Structural analysis of Pleurotus ferulae polysaccharide and its effects on plant fungal disease and plant growth.

A novel polysaccharide, named as PFP1-1 (23 kDa), was isolated from the fruiting body of Pleurotus ferulae. Structural analysis revealed that PFP1-1 is primarily composed of mannose, galactose, glucose and fucose, with a molar ratio of 41.50:41.92:4.65:1.93. Infrared spectroscopy analysis showed the presence of characteristic absorption peaks associated with polysaccharides. Further analysis using gas chromatography-mass spectrometry (GC-MS) and Nuclear Magnetic Resonance (NMR) indicated that the polysaccharide mainly composed of → 6) -α-D-Galp- (1 →, → 2,6) -α-D-Galp- (1 → and a small amount of → 4) -α-D-Glcp- (1 →. The branched chain is mainly composed of β-D-Manp- (1 → and α-D-Glcp- (1 → connected at the O-2 position of the sugar residue → 2,6) -α-D-Galp- (1 →. PFP1-1 exhibited significant antifungal activity against Rhizoctonia solani and promoted cucumber plant growth. The mycelial growth inhibition rate of PFP1-1 against R. solani reached 70 %. In pot experiments, cucumber seedlings treated with PFP1-1 demonstrated resistance to R. solani infection and the incidence rate was significantly reduced to 22.92 %. PFP1-1 increased the root length and fresh weight of cucumber seedlings and enhanced the stress and disease resistance of plants by increasing the activities of superoxide dismutase, peroxidase and polyphenol oxidase. In conclusion, the present study provides a theoretical and experimental basis for the application of P. ferulae polysaccharide in promoting plant growth and controlling plant diseases.