Kojic acid induces resistance against Colletotrichum brevisporum and enhances antioxidant properties of postharvest papaya

Once harvested, papaya fruit is prone to rapid deterioration and spoilage by microorganisms leading to food loss. The current study aimed to evaluate the effect of kojic acid (KA) treatments (2 mM and 5 mM) on the resistance of postharvest papaya against Colletotrichum brevisporum , a hazardous fungal pathogen. The results indicated that KA treatment decreased the lesion length in papayas by 30% after 7 days of storage. In addition, KA promoted the activity of both superoxide dismutase (SOD) and catalase (CAT) enzymes. Consequently, a decrease in malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ) and nitric oxide (NO) contents was also observed. Furthermore, the application of KA enhanced the antioxidant activity and expression levels of several genes related to antioxidant properties and defense response in papaya. In this regard, the effects of KA on C. brevisporum -infected postharvest papaya were studied for the first time, revealing the ability of KA to induce disease resistance and enhance the antioxidant properties in postharvest papaya.