Cloning and Expression Analysis of AzanOBP7, a Minus-C Odorant-Binding Protein Gene, from Agrilus zanthoxylumi (Coleoptera: Buprestidae)

Odorant-binding proteins (OBPs) play an important role in specific recognition, binding, and transportation of odorants. In this study, the full-length complementary DNA (cDNA) sequence of AzanOBP7, a Minus-C OBP gene, from Agrilus zanthoxylumi Li Ming Lou (Coleoptera: Buprestidae) was cloned by rapid amplification of cDNA ends based on transcriptome data. The bioinformatic analysis showed that AzanOBP7 contains a 450-bp open reading frame encoding a 149-residue polypeptide, with a molecular mass of 17.176 kDa. It was predicted to be a nontransmembrane protein with an 18-amino acid signal peptide at the N terminus. The predicted three-dimensional structure of AzanOBP7 by AphadFold2 possesses seven a helices and two disulfide bridges. The multiple sequence alignment and phylogenetic tree revealed that AzanOBP7 reached the highest identity (94.70%) with Agrilus mali Matsumura (Coleoptera: Buprestidae) AmalOBP11; they also were closely aligned in a clade. Quantitative real-time polymerase chain reaction showed that AzanOBP7 exhibited the highest expression level in the abdomen of adult females. In the thorax, the expression level in adult males was significantly higher than that in other aged males (P, 0.01). Our study offers a theoretical foundation for further study on the functional characteristics of A. zanthoxylumi OBPs.