Methyl Jasmonate Application Downregulates Drupelet Reversion and Enhances Phenolic Biosynthesis and Antioxidant Potential of Blackberries

Abstract Blackberry plants were sprayed with methyl jasmonate (MJ 0, 1, 2 or 3 mmol L −1 ), 2 weeks before tentative harvest maturity, to evaluate its influence on red drupelet reversion (RDR), antioxidant capacity and postharvest quality during cold storage up to 12 days. MJ significantly reduced RDR and weight loss while maintaining higher anthocyanins and flavonoids during cold storage for 12 days. MJ application upregulated phenolic metabolism by maintaining higher phenylalanine ammonia lyase activity, and showed higher total antioxidants, ascorbic acid, and glutathione content. MJ-treated blackberries displayed higher activities of superoxide dismutase, catalase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase enzymes, than control for 12 days of cold storage. Moreover, MJ-treated fruit suppressed the production of hydrogen peroxide radicals and malondialdehyde with lower activities of polyphenol oxidase and lipoxygenase enzymes. In conclusion, preharvest application of MJ has the potential to reduce RDR, improve antioxidant capacity and maintain fruit quality of cold stored blackberries.