Antennal transcriptome analysis and expression profiles of odorant binding proteins in Eogystia hippophaecolus (Lepidoptera: Cossidae).

BACKGROUND: Eogystia hippophaecolus (Hua et al.) (Lepidoptera: Cossidae) is the major threat to seabuckthorn plantations in China. Specific and highly efficient artificial sex pheromone traps was developed and used to control it. However, the molecular basis for the pheromone recognition is not known. So we established the antennal transcriptome of E. hippophaecolus and characterized the expression profiles of odorant binding proteins. These results establish and improve the basis knowledge of the olfactory receptive system, furthermore provide a theoretical basis for the development of new pest control method.

RESULTS: We identified 29 transcripts encoding putative odorant-binding proteins (OBPs), 18 putative chemosensory proteins (CSPs), 63 odorant receptors (ORs), 13 gustatory receptors (GRs), 12 ionotropic receptors (IRs), and two sensory neuron membrane proteins (SNMPs). Based on phylogenetic analysis, we found one Orco and three pheromone receptors of E. hippophaecolus and found that EhipGR13 detects sugar, EhipGR11 and EhipGR3 detect bitter. Nine OBPs expression profile indicated that most were the highest expression in antennae, consistent with functions of OBPs in binding and transporting odors during the antennal recognition process. OBP6 was external expressed in male genital-biased in, and this locus may be responsible for pheromone binding and recognition as well as mating. OBP1 was the highest and biased expressed in the foot and may function as identification of host plant volatiles.

CONCLUSIONS: One hundred thirty-seven chemosensory proteins were identified and the accurate functions and groups of part proteins were obtained by phylogenetic analysis. The most OBPs were antenna-biased expressed, which are involved in antennal recognition. However, few OBP was detected biased expression in the foot and external genitalia, and these loci may function in pheromone recognition, mating, and the recognition of plant volatiles.