Abstract: Three oligosaccharides (EOS,WOS and SOS) were prepared from their corresponding polysaccharides (EPS,WPS and SPS) of Berkleasmium sp.Dzf12,an endophytic fungal strain of Dioscorea zingiberensis. The effects of oligosaccharides on the activities of defense-related enzymes phenylalanine ammonia lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD) in suspension cell and seedling cultures of D.zingiberensis were investigated.For the suspension cell cultures,the highest activities of PAL and PPO were induced by 0.25 mg/mL of EOS at 24 h after treatment,which were 6.19 and 7.16- fold of control, respectively. While the POD activity was increased to the maximum by 0.05 mg/mL of EOS at 48 h after treatment,which was 4.63-fold of control.For the seedling cultures,the highest activities of PAL,PPO and POD were induced by 2.5 mg/mL of EOS at 48,24 and 48 h,respectively,which were 6.21-, 4.80- and 6.09-fold of control, separately. Among three oligosaccharides,EOS was the most effective elicitor to induce activities of defense-related enzymes in D.zingiberensis cultures.The results demonstrated that the increased activities of PAL,PPO and POD elicited by the oligosaccharides may be related to the activation of defensive mechanisms of D.zingiberensis suspension cell and seedling cultures.

Key words: oligosaccharides;endophytic fungus, Berkleasmium sp.Dzf12;Dioscorea zingiberensis;defense-related enzymes;cultures