An Exogenous Pre-Storage Melatonin Alleviates Chilling Injury in Some Mango Fruit Cultivars, by Acting on the Enzymatic and Non-Enzymatic Antioxidant System

Renu Bhardwaj; Sunil Pareek; J. Abraham Domínguez-Avila; Gustavo A. Gonzalez-Aguilar; Daniel Valero; Maria Serrano

An Exogenous Pre-Storage Melatonin Alleviates Chilling Injury in Some Mango Fruit Cultivars, by Acting on the Enzymatic and Non-Enzymatic Antioxidant System

2022

Melatonin (MT) treatment (100 &micro:M, 2 h) was applied to four mango fruit cultivars (&lsquo:Langra&rsquo:, &lsquo:Chaunsa&rsquo:, &lsquo:Dashehari&rsquo:, and &lsquo:Gulab Jamun&rsquo:), before being stored at 5 &plusmn: 1 &deg:C for 28 d, in order to alleviate chilling injury (CI). Maximum CI reduction was observed in &lsquo:Langra&rsquo: mangoes, and minimum in &lsquo:Gulab Jamun&rsquo: mangoes. This positive effect on quality preservation was associated with an increased concentration of endogenous MT, which prevented the accumulation of reactive oxygen species (H2O2 and O2&middot:&minus:) and stimulated non-enzymatic antioxidants (total phenolic compounds and total flavonoids), possibly due to higher activity of phenylalanine ammonia lyase and tyrosine ammonia lyase. Increased antioxidant activity was also documented in MT-treated &lsquo:Langra&rsquo: mangoes, according to four different assays (DPPH, TEAC, FRAP, and CUPRAC) and higher activity of six antioxidant enzymes (superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase). In contrast, &lsquo:Gulab Jamun&rsquo: mangoes showed minimal or no positive effects on the aforementioned variables in response to the exogenous MT application. &lsquo:Chaunsa&rsquo: and &lsquo:Dashehari&rsquo: mangoes had some intermediate effects on their antioxidant system (enzymatic and non-enzymatic) and alleviation of CI, when treated with exogenous MT. We conclude that exogenous MT exerts a cultivar-dependent stimulating effect on the antioxidant system of mangoes, which results in an increase in the fruits&rsquo: resistance to low temperature.

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