Isolation And Partial Purification Of Oligosaccharides From Cultured Fungal Cells And Functional Study On The Oligosaccharide Inducing Resistance In Plants

Oligosaccharides derived from fungal DL603 were isolated and purified, and the functional role of which inducing resistance in plants was examined to illuminate the mechanism of signal transduction. The fungal DL603 was degraded by hydrolytic enzyme 0603. The hydrolysis reaction was conducted, and ion exchange and gel filtration chromatography were exploited for purifying the products. High performance anion exchange chromatography (HPAEC) analysis showed that the oligosaccharides have been isolated with certain degree of polymerization, and the highest active fractions consists of glueosamine, galactose, glucose and mannose. To determine if functional oligosaccharides have affinity to the plasma membrane, cotton cotyledon homogenate was incubated with fluorescence-labeled active oligosaccharides. Cell membranes were fractionated by ultracentrifugation on linear sucrose density gradients, and the distribution of the fluorescence and proteins was measured. It is indicated that the oligosaccharides have bound to the plasma membrane. To examine the signal transduction in detail, several pathogenesis-related enzymes in cotton were measured. The results showed that the oligosaccharides enhanced enzyme activity and reduce the nocuity of cotton wile toxin.