Abstract: 【Aim】 This study aims to clarify the expression pattern of odorant binding protein 1 (OBP1) in Aethina tumida and analyze the role of AtOBP1 in olfactory recognition of A. tumida.【Methods】 The cDNA full-length sequence of AtOBP1 was cloned based on the transcriptome and genome database of A. tumida and analyzed by bioinformatics. RT-qPCR was used to detect the expression levels of AtOBP1 in different developmental stages (egg, larva, pupa, female adult and male adult), different tissues (head, cuticle, wing, leg, fat body, gut, Malpighian tubules, testis and ovary) of the 7-day-old adult and in the head of different day-old adults of A. tumida after eclosion. The biological function of AtOBP1 in olfactory recognition of A. tumida was studied by RNA interference (RNAi) and Y-tube behavior choice experiment. 【Results】The cDNA full-length sequence of AtOBP1 gene (GenBank accession no.: MT211982.1) has six exons and an open reading frame (ORF) of 447 bp in length. AtOBP1 encodes 148 amino acid residues with PBP_GOBP superfamily conserved domain, and the predicted molecular mass and isoelectric point are 15.9 kD and 4.73, respectively. AtOBP1 protein is a dimer composed of six α-helics with six conserved cysteines that form three disulfide bonds. The phylogenetic tree also showed that AtOBP1 was closely clustered into one branch with TmOBP8 from Tenebrio molitor of Coleoptera. The RT-qPCR results showed that AtOBP1 was highly expressed in the pupal stage and the male adult stage, and was highly specifically expressed in the head and testis of adults. In addition, the expression level of AtOBP1 in adult head increased gradually with the day-old age, reached two peaks in the 5- and 7-day-old adult stages, respectively, and decreased in the 8-day-old adult stage. RNAi in combination with Y-tube behavior choice experiment results revealed that silencing of AtOBP1 resulted in significantly reduced preference of A. tumida adults to the pollen volatile compounds ethyl palmitate and ethyl linolenate.【Conclusion】AtOBP1 belongs to Classical OBPs family. AtOBP1 is mainly expressed in the head and testis of A. tumida adults, and may participate in the recognition process of the pollen volatile compounds ethyl palmitate and ethyl linolenate in A. tumida.
Key words: Aethina tumida; odorant binding protein; AtOBP1; RNAi; olfactory behavior