Identification and expression profile analysis of odorant-binding protein genes in Apolygus lucorum (Hemiptera: Miridae)

Insect odorant-binding proteins (OBPs) are one group of olfactory-related proteins and are believed to play essential roles in the physiological activity of insects. In this study, we constructed a cDNA library from the antennae of Apolygus lucorum (Meyer-Dur). Twelve novel putative OBP genes were identified from the antennal cDNA library, and the expression profiles of the 12 OBPs in different tissues (antennae, heads, thoraxes, abdomens, legs and wings) were analyzed by real-time quantitative PCR. The results revealed that AlucOBP2, AlucOBP7, AlucOBP8, AlucOBP11 and AlucOBP12 are highly expressed in antennae. Especially the transcript levels of AlucOBP7, AlucOBP8 and AlucOBP11 in male antennae were significantly higher than in female antennae, suggesting their potential olfactory functions in host seeking and mate finding of A. lucorum. However, AlucOBP1, AlucOBP5 and AlucOBP6 were highly expressed in the heads, whereas AlucOBP3 was specifically expressed only in the legs. In addition, AlucOBP4, AlucOBP9 and AlucOBP10 were expressed in almost all chemosensory tissues (antennae, heads, wings and legs). Our research is meaningful for understanding the molecular basis of the insect chemoreception requirements and provides valuable target genes to control the insect pests.