Low molecular weight chitosan is an effective antifungal agent against Botryosphaeria sp. and preservative agent for pear (Pyrus) fruits

• Published in: International journal of biological macromolecules Vol. 95; pp. 1135 - 1143
• Main Authors: Wang, Yunguang, Li, Bin, Zhang, Xuedan, Peng, Nan, Mei, Yuxia, Liang, Yunxiang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2017
• Subjects: Antifungal activity; Antifungal Agents - chemistry; Antifungal Agents - pharmacology; antifungal properties; apoptosis; Apoptosis - drug effects; biomass; Botryosphaeria; Botryosphaeria sp; catechol oxidase; Catechol Oxidase - immunology; Catechol Oxidase - metabolism; chitinase; Chitinases - immunology; Chitinases - metabolism; chitosan; Chitosan - chemistry; Chitosan - pharmacology; enzymatic hydrolysis; Enzyme Activation - drug effects; ergosterol; Ergosterol - antagonists & inhibitors; Ergosterol - biosynthesis; Food Preservatives - chemistry; Food Preservatives - pharmacology; Fruit - drug effects; Fruit - enzymology; Fruit - microbiology; fruits; fungal growth; fungi; Hydrolysis; hyphae; Hyphae - classification; Hyphae - drug effects; Hyphae - growth & development; Hyphae - ultrastructure; Low molecular weight chitosan (LMWC); membrane potential; Membrane Potential, Mitochondrial - drug effects; Microbial Sensitivity Tests; minimum inhibitory concentration; mitochondrial membrane; Molecular Weight; mycelium; nutritive value; Pear fruit; pears; peroxidase; Peroxidase - immunology; Peroxidase - metabolism; Phylogeny; Plant Proteins - agonists; Plant Proteins - immunology; Plant Proteins - metabolism; postharvest diseases; Preservative agent; Pyrus; Pyrus bretschneideri; Saccharomycetales - classification; Saccharomycetales - drug effects; Saccharomycetales - growth & development; Saccharomycetales - ultrastructure; transmission electron microscopy; weight loss; Antifungal activity; Pear fruit; Low molecular weight chitosan (LMWC); Preservative agent; Botryosphaeria sp
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2016.10.105

•A pathogenic fungal strain, Botryosphaeria sp.W-01, was isolated from decayed pear.•LMWC was shown to strongly inhibit W-01 growth in vitro.•Alteration membrane permeability was determined as the antifungal mechanism.•LMWC coating had a significant preservative effect on pear fruits.•LMWC activated several defense-related enzymes, and maintained nutritional value. Antifungal activity and preservative effect of a low molecular weight chitosan (LMWC) sample, derived from chitosan by enzymatic hydrolysis, were investigated in vitro and in vivo. A pathogenic fungal strain was isolated from decayed pear (Pyrus bretschneideri cv. “Huangguan”) fruit and identified as Botryosphaeria sp. W-01. LMWC was shown to strongly inhibit W-01 growth based on studies of minimum inhibitory concentration (MIC) and effects on mycelial biomass and radial growth of the fungus. LMWC treatment of W-01 cells reduced ergosterol synthesis and mitochondrial membrane potential (ΔY), early events of apoptosis. Transmission electron microscopy and confocal laser scanning microscopy studies revealed that LMWC penetrated inside W-01 hyphae, thereby inducing ultrastructural damage. LMWC coating had a significant preservative effect on wounded and nonwounded pear fruits, by inhibiting postharvest decay and browning processes. LMWC activated several defense-related enzymes (polyphenol oxidase, peroxidase, chitinase), maintained nutritional value, and slowed down weight loss. Our findings indicate the strong potential of LMWC as a natural preservative agent for fruits and vegetables.