Molecular identification and expression patterns of carboxylesterase genes based on transcriptome analysis of the common cutworm, Spodoptera litura (Lepidoptera: Noctuidae)

•We first identified 24 SlitCXEs of S. litura.•Some genes displayed antennae- or PG-predominant expression.•Some genes could be as potential targets to develop pollution-free pesticides against S. litura.

Carboxylesterases (CXEs) belong to a family of metabolic enzymes that are widely distributed in insects and other organisms and can rapidly degrade the components of sex pheromones and plant volatiles with an acetate functional group. The common cutworm, Spodoptera litura, is an important agricultural pest around the world, causing vast economic losses every year. The female sex pheromones of S. litura comprise four acetates, Z9, E11-14:OAc; Z9, E12-14:OAc; Z9-14:OAc; and E11-14:OAc, but the degradation mechanisms of these components are not well understood. By analysing previously obtained transcriptomic data of the sex pheromone glands, we identified a total of 24 putative CXE genes in S. litura. Gene expression patterns and phylogenetic analysis revealed 5 genes with antennae-specific or biased expression, and clustered with genes showed involvement in the degradation of sex pheromones or other detoxification in other insects. SlitCXE10 was expressed specifically in the antennae of both sexes, and SlitCXE14, 17, 19, and 21 had high antenna biased expression. Interestingly, RT-PCR and qPCR tests indicated that SlitCXE24 had significantly higher expression in PG than in other tissue, and that it could be a potential candidate gene for sex pheromone degradation in PG. This study is the first to provide solid background information for the further elucidation of sex pheromone degradation, and ultimately provides potential targets for the disruption of sexual communication in S. litura for new pest management.

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