Mechanism of Action of Potato Glycoalkaloids against Fusarium solani

Abstract

The antifungal mechanism of potato glycoalkaloids was studied using a sensitive species, Fusarium solani. The effects of potato glycoalkaloids extract on the ultrastructure, membrane permeability, contents of reducing sugar, soluble sugar, soluble protein and mycelial fat of Fusarium solani were determined. Potato glycoalkaloids significantly affected F. solani mycelial morphology, resulting in bubbly mycelial cell walls, incomplete outer layer, discontinuous cell membrane, disorganized structures of mitochondria and other organelles, and visible leakage of cell contents. Investigation of material metabolism indicated that potato glycoalkaloids disrupted selective permeability of mycelial cell membranes; In the treatment group, the soluble protein content increased from 66.50 g mL-1 to 169.51 g mL-1 for 0-6 h, the soluble sugar content in extracellular fluid increased from 117.4 g mL-1 to 132.5 g mL-1 for 0-24 h, which were much higher than that of the control group, hindered hydrolysis of reducing sugar, affected nutrient absorption and utilization and inhibited decomposition metabolism of mycelia. Thus, potato glycoalkaloids altered the morphology of fungal mycelia, destroyed cell membrane structure, increased mycelial cell membrane permeability, and caused cell contents leakage, resulting in effective inhibition of growth and metabolism of plant pathogenic fungus and so could decrease the occurrence of plant disease.