Spraying chitosan on cassava roots reduces postharvest deterioration by promoting wound healing and inducing disease resistance

Postharvest damage makes cassava roots vulnerable to pathogen infections and decay, which significantly hinders the development of the cassava industry. The objective of this study was to assess the antibacterial properties of chitosan in vitro, as well as its effect on wound healing and resistance in cassava roots. The findings demonstrated that the bacteriostatic effect of chitosan became increasingly prominent as the concentration of chitosan enhanced. Chitosan at a concentration of 0.5 mg/mL was revealed to significantly inhibit the germination of P. palmivora spores and damage to their structure. Moreover, chitosan activated the transcription of crucial genes and enzyme activities associated with the phenylpropane metabolism pathway in cassava roots, thus promoting rapid lignin accumulation and resulting in the early formation of a fracture layer. Chitosan was also found to enhance cassava root resistance by promoting the expression of pathogenesis-related proteins and the accumulation of flavonoids and total phenols. After 48 h of inoculation, cassava roots treated with chitosan exhibited a 51.4 % and 53.4 % decrease in lesion area for SC9 and SC6 varieties, respectively. The findings of this study offer a novel approach for managing postharvest deterioration of cassava roots.