Genome-Wide Identification and Stage-Dependent Analysis of Odorant-Binding Protein and Chemosensory Protein Genes in the Summer Fruit Tortrix Moth, Adoxophyes orana (Lepidoptera: Tortricidae)

Abstract

The summer tortrix fruit moth, Adoxophyes orana, is a major fruit trees pest in Asia and Europe, which rolls leaves for food and generate silk nets to avoid prey by natural enemies. As a polyphagous species whose host plants cover more than 30 species, it relies on the olfactory system to receive odor molecules for feeding and mating. However, the gene resources of olfactory genes remain limited. In this study, we conducted genome-guided RNA-seq analyses and identified 31 putative OBP genes (24 classical, 4 minus-C and 3 plus-C OBPs, 4 PBPs, and 2 GOBPs) and 21 putative CSP genes. These putative OBPs were located in 8 chromosomes, with 11 in Chr15 and 6 in Chr16. Two GOBPs and four PBPs are adjacently located in Chr16, and 18 out of 21 CSPs are concentrated in Chr16. Phylogenetic analyses showed that all the putative OBPs were classified into five clusters, with all GOBPs and PBPs exclusively in cluster III, and all four minus-C OBPs in cluster IV. Expression analyses indicated that putative AoraOBP7/10 were highly expressed throughout larval stages, putative AoraOBP5/6/8/12/15/21/25 were abundant in first-instar larvae, and 18 of 31 putative OBPs were mainly expressed in adults. In addition to rich AoraOBPs in adult antennae, AoraOBP18/19/20/22 were surprisingly highly expressed in male abdomens, and putative AoraCSPs showed complex expression patterns when combining RNA-seq analyses and RT-qPCR analyses. These results provide a gene resource for future functional studies of OBPs and CSPs, which potentially act as targets for pest management.