Functions of melatonin during postharvest of horticultural crops

Melatonin, a tryptophan-derived molecule, is endogenously generated in animal, plant, fungal and prokaryotic cells. Given its antioxidant properties, it is involved in a myriad of signaling functions associated with various aspects of plant growth and development. In higher plants, melatonin (Mel) interacts with plant regulators such as phytohormones, as well as reactive oxygen and nitrogen species including hydrogen peroxide (H2O2), nitric oxide (NO) and hydrogen sulfide (H2S). It shows great potential as a biotechnological tool to alleviate biotic and abiotic stress, to delay senescence and to conserve the sensory and nutritional quality of postharvest horticultural products which are of considerable economic importance worldwide. This review provides a comprehensive overview of the biochemistry of Mel, whose endogenous induction and exogenous application can play an important biotechnological role in enhancing the marketability and hence earnings from postharvest horticultural crops.Imam Khomeini International University, Iran, (to M.S.A.) Spanish Ministry of Science and Innovation, Science and Food Technology Area (PID2020-113029RB-I00 to M.B.A.); European Regional Development Fund co-financed grant from the Spanish Ministry of Economy and Competitiveness (PID2019-103924GB-I00 to F.J.C.); the Plan Andaluz de Investigación, Desarrollo e Innovación (P18-FR-1359 to F.J.C.); Junta de Andalucía (group BIO192 to F.J.C.), Spain.Peer reviewe