In order to improve the yield of resveratrol from Polygonum cuspidatum through endophytic fungi transformation, endophytic fungal strains capable of transforming polydatin from Polygonum cuspidatum were screened. The contents of resveratrol and polydatin were determined by high performance liquid chromatography (HPLC). The results indicated that 6 endophytic fungal strains capable of transforming polydatin from Polygonum cuspidatum were identified. Strain J1 had the highest transformation rate, 25.6%. The strain J1 was identified as Penicilli...