: Pitaya, a non-climacteric fruit commonly cultivated in tropical and subtropical regions, is valued for its nutritional benefits but is highly susceptible to chilling injury (CI) when stored below 6°C. This study investigates the role of γ-aminobutyric acid (GABA) in mitigating CI during six weeks of cold storage at 5 ± 1°C. Findings reveal that GABA treatment markedly suppressed CI severity up to 3 times in pitaya fruit compared with the control during cold storage. Decay incidence reached 62.3% in untreated fruit, whereas treated fruit exhibited 22.0% lower decay incidence. GABA also effectively preserved fruit quality by reducing weight loss from 10.9% in the control to 6.3% while maintaining higher total soluble solids (1.1-fold increase) and titratable acidity (0.9-fold higher than control). Moreover, GABA significantly alleviated oxidative stress, as evidenced by reduced malondialdehyde accumulation and H 2 O 2 levels (2.7-fold lower) together with decreased superoxide anion production. These effects were accompanied by enhanced antioxidant defense, with increased activities of superoxide dismutase, peroxidase, and ascorbate peroxidase. In addition, GABA treatment promoted proline accumulation, up to 1.4-fold higher than in control, and suppressed respiration rates during storage. Transcriptomic analysis further revealed that GABA modulated the phenylpropanoid biosynthesis pathway, including key genes PAL , C4H , and 4CL , and influenced auxin, ethylene, and abscisic acid signaling pathways associated with stress responses and fruit senescence. Collectively, these results indicate that GABA mitigates chilling injury in pitaya by enhancing antioxidant capacity and regulating phenylpropanoid metabolism and hormonal signaling, thereby maintaining postharvest fruit quality during cold storage.
Sabir et al. (Fri,) studied this question.