Cloning and construction of plant expression vector of dihydroflavonol reductase gene (DFR) and transgenic Nicotiana tabacum.

The dihydroflavonol reductase(DFR) gene was cloned from young fruit of Medicago truncatula cv.5160 by RT-PCR and the coding sequences of this gene were analyzed.The result indicated that the full-length cDNA is 1 018 bp and contain open reading frame(ORF) encoding 337 amino-acids.The sequences were analyzed with software Blast and exhibited homologous 99.80% with DFR from GenBank.Then the promoter CaMV35S driven,plant expression vector pBIDFR with DFR was constructed based on the vector pBI121.By direct DNA transfer,pBIDFR was transferred into Agrobacterium tumefacien EHA105.Then transfer the new engineering bacterium to Nicotiana tabacum and six transgenic tobacco plants were obtained.