Application of Γ-Aminobutyric Acid Treatment Differently Affects Physicochemical Characteristics of Tomato Fruits during Postharvest Storage

Abstract

The quality of tomato fruit, from harvest to human consumption, requires a lengthy period for shipping, storing, and marketing. γ-aminobutyric acid (GABA) is a good candidate because it is a natural substance produced by plants to defend themselves against stress conditions. In this study, the effect of post-harvest GABA treatments at 0 (control), 5 mM and, 20 mM on the physical and biochemical properties and the polysaccharide content of tomatoes during 28 days of storage were investigated. Our results indicated that 5 mM of GABA treatment increased firmness and shelf-life by maintaining the integrity of fruits compared to control and 20 mM of GABA treated fruits. The fruits treated with 5 mM of GABA decreased the amount of WSP and the expression of cell wall related genes Pectate lyase (PL) and Polygalacturonase (PG). There was not a clear difference in colour index (CI) values among all treated groups at the end of post-harvest storage. Moreover, the tomato fruits treated with 5 mM GABA also showed somewhat less ethylene production, respiration rate and expression level of two ethylene synthesis genes ACS2 and ACS4 towards the end of storage. These results suggested that treatment with 5 mM GABA could be a beneficial strategy for maintaining the morphological and biochemical quality of tomato under postharvest storage conditions.