Molecular Characterization of Odorant Receptor Gene GmolOR7 in Grapholita molesta (Lepidoptera: Tortricidae)

Abstract Grapholita molesta Busck (Lepidoptera: Tortricidae) is a major fruit pest of a wide range of Rosaceae trees. Olfaction plays a crucial role in insect behavioral activities, and insects primarily rely on odorant receptors (ORs) to detect odorant molecules. Several olfactory-related genes in G. molesta have been studied; however, the ORs of G. molesta are unclear. Here, GmolOR7, a general OR gene, was cloned and characterized. Sequence alignment and phylogenetic tree analysis showed that GmolOR7 is closely related to Cydia pomonella OR54, with the amino acid sequence identity of 80.21%. Furthermore, the different developmental stages and tissues of GmolOR7 in G. molesta were analyzed by real-time quantitative polymerase chain reaction. The results demonstrated that GmolOR7 was expressed at higher levels in adults, and particularly in the antennae of females. GmolOR7 expression was the highest in 3-d-old adults. These results will provide an indication for further functional study of the GmolOR7 in G. molesta and its role in the detection of host-plant volatiles by insects in general.