Chitosan oligosaccharide-chestnut flower polysaccharide composite for enhanced antifungal performance and mechanisms against Fusarium graminearum.

Effective antimicrobial substances were extracted from natural polymers for phytopathogenic fungi, a type of microorganisms that can cause plant diseases. A chitosan oligosaccharide-chestnut flower polysaccharide composite was synthesized with chitosan and polysaccharides extracted from chestnut flowers. The samples were characterized with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), nuclear magnetic resonance spectrometer (1H NMR), and scanning electron microscopy (SEM), confirming the successful preparation of the chitosan oligosaccharide-chestnut flower polysaccharide composite. In vitro antifungal experiments demonstrated that composite material achieved a maximum inhibition rate of 77.46 % against Fusarium graminearum mycelium at a concentration of 1000 μg/mL. The composite material promoted the germination of wheat seeds and enhanced the activity of defense enzymes against plant pathogens. Therefore, the composite material shows potential as an anti-phytopathogenic agent.