Ascorbic acid as a master redox regulator of fruit ripening

Ascorbic acid plays an essential role in human health and its deficiency severely impacts physical well-being. Fruits are a good dietary source of ascorbic acid and thereby, its composition and strategies to increase total vitamin C contents in fruits have been reviewed previously. Nevertheless, ascorbic acid is also a fundamental antioxidant that regulates fruit ripening by its efficiency to eliminate reactive oxygen species and modulate the cellular redox state. The present review summarizes current knowledge on ascorbic acid from a plant physiological perspective both during preharvest and postharvest to dissect key regulatory points and offers an updated discussion on its capacity to regulate fruit ripening. At the same time, ascorbic acid capacity to modulate ethylene and abscisic acid signaling is discussed, together with its relevance to control the cellular redox state thereby fine-tuning fruit ripening onset and postharvest shelf-life. Finally, we emphasize the relevance of ascorbic acid to regulate fruit physiological disorders during postharvest and its relationship with current technologies of postharvest management.