Melatonin ameliorates chilling injury in green bell peppers during storage by regulating membrane lipid metabolism and antioxidant capacity

• Published in: Postharvest biology and technology Vol. 170; p. 111315
• Main Authors: Kong, Xi-man, Ge, Wan-ying, Wei, Bao-dong, Zhou, Qian, Zhou, Xin, Zhao, Ying-bo, Ji, Shu-juan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2020; Elsevier BV
• Subjects: Antioxidants; Antioxidation; Chilling; Cold stress; Cooling; Cytology; Enzymatic activity; Fatty acids; Green bell pepper; Injury prevention; Lipid metabolism; Lipid peroxidation; Lipids; Lipoxygenase; Liquid oxygen; Malondialdehyde; Melatonin; Membrane lipid peroxidation; Membrane permeability; Membranes; Peppers; Peroxidation; Phospholipase; Phospholipase D; Proline; Structural damage; Transcription; Green bell pepper; Melatonin; Cold stress; Antioxidation; Membrane lipid peroxidation
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2020.111315

[Display omitted] •Melatonin may alleviate cold-induced membrane lipid peroxidation.•Melatonin treatment increased the ratio of unsaturated to saturated fatty acids.•Melatonin lightened phospholipids degradation and gene expression of CaPLD and CaLOX.•Melatonin treatment may activate an antioxidant defense system of bell peppers.•Melatonin treatment may be a reliable method to relieve chilling injury. Melatonin is a kind of indoleamine that plays an important role against abiotic stress. In the current study, we investigated the effect of exogenous melatonin (100 μM) on bell pepper during storage at 4 °C for 20 d and afterward shelf at 20 °C for 3 d. Melatonin treatment reduced cell structure damage and lightened the increase in chilling injury incidence, membrane permeability, and malonaldehyde (MDA) content under cold stress. The membrane lipid content and the ratio of unsaturated to saturated fatty acids increased by reducing the enzymatic activity and transcripts of phospholipase D (PLD) and lipoxygenase (LOX). Besides, melatonin application also inhibited the transcription of CaNAC1, which is the direct targeted regulator of the CaPLD gene. In addition, peppers treated with melatonin had a higher proline content than untreated peppers. Moreover, melatonin triggered the antioxidation protection system in peppers to resist oxidative damage by up-regulating the transcription level of the CaSOD, CaPOD, CaCAT, and CaAPX genes. Our results show that melatonin treatment may be a reliable method to relieve chilling injury in bell pepper fruit via the alleviation of cold-induced membrane lipid peroxidation and activating an antioxidant defense system.