Novel insights into modified atmosphere mediated cold tolerance in peach fruit during postharvest storage

Abstract

Internal browning is a common symptom of chilling injury (CI) of peach fruit during postharvest cold storage, leading to a significant loss in the marketplace. In this study, modified atmosphere (MA) storage was applied to mitigate the occurrence of CI in both ‘Jinxiu’ and ‘Zhonghuashoutao’ peach and the overall transcriptomic changes were profiled. In two cultivars, MA treatment elicited multiple chilling responses affecting production of reactive oxygen species (ROS) and lipid metabolisms, as well as jasmonic acid (JA), γ-aminobutyric acid (GABA) and proline synthesis, accompanied by accumulation of JAs (JA and JA-Ile), GABA and proline. Correlation analysis demonstrated that JAs and GABA served as significant regulators involved in cold tolerance under MA treatment. Weighted correlation network analysis (WGCNA) suggested that ethylene responsive factors (ERFs), WRKYs and NACs might serve as central transcription factors in the chilling-response pathway. Notably, PpERF61 was confirmed to activate the expression of JA biosynthetic genes Pp13S-LOX, PpAOS and PpOPR3 as well as GABA synthesis gene PpGAD. Taken together, this study unveils novel insights into the underlying mechanism of enhanced cold resistance in MA-treated peach fruit.