Identification and Expression Profile of Chemosensory Receptor Genes in Aromia bungii (Faldermann) Antennal Transcriptome

SIMPLE SUMMARY: There are many chemosensory receptor genes involved in insect chemodetection, including odorant receptors (ORs), gustatory receptors (GRs) and ionotropic receptors (IRs). In contrast to the well-studied Lepidoptera chemosensory receptor genes, the molecular mechanisms of olfactory sensing in Coleoptera are much less understood. The olfactory system plays a crucial role in insect survival. Understanding the olfactory mechanism of insects in depth might provide theoretical guidance for the development of effective pest control measures. The red-necked longicorn beetle, Aromia bungii (Faldermann) (Coleoptera: Cerambycidae), is a wood-boring pest. In order to increase our understanding of the chemosensory receptor genes of the beetle, we first analyzed the transcriptome data of adult A. bungii antennae using bioinformatics, followed by the screening and identification of chemosensory receptor genes. Then, the expression of the chemosensory receptor genes of both male and female adults was examined using qRT-PCR. These findings will provide valuable information for the analysis of the role of chemosensory receptor genes in A. bungii. ABSTRACT: The red-necked longicorn beetle, Aromia bungii (Faldermann) (Coleoptera: Cerambycidae), is a major destructive, wood-boring pest, which is widespread throughout the world. The sex pheromone of A. bungii was reported earlier; however, the chemosensory mechanism of the beetle remains almost unknown. In this study, 45 AbunORs, 6 AbunGRs and 2 AbunIRs were identified among 42,197 unigenes derived from the antennal transcriptome bioinformatic analysis of A. bungii adults. The sequence of putative Orco (AbunOR25) found in this study is highly conserved with the known Orcos from other Coleoptera species, and these Orco genes might be potentially used as target genes for the future development of novel and effective control strategies. Tissue expression analysis showed that 29 AbunOR genes were highly expressed in antennae, especially in the antennae of females, which was consistent with the idea that females might express more pheromone receptors for sensing pheromones, especially the sex pheromones produced by males. AbunOR5, 29, 31 and 37 were clustered with the pheromone receptors of the cerambycid Megacyllene caryae, suggesting that they might be putative pheromone receptors of A. bungii. All six AbunGRs were highly expressed in the mouthparts, indicating that these GRs may be involved in the taste perception process. Both AbunIRs were shown to be female-mouthparts-biased, suggesting that they might also be related to the tasting processes. Our study provides some basic information towards a deeper understanding of the chemosensing mechanism of A. bungii at a molecular level.