Exogenous glycine betaine treatment enhances chilling tolerance of peach fruit during cold storage

• Exogenous GB treatment reduced chilling injury in peaches during cold storage.
• The accumulation of endogenous GB was induced in GB-treated peaches.
• GABA and proline contents were enhanced by GB treatment in cold-stored peaches.
• GB treatment maintained high level of energy status in cold-stored peaches.

The effect of exogenous glycine betaine (GB) treatment on chilling injury (CI), energy status, endogenous GB, γ-aminobutyric acid (GABA) and proline content in cold-stored peach fruit was investigated. The results showed that GB treatment significantly prevented CI and maintained low flesh firmness and high extractable juice in peach fruit during cold storage. The accumulation of endogenous GB, GABA and proline contents in peaches was enhanced by GB treatment resulting from increasing activities of metabolism enzymes, including betaine aldehyde hydrogenase (BADH), glutamate decarboxylase (GAD), Δ1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine δ-aminotransferase (OAT). Moreover, high level of energy status in GB-treated peach fruit was found. These results indicated that GB treatment enhanced chilling tolerance in peaches due to induction of energy status, endogenous GB, GABA and proline contents, which prevented membrane damage. Thus, exogenous GB treatment could be a useful method to reduce CI in peach fruit during cold storage.