Effects of oligosaccharides from endophytic Fusarium oxysporum Dzf17 on activities of defense-related enzymes in Diosocrea zingiberensis suspension cell and seedling cultures
Abstract
Backgroud: Three oligosaccharides (EOS, WOS and SOS) were respectively prepared by acid hydrolysis of their corresponding polysaccharides, namely exopolysaccharide (EPS), water-extracted mycelial polysaccharide (WPS) and sodium hydroxide-extracted mycelial polysaccharides (SPS) from the endophytic fungus Fusarium oxysporum Dzf17. In the present study, the effects of the oligosaccharides EOS, WOS and SOS on activities of the defense-related enzymes, namely phenylalanine ammonia lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD) in its host plant Dioscorea zingiberensis suspension cell and seedling cultures were investigated.
Results: For the suspension cell cultures of D. zingiberensis, the highest PAL activity was induced by 0.5 mg/mL of WOS at 48 h after treatment, which was 4.55-fold as that of control. Both PPO and POD activities were increased to the maximum values by 0.25 mg/mL of WOS at 48h after treatment, which were respectively 3.74 and 3.45-fold as those of control. For the seedling cultures, the highest PAL activity was elicited by 2.5 mg/mL of EOS at 48 h after treatment, which was 3.62-fold as that of control. Both PPO and POD reached their maximum values treated with 2.5 mg/mL of WOS at 48 h after treatment, which were 4.61 and 4.19-fold as those of control, separately.
Conclusions: Among three oligosaccharides, both EOS and WOS significantly increased the activities of PAL, PPO and POD in the suspension cell and seedling cultures of D. zingiberensis. The results suggested that the oligosaccharides from the endophytic fungus F. oxysporum Dzf17 may be related to activation and enhancement of the defensive mechanisms of D. zingiberensis suspension cell and seedling cultures. By investigating the effects of oligosaccharide elicitors from plant endophyte on the defensive system of its host plant, it will provide more information for further understanding the interactions between endophytic F. oxysporum Dzf17 and its host D. zingiberensis.