The Role of Glycogen Synthase Kinase-3 in Gibberellic Acid-Induced Chilling Tolerance and Defense Response in Postharvest Peach Fruit

Abstract

The induction of chilling tolerance and defense response by glycogen synthase kinase-3 (GSK-3) under gibberellic acid (GA3) treatment in peach fruit was explored at 4 °C up to 28 days. The fruits were treated with exogenous GA3 and bikinin (GSK-3 inhibitor). Results showed that exogenous GA3 alleviated chilling injury, and upregulated endogenous GA3 content in peach fruit. Furthermore, GSK-3 expression was activated by exogenous GA3 treatment. GA3 also upregulated gene expression of superoxide dismutase, peroxidase, catalase, glutathione reductase, glutathione S-transferase, and ascorbate peroxidase. Additionally, GA3 enhanced gene and protein expression of small ubiquitin-like modifier and gene expression of methionine sulfoxide reductase, and weakened gene expression of lipoxygenase and phospholipase D. These above impacts stimulated by exogenous GA3 were blocked by the addition of bikinin. Overall, GSK-3 was involved in stimulation of chilling tolerance and defense response under GA3 treatment in postharvest peach fruit.