Molecular cloning, genomic structure, and genetic mapping of two Rdl-orthologous genes of GABA receptors in the diamondback moth, Plutella xylostella

摘要

The Resistance to dieldrin (Rdl) gene encodes a subunit of the insect -aminobutyric acid (GABA) receptor. Cyclodiene resistance in many insects is associated with replacement of a single amino acid (alanine at position 302) with either a serine or a glycine in the Rdl gene. Two Rdl-orthologous genes of GABA receptors (PxGABAR1 and PxGABAR2) were cloned and sequenced from a susceptible strain (Roth) of Plutella xylostella. PxGABAR1 and PxGABAR2 showed 84% and 77% identity with the Rdl gene of Drosophila melanogaster at an amino acid level, respectively. The coding regions of PxGABAR1 and PxGABAR2 both comprise ten exons, with two alternative RNA-splicing forms in exon 3 of both genes. At the orthologous position of alanine-302 in D. melanogaster Rdl, PxGABAR1 has a conserved alanine at position 282. PxGABAR2 has a serine instead of an alanine at the equivalent position. With two informative DNA markers, both PxGABAR1 and PxGABAR2 were mapped onto the Z chromosome of P. xylostella. © 2010 Wiley Periodicals, Inc.