Abstract: Vacuolar-type H⁺-ATPase (V₁V₀-ATPase, V-ATPase), a type of proton pump, functions in almost every eukaryotic cell. In this study, a V-ATPase G subunit gene was cloned from Bactrocera dorsalis and named as BdorATPG. The open reading frame of BdorATPG is 354 bp in length, encoding 117 amino acid residues. Homology analysis showed that BdorATPG has high similarity with corresponding regions of V-ATPase G subunits from other dipteran insects, and shares 88.9% amino acid identity with the V-ATPase G subunit from Drosophila pseudoobscura. Three-dimensional structure modeling results showed that the N terminal (1-59 amino acids) sequence of BdorATPG is α-helix structure, and the hydrophilic and hydrophobic residues are almost symmetrically distributed on both sides of the helix. Real-time PCR analysis revealed that BdorATPG mRNA was expressed in all tissues, while the highest expression level was detected in the antenna. The BdorATPG mRNA level in male genital segments was about 6.04-fold as high as that in female genital segments, suggesting that V-ATPase plays an especially important role in male reproductive physiological processes.

Key words: Bactrocera dorsalis, V-ATPase G subunit, gene cloning, real-time PCR, tissue-specific expression