Three oligosaccharides (EOS, WOS and SOS) were respectively prepared from the corresponding
polysaccharides, namely exopolysaccharide (EPS), water-extracted mycelial polysaccharide (WPS) and sodium
hydroxide-extracted mycelial polysaccharides (SPS) from the endophytic fungus Fusarium oxysporum
this study, the effects of EOS,WOS and SOS on the activities of the defense-related enzymes, namely phenylalanine
ammonia lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD) in its host plant Dioscorea zingiberensis
cultures were investigated.
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 themaximumvalues by 0.25 mg/mL ofWOS at 48 h after treatment,whichwere 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 theirmaximum values treatedwith
2.5 mg/mL ofWOS at 48 h after treatment, whichwere 4.61 and 4.19-fold as those of control, separately.
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.
Dzf17 may be related to the activation and enhancement of the defensivemechanisms of D. zingiberensis
suspension cell and seedling cultures.