Molecular Characterization and Differential Expression of Olfactory Genes in the Antennae of the Black Cutworm Moth Agrotis ipsilon

Abstract

Insects use their sensitive and selective olfactory system to detect outside chemical odorants, such as female sex pheromones and host plant volatiles. Several groups of olfactory proteins participate in the odorant detection process, including odorant binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors (ORs), ionotropic receptors (IRs) and sensory neuron membrane proteins (SNMPs). The identification and functional characterization of these olfactory proteins will enhance our knowledge of the molecular basis of insect chemoreception. In this study, we report the identification and differential expression profiles of these olfactory genes in the black cutworm moth Agrotis ipsilon. In total, 33 OBPs, 12 CSPs, 42 ORs, 24 IRs, 2 SNMPs and 1 gustatory receptor (GR) were annotated from the A. ipsilon antennal transcriptomes, and further RT-PCR and RT-qPCR revealed that 22 OBPs, 3 CSPs, 35 ORs, 14 IRs and the 2 SNMPs are uniquely or primarily expressed in the male and female antennae. Furthermore, one OBP (AipsOBP6) and one CSP (AipsCSP2) were exclusively expressed in the female sex pheromone gland. These antennae-enriched OBPs, CSPs, ORs, IRs and SNMPs were suggested to be responsible for pheromone and general odorant detection and thus could be meaningful target genes for us to study their biological functions in vivo and in vitro.

Identification and Expression Analysis of Putative Chemosensory Receptor Genes in Microplitis mediator by Antennal Transcriptome Screening

“…The ORs with antennal-specific or dominant expression profiles may play crucial roles in olfactory chemoreception of wasps. Similar to the present study, it was reported that some ORs could be expressed in a variety of tissues apart the olfactory organs 58-60. Our previous work also suggests a divergent expression profile of ORs in M. mediator 40.…”

Transcriptome profiling in the damselfly Ischnura elegans identifies genes with sex-biased expression

“…Because insects use olfaction for a variety of behaviours, including mate attraction, mate searching, oviposition site selection and the detection of host plant volatiles [44, 45], we looked specifically for olfactory genes in the assembled transcriptome. We identified several transcripts of odorant binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors (ORs) and ionotropic receptors (IRs) (Additional file 1: Sheet 15).…”

“…3). Olfactory receptors play an important role in sex pheromone and odour detection, and their up-regulation in male suggests an essential role in sex pheromone detection in females [45]. Ionotropic receptors are ancient chemosensory receptors and respond to different odorants [46].…”

Identification and expression analysis of an olfactory receptor gene family in green plant bug Apolygus lucorum (Meyer-Dür)

“…Results showed that AlucOR genes exhibited diverse expression patterns, which could be briefly classified into five types: antennal highly expressed ORs, head highly expressed ORs, abdomen highly expressed ORs, wing highly expressed ORs, and broadly expressed ORs (Supplementary Table 2). It was also reported that some ORs could be expressed in a variety of tissues apart from the olfactory organs3739. Antennae are important sensory organs for insect, so the majority of AlucOR genes displayed high expressions in antennae, including female and male antennal highly expressed genes.…”