Abstract:To research the function of tobacco orf25 gene as well as the correlation between the orf25 gene and tobacco male sterility, the flower specific promoter PchsA was amplified from plasmid PUC57-PchsA by PCR, and replaced constitutive promoter CaMV35S in plant expression vector pBI121. Then, the orf25 gene was inserted into the downstream of PchsA to construct the plant expression vector driven by flower specific promoter PchsA. The sequencing results showed that plant expression vector pBI121-PchsA-orf25 was constructed successfully. After transferred into Agrobacterium tumefaciens LBA4404, it was used to transform the male sterile tobacco MS Gexin 3. 76 transgenic tobacco plants were obtained, of which 18 was proved to be transgenic positive by PCR, the transformation frequency was 23.7%. The results indicated that the target gene orf25 had been integrated into tobacco genome, which lays a foundation for the further study of the gene function and its relationship with tobacco male sterility.