采后桃果实容易受到机械伤及病原菌侵染，低温冷藏可有效抑制果实采后腐烂。但桃果实属于冷敏性果实，对低温环境较敏感，在低温下贮藏较长时间易引起冷害。因此，研究桃果实采后冷害调控技术及其作用机理，已成为解决桃果实贮运保鲜问题的关键。我们前期研究发现γ -氨基丁酸（GABA）代谢与桃果实采后抗冷性密切相关。低温可以促进桃果实中GABA的积累，外源GABA 处理能够显著提高果实的抗冷性。但GABA 对冷敏感果实采后抗冷性调节机制仍不清楚。本项目以不同成熟度桃果实为试材，通过生理生化及分子生物学手段，研究在低温胁迫下GABA 对乙烯合成与信号转导的调控及对三羧酸循环的回补作用，以此来解释GABA 在调控桃果实采后抗冷性中的机制。该项目的研究不仅丰富了果实采后冷害相关知识及理论，同时为桃果实采后抗冷性的调控及保鲜新技术的开发提供了理论基础，因此本项目的实施具有重要的理论和应用价值。

Peach fruit is very perishable due to microbial decay and mechanical damage after harvest. Low temperature storage is an effective method to control postharvest decay and maintain fruit quality. However, chilling injury (CI), the major physiological disorder, limits the storage period and shelf life when peaches are stored at low temperature. Thus, alternative postharvest handlings to alleviate chilling and extend shelf life of peach are needed. Recently, we found that there was a close relationship between γ-aminobutyric acid (GABA) metabolism and chilling tolerance in postharvest peach fruit. Low temperature induced GABA accumulation in peaches and exogenous GABA alleviated CI in cold-stored fruit. However, the mode of action of GABA in reducing CI has not been clearly elucidated. This project will investigate the effect of GABA on ethylene biosyntheses and signal transduction as well as its anaplerosis role in tricarboxylic acid cycle in cold-stressed peaches with two different ripening stages to reveal the mechanism by which GABA induces chilling tolerance in peach fruit. The results of this project will be helpful not only to enrich the knowledge and insight of CI in postharvest fruit but also to provide theoretical support for chilling tolerance regulation and development of new storage techniques in peach storage and transportation.