Leptinotarsa decemlineata Transcriptome

The Colorado potato beetle (CPB), Leptinotarsa decemlineata, is a significant pest of potato, and its impact on agriculture is measured on a global scale. The beetle is mainly controlled by neonicotinoid insecticides such as imidacloprid, however, resistance development is a growing concern. In this study, we investigated the molecular mechanisms of imidacloprid resistance in CPB. We compared the transcriptome profiles of imidacloprid resistant and sensitive beetle strains using mRNA sequencing and identified a total of 7572 differentially expressed contigs between the two strains. Of these, 4220 were up-regulated and 3352 were down-regulated in the resistant strain. Differentially expressed contigs were then manually screened to identify transcripts encoding detoxifying enzymes (cytochrome P450s (CYPs), esterases, glutathione S-transferases (GSTs), UDP-glycosyltransferases (UGTs)) and ATP-binding cassette (ABC) transporters whose overexpression is often associated with insecticide resistance. A total of 102 contigs corresponding to genes of interest were identified; of these 74 showed increased while 28 showed decreased, transcript levels in the resistant strain. Of the 74 up-regulated contigs, 24 corresponded to CYP, 13 to UGT, 14 to esterase, 15 to GST, and 8 to ABC transporter encoding transcripts. Whereas, among the 28 down-regulated contigs, there were 6 CYP, 2 UGT, 9 esterase, 4 GST, and 7 ABC transporter encoding transcripts.