Exogenously Applied Chitosan and Chitosan Nanoparticles Improved Apple Fruit Resistance to Blue Mold, Upregulated Defense-Related Genes Expression, and Maintained Fruit Quality

Blue rot disease caused by Penicillium expansum is one of the most widespread fungal diseases that affects apples worldwide. This work was to verify effect chitosan (2 and 4 g/L) its nano-form (0.2 0.4 against blue on their expression six defense-related genes as well fruit quality parameters. Regarding incidence, in cases, NPs performed better compared raw materials for both artificial natural infections. The highest efficacy obtained at g/L infection 2019 2020 seasons. All treatments kept parameters regarding firmness, total soluble solids, titratable acidity As expected, exogenous application bulk form triggered an increase levels including chitinase, peroxidase, ?-1,3-glucanase, Xyloglucan endotransglycosylase (XET), pathogenesis-related protein (PR8), phenylalanine ammonia lyase-1 (PAL1). Moreover, mRNA quantity all studied detected leaves treated with concentrations other treatments. Chitosan can be considered eco-friendly effective approach mold integrated into management programs maintain postharvest extend shelf life fruits.