Oligomycin and ATP treatment regulate the storability of fresh longan via modulating energy metabolism

Longan is an economically important fruit with a unique flavor and rich nutrition, but its storability is poor, manifested by a rapid senescence, disease development, and spoilage of fruit after harvesting. Increasing evidences have confirmed that energy status is closely related to the quality decline of fresh produces. However, the relationship between the energy status and the storability of fresh longan, as well as its regulatory mechanism remain unclear. Accordingly, this research investigated how oligomycin and ATP influenced the energy status for regulating the storability of postharvest longans and its acting mechanism. Compared with the control sample, the oligomycin-treated longan presented inferior visual appearance and lower nutrient contents, accompanied by the raised pulp breakdown index and fruit disease index, but the reduced level of commercially acceptable fruit. Moreover, lower expression levels of DlAACs , DlADNT1 , DlVMHAs and DlPMCAs , lower activities of H + -ATPase, Ca 2+ -ATPase and Mg 2+ -ATPase, and lower values of ATP, ADP and energy charge, but higher AMP level were shown in the oligomycin-treated sample. These findings indicated that the oligomycin treatment downregulated the expressions of DlAACs , DlADNT1 , DlVMHAs and DlPMCAs , and inhibited ATPases activities, which further impaired the conversion of ADP or AMP into ATP and accelerated ionic disequilibrium, thereby leading to energy insufficiency, and consequently exacerbating the quality decline and limiting the storability of fresh longan. Conversely, the opposite effects were shown in the ATP-treated longan, indicating ATP treatment improved the storability and quality maintenance via sustaining higher levels of energy status (ATP, ADP, and energy charge) and ATPase activities.