BACKGROUND: 10-Deacetylbaccatin III (10-DAB) and baccatin III are intermediates in the biosynthesis of Taxol (an anticancer drug) and useful precursors for semi-synthesis of the drug. In this study, a bioconversion system was established for the production of baccatin III, an advanced precursor of paclitaxel, in the transgenic mushroom Flammulina velutipes expressing the 10-deacetylbaccatin III-10 beta-O-acetyltransferase gene. The expression vector pgFvs-TcDBAT containing the 10-deacetylbaccatin III-10 beta-O-acetyltransferase (DBAT) gene was constructed and transformed into the cells of F. velutipes by polyethylene glycol-mediated protoplast transformation. RESULTS: Polymerase chain reaction and Southern blotting analysis verified the successful integration of the exogenous DBAT gene into the genome of F. velutipes. Reverse transcription polymerase chain reaction and enzyme activity analyses confirmed that the DBAT gene was expressed in F. velutipes, and DBAT is able to convert substrate into baccatin III. CONCLUSION: The DBAT gene from the plant Taxus chinensis can be functionally expressed in F. velutipes. Transgenic F. velutipes expressing the DBAT gene is able to produce the target product, baccatin III. This is the first report about the transformation and expression of paclitaxel biosynthetic gene in the edible mushroom F. velutipes. This represents a significant step towards bio-production of paclitaxel and its advanced precursor baccatin III in an edible fungus. (C) 2014 Society of Chemical Industry