Identification of putative carboxylesterase and aldehyde oxidase genes from the antennae of the rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

In insects, odorant-degrading enzymes (ODEs) play essential roles in the degradation of volatile odorants and maintenance of olfactory sensitivity. ODEs include several enzyme families with detoxification functions, such as carboxylesterases (CXEs) and aldehyde oxidases (AOXs). The rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), is a serious rice insect pest in Asia. In this study, 18 putative CXE genes and four AOX genes were identified from the antennae of C. medinalis by retrieving a previously released transcriptome dataset. BLASTX searching and phylogenetic analyses showed that these genes are closely related to their respective orthologs in other lepidopteran species. Expression patterns of these genes were determined by reverse transcription-quantitative PCR (RT-qPCR). Four candidate genes, including three CmedCXEs (CmedCXE17, CmedCXE20 and CmedCXE24) and one CmedAOX (CmedAOX2) were antenna-enriched and considered potentially involved in odorant degradation. Our findings provide a comprehensive sequence resource and expression profiles of CXE and AOX genes in C. medinalis antennae, which may facilitate further studies of the odorant degradation mechanisms in this insect species.