Rdl allelic expression analysis in the western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chysomelidae)

The GABA receptor is the primary target of a number of insecticides, including cyclodienes. The loss of target site sensitivity to cyclodiene insecticides results from a substitution of alanine (A) to serine (S) or glycine (G),termed Rdl in many insect pests. In this report, we describe SNP analysis to analyze the Rdl allelic variation within three field populations of Diabrotica virgifera virgifera from PA, NE and IN with varying levels of resistance to aldrin, and a non-diapause strain, which is susceptible to aldrin. We compared genomic DNA and RNA sequences within the same individuals and found no correlation for the Rdl allele at the genomic DNA level with levels of susceptibility. However, there was a correlation between Rdl allele expression and the levels of resistance. These results may suggest a role of post-transcription regulation in the resistance.