γ-Aminobutyric acid delays senescence of blueberry fruit by regulation of reactive oxygen species metabolism and phenylpropanoid pathway

The aim of this study is to investigate the effects of γ-aminobutyric acid (GABA) treatment after harvest on the reactive oxygen species metabolism and phenylpropanoid pathway of blue berry fruit. Blueberry fruit were dipped in 1 mmol/L GABA solution for 10 min and stored at 4 °C and the fruit treated with distilled water were used as the control. The results indicated that GABA increased the activities of phenylalanine ammonia lyase, cinnamate-4-hydroxylase, 4-coumarate/coenzyme A ligase and polyphenol oxidase. In addition, GABA treatment enhanced the activities of superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase, peroxidase and hydrogen peroxide content. Moreover, the accumulation of total phenolics and flavonoids in the fruit were enhanced by GABA treatment. These results suggest that GABA treatment could prolong the shelf life and delay the senescence of blueberry fruit by regulating phenylpropanoid pathway and reactive oxygen species metabolism.