Identification and tissue distribution of odorant binding protein genes in the citrus fruit fly, Bactrocera minax (Enderlein) (Diptera: Tephritidae)

Bactrocera minax is a destructive citrus pest in China. Owing to the increasing demand for diminishing pesticide applications in orchards, novel and effective control strategies are urgently needed. Odorant binding proteins (OBPs) represent potential targets that can facilitate the creation of environmentally friendly alternatives to the chemical control strategies. However, very little is known concerning OBP genes in B. minax. Here, we obtained seven novel OBP genes (BminOBP1-BminOBP7) from B. minax through a transcriptome analysis. All of them belong to classic OBPs. Subsequently, a phylogenetic tree was generated to characterize the seven OBP genes. Moreover, the tissue expression profiles of these OBP genes were determined by the real-time PCR. The results showed that three OBP genes (BminOBP3, BminOBP6 and BminOBP5) were highly expressed in antennae. The BminOBP3 and BminOBP6 were expressed primarily in antennae. BminOBP3 was male antenna-biased while BminOBP6 was female antenna-biased. The BminOBP5 showed high expression not only in antennae but also in legs. The other four OBP genes were highly expressed in non-olfactory tissues including heads, legs, wings and abdomens. Based on these results, the possible functions of BminOBPs are discussed. The present study provides bases for functional study of these OBPs in B. minax.