assessment of putative defense genes, including a cytochrome P450 and a glutathione-S-transferase (GST), revealed high transcript levels for the cytochrome P450 (CYP9) in pesticide-exposed versus pesticide-susceptible C. lectularius populations. A significant number of single nucleotide polymorphisms (296) and microsatellite loci (370) were predicted in the C. lectularius sequences. Furthermore, 59 putative sequences of Wolbachia were retrieved from the database.ConclusionsTo our knowledge this is the first study to elucidate the genetic makeup of C. lectularius. This pyrosequencing effort provides clues to the identification of potential detoxification genes involved in pesticide resistance of C. lectularius and lays the foundation for future functional genomics studies.

The transcriptome of Spodoptera exigua larvae exposed to different types of microbes

“…Genes involved in the different mechanisms are relatively well characterized in the model organism Drosophila melanogaster, although very little is known for nonmodel organisms. Only recently, because of the generalization of the NGS technologies, are pathogen-related genes being identified in non-model insects (Pauchet et al, 2009;Mittapalli et al, 2010;Bai et al, 2011).…”

Transcriptome analysis of the salivary glands of potato leafhopper, Empoasca fabae

“…Roche Ò 454 pyrosequencing has in the recent past revolutionized functional genomic studies in non-model organisms, particularly in insects wherein little to no genetic information is available (Francischetti et al, 2007;Morozova and Marra, 2008;Margulies et al, 2005;Vera et al, 2008;Pauchet et al, 2009;Mittapalli et al, 2010;Bai et al, 2011). The developed transcriptomic database can subsequently be used as a reference for future functional studies like RNA seq and to mine for candidate targets for RNAi experiments.…”

Survival and Fecundity of Two Strains ofCimex lectularius(Hemiptera: Heteroptera)

“…There is an emerging thread of research examining bed bug demography (Polanco et al 2011a). Currently, the Harlan strain is used as the standard insecticide-susceptible strain in bed bug research across the United States (Zhu et al 2010, Adelman et al 2011, Bai et al 2011. Basic life table parameters evaluating the life expectancy of Harlan bed bugs fed on a regular basis have not been reported since 1973, when the Harlan strain was initiated.…”