Role of Melatonin in Cell-Wall Disassembly and Chilling Tolerance in Cold-Stored Peach Fruit

Abstract

Melatonin reportedly increases chilling tolerance in postharvest peach fruit during cold storage, but information on its effects on cell-wall disassembly in chilling-injured peaches is limited. In this study, we investigated the role of cell-wall depolymerization in chilling-tolerance induction in melatonin-treated peaches. Treatment with 100 μM melatonin alleviated chilling symptoms (mealiness) characterized by a decrease in fruit firmness and increase in juice extractability in treated peaches during storage. The loss of neutral sugars, such as arabinose and galactose, in both the 1,2-cyclohexylenedinitrilotetraacetic acid (CDTA)- and NaCO-soluble fractions was observed at 7 days in treated peaches, but the contents increased after 28 days of storage. Atomic-force-microscopy (AFM) analysis revealed that the polysaccharide widths in the CDTA- and NaCO-soluble fractions in the treated fruit were mainly distributed in a shorter range, as compared with those in the control fruit. In addition, the expression profiles of a series of cell-wall-related genes showed that melatonin treatment maintained the balance between transcripts of PpPME and PpPG, which accompany the up-regulation of several other genes involved in cell-wall disassembly. Taken together, our results suggested that the reduced mealiness by melatonin was probably associated with its positive regulation of numerous cell-wall-modifying enzymes and proteins; thus, the depolymerization of the cell-wall polysaccharides in the peaches treated with melatonin was maintained, and the treated fruit could soften gradually during cold storage.

Melatonin ameliorates aluminum toxicity through enhancing aluminum exclusion and reestablishing redox homeostasis in roots of wheat

“…During tomato postharvest ripening, for example, the expressions of proteins contributing to cell wall modifying, such as polygalacturonase and pectin esterase1, was up‐regulated after melatonin treatment . It has also showed that melatonin positively regulated some enzymes involved in cell wall modifying, maintaining cell wall polysaccharide depolymerization in peach . In the present study, Al exposure increased the levels of pectin, HC1, and HC2, which was more prominent in the sensitive genotype.…”

Melatonin delays leaf senescence of Chinese flowering cabbage by suppressing ABFs‐mediated abscisic acid biosynthesis and chlorophyll degradation

“…Melatonin retards leaf senescence in several plants including barley and detached apple leaves . In addition, melatonin is effective in maintaining the quality of postharvest fruits such as peach, banana, and litchi . For harvested green leafy vegetables such as Chinese flowering cabbage, leaf senescence is the most important factors affecting its shelf‐life and nutritional value during the postharvest storage and distribution.…”

“…15,16 In addition, melatonin is effective in maintaining the quality of postharvest fruits such as peach, banana, and litchi. [41][42][43] For harvested green leafy vegetables such as Chinese flowering cabbage, leaf senescence is the most important factors affecting its shelflife and nutritional value during the postharvest storage and distribution. In this work, we found that exogenous application of melatonin-alleviated senescence changes in Chinese flowering cabbage, with melatonin treatment maintaining a higher value of Fv/Fm and total chlorophyll content, while inhibiting the expression of chlorophyll catabolic and senescence marker genes.…”

Melatonin Enhances Cold Tolerance by Regulating Energy and Proline Metabolism in Litchi Fruit

“…In addition to having plant growth regulator-like functions, MLT has been identified as a powerful quencher of free radicals and as an activator of the antioxidant system, contributing to the avoidance of cumulative oxidative damage to the cell membrane and cytoplasm [14,15]. Due to its natural attributes, MLT has been developed as a nutritive supplement that exhibits multiple healthcare functions, especially in improving sleep quality, protecting against aging, and modulating biological rhythms [16][17][18].Recently, the application of MLT has displayed better performance in abating CI through the improvement in cold tolerance in several harvested fruits, including peaches [19,20], tomatoes [21,22], and pomegranates [23,24]. MLT-conferred protection against chilling stress in these crops involves the inhibition of membrane lipid peroxidation, the reinforcement of cell wall structure, activated phenol metabolism, and promotion of the biosynthesis of osmotic-adjusting compounds.…”

“…Recently, the application of MLT has displayed better performance in abating CI through the improvement in cold tolerance in several harvested fruits, including peaches [19,20], tomatoes [21,22], and pomegranates [23,24]. MLT-conferred protection against chilling stress in these crops involves the inhibition of membrane lipid peroxidation, the reinforcement of cell wall structure, activated phenol metabolism, and promotion of the biosynthesis of osmotic-adjusting compounds.…”