Effect of Metschnikowia pulcherrima and 24-epibrassinolide on grape quality preservation and Botrytis control during postharvest.

Postharvest deterioration in table grapes, driven by fungal pathogens and oxidative damage, remains a critical concern. This study evaluated the synergistic potential of 24-epibrassinolide (EBR) and Metschnikowia pulcherrima (Y) in preserving the quality of Red Globe grapes. The combined treatment of EBR and Y (YBR) significantly enhanced phenolic biosynthesis, elevating flavonoids and anthocyanin by 27.59 %, while suppressing Botrytis cinerea infection by 32.36 % through competitive microbial antagonism and induced systemic resistance. Notably, the EBR and YBR delayed fruit softening by mitigating peduncle and pedicel integrity, key determinants of cluster vitality and microbial ingress resistance. Antioxidant capacity remained elevated, countering reactive oxygen species accumulation. Structural preservation of pedicels and peduncles correlated with reduced water loss and delayed senescence, extending marketability. These outcomes highlight a dual mechanism YBR's biocontrol activity complemented EBR's phytohormonal regulation of stress-responsive pathways. The treatment offered a sustainable, non-chemical strategy to replace synthetic fungicides, addressing both biochemical quality and physical integrity. By integrating microbial and hormonal interventions, this approach advanced postharvest management, ensuring the prolonged shelf life and reduced spoilage in grapes, with broader implications for perishable fruit supply chains.