Impact of postharvest exogenous γ-aminobutyric acid treatment on cucumber fruit in response to chilling tolerance.

Low-temperature storage is generally used to extend postharvest lifetime and to inhibit decay of cucumber fruit, but it also enhances the intensity of chilling injury. The capability of γ-aminobutyric acid to enhance antioxidant enzyme activities and reduce chilling injury was studied in cucumber (Cucumis sativus L.) fruit stored at 1 °C for 5 weeks. The purpose of this study was to define if the GABA-induced modification in antioxidant system and phospholipase activity is linked to the reduced chilling injury in cold-stored cucumber fruit. Alleviation of chilling injury by GABA treatment was related to increased content of proline, endogenous GABA and enhanced activities of CAT and SOD, together with reduced activities of PLC, PLD and LOX. We suggest that PLC, LOX and PLD are associated with chilling injury initiation by involvement in a signaling pathway and membrane deterioration. Therefore the results obtained in this study suggest GABA's potential for postharvest applications for reducing chilling injury symptom in cucumber fruit.