Reduction of agri-food wastes, as well as extending the shelf-life and protection of perishable fruits by alter-native and eco-friendly solutions, in a circular economy context, are pivotal global challenges. In this study, the in vitro antifungal activity of two different chitosans (unbleached, called PEND, and bleached, named PEDEC) derived from an innovative and highly sustainable source, that is the exoskeletons of pupal exuviae of the bioconverter insect Hermetia illucens (L.) (Diptera: Stratiomyidae), against Botrytis cinerea and Fusarium spp. was investigated. Concentrations of 0, 0.06, 0.125, 0.25, 0.5, and 1 mg mL-1 of each chitosan were used in MIC (minimum inhibitory concentration) assays. PEND at 0.5 mg mL-1 (determined from MIC assay) significantly reduced mycelial growth and changed morphology (e.g. larger vesicles in the mycelium, cellular disorganization, hyphal coiling) and ultrastructural damages of fungi when observed by scanning elec-tron microscopy of B. cinerea, F. sporotrichioides and F. oxysporum f. sp. lycopersici, compared with negative control. Chitosans were then tested as protective treatments for postharvest storage of strawberry and grape, PEND resulting in a significant protection against artificially inoculated B. cinerea at doses of 0.5 and 1 mg mL-1. Commercial chitosan (K) was used as a control in all trials. The results open the door to the employment of H. illucens as an innovative, sustainable, natural source and potentially alternative to crustaceans to obtain chitosan to be used for plant protection.
Antifungal activity of an innovative chitosan derived from insects
A De Stradis;
2023
Abstract
Reduction of agri-food wastes, as well as extending the shelf-life and protection of perishable fruits by alter-native and eco-friendly solutions, in a circular economy context, are pivotal global challenges. In this study, the in vitro antifungal activity of two different chitosans (unbleached, called PEND, and bleached, named PEDEC) derived from an innovative and highly sustainable source, that is the exoskeletons of pupal exuviae of the bioconverter insect Hermetia illucens (L.) (Diptera: Stratiomyidae), against Botrytis cinerea and Fusarium spp. was investigated. Concentrations of 0, 0.06, 0.125, 0.25, 0.5, and 1 mg mL-1 of each chitosan were used in MIC (minimum inhibitory concentration) assays. PEND at 0.5 mg mL-1 (determined from MIC assay) significantly reduced mycelial growth and changed morphology (e.g. larger vesicles in the mycelium, cellular disorganization, hyphal coiling) and ultrastructural damages of fungi when observed by scanning elec-tron microscopy of B. cinerea, F. sporotrichioides and F. oxysporum f. sp. lycopersici, compared with negative control. Chitosans were then tested as protective treatments for postharvest storage of strawberry and grape, PEND resulting in a significant protection against artificially inoculated B. cinerea at doses of 0.5 and 1 mg mL-1. Commercial chitosan (K) was used as a control in all trials. The results open the door to the employment of H. illucens as an innovative, sustainable, natural source and potentially alternative to crustaceans to obtain chitosan to be used for plant protection.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
