Targeted RNA sequencing reveals differential patterns of transcript expression in geographically discrete, insecticide resistant populations of Leptinotarsa decemlineata.

BACKGROUND The Colorado potato beetle (Leptinotarsa decemlineata Say) is a major agricultural pest of commercial potatoes, partially due to its ability to rapidly develop resistance to multiple insecticide modes of action. Patterns of L. decemlineata insecticide resistance in the contiguous United States have been linked to geographic location and regional management practices. Several previous studies have classified enzymes which are over-expressed following L. decemlineata exposure to commercial pesticides, many of which have been linked to xenobiotic metabolism. Studies have further associated geographic disparities in resistance patterns to cross-resistance driven by fungicide exposure in the East Coast and Midwest. RESULTS In this study, our objective was to investigate transcript expression of 38 previously classified detoxification enzymes induced by imidacloprid (an insecticide) and chlorothalonil (a fungicide) within 5 discrete populations of L. decemlineata obtained from areas in the U.S. representing eastern, midwestern and western production regions. We found unique patterns of transcript expression in different geographic locations, including overexpression of transcripts related to insecticide metabolism within insecticide resistant populations. CONCLUSION The results suggest the genetic response of these populations may be partially linked to geographic location and corresponding management practices. This article is protected by copyright. All rights reserved.