Abstract: Three polysaccharides,namely exopolysaccharide (EPS),water-extracted mycelial polysaccharide (WPS) and sodium hydroxide-extracted mycelial polysaccharide (SPS) prepared from the endophytic fungus Fusarium oxysporum Dzf17,were studied for their enhancing effects on diosgenin production in Dioscorea zingiberensis seedling and cell cultures.Among them,WPS showed the most significant enhancing effect on diosgenin accumulation in D.zingiberensis seedling and cell cultures.When D.zingiberensis seedling and cell cultures were separately treated with WPS at 20 mg/L,diosgenin yields were dramatically increased to 10.04 mg/L and 2.40 mg/L,which were 3.11 and 3.87 times to those (3.23 mg/L and 0.62 mg/L) of control,respectively.These results indicated that addition of the polysaccharides from the endophytic fungus F.oxysporum Dzf17 was an effective way for enhancing production of diosgenin in D.zingiberensis cultures.

Key words: Dioscorea zingiberensis, diosgenin, endophytic fungus, Fusarium oxysporum Dzf17, polysaccharide, cell cultures, seedling cultures