Knockdown of the GABA receptor RDL genes decreases abamectin susceptibility in the rice stem borer, Chilo suppressalis.

Abstract The γ-aminobutyric acid (GABA) receptor is a primary neurotransmitter receptor in both vertebrate and invertebrate nervous systems. Multiple RDL subunits have been found in insects including the rice stem borer, Chilo suppressalis , however, comparative characterization of duplicated RDL genes in insects is still limited. In this study, comparison of the genomic sequences and the cDNA sequences revealed that both CsRDL1 and CsRDL2 consisted of 10 exons and 9 introns, and their exon-intron boundaries occur in the same position with respect to the coding sequences. Expression profiling showed that both CsRDL1 and CsRDL2 were predominantly expressed in nervous system, and had low expression levels in the gut and integument. The transcript level of CsRDL2 dramatically increased from the prepupae to late pupae and were much higher than that of CsRDL1 in adult stages. Notably, dietary ingestion of dsRDL1 and dsRDL2 significantly decreased the larval susceptibility to abamectin. These results suggest that CsRDL1 and CsRDL2 might play both physiological roles in development and toxicological roles in action of abamectin in C. suppressalis. Graphical abstract Unlabelled Image Highlights • The genomic sequences of CsRDL1 and CsRDL2 were compared. • CsRDL1 and CsRDL2 were predominantly expressed in nervous system. • The transcript level of CsRDL2 dramatically increased from the prepupae to late pupae. • Knockdown of dsRDL1 and dsRDL2 significantly decreased the larval susceptibility to abamectin. [ABSTRACT FROM AUTHOR]