The effect of GABA on biochemical properties and expression of CBF1-CBF4 genes in grapes under cold stress

Cold stress is one of the sudden stresses and causes a lot of damage to agricultural products. Plants, despite having open cold stress tolerance mechanisms, are not able to act at the rate of stress development in the region. . The use of hormonal and quasi-hormonal compounds can reduce the damage caused by cold to some extent. For this purpose, the function of gamma-aminobutyric acid (GABA) on biochemical properties and expression of cold-tolerant genes in grape seedlings was investigated. In this study, to reduce cold stress losses from GABA leaf spray in the form of a randomized complete block design in three replications and in 3 concentrations (zero (control), 20.10 mM) on annual grape cuttings, Rish Baba cultivar (tolerant) and Yaghooti cultivar (susceptible) were used zero (control), 4, 8 and 10 hours) sampling was performed and in the first experiment biochemical parameters such as antioxidant content (total DPPH), phenol alcohol, and superoxide dismutase activity were examined, in the second experiment the treatment samples GABA at a concentration of 20 mM at 8 and 10 hours after application of stress in comparison with other treatments in both cultivars showed the most positive effect to counteract the effects of cold, so entered the molecular study and thus gene expression of CBF1, CBF2, CBF3 and CBF4 genes involved in cold were examined by Real Time-PCR. The results showed that GABA increases plant signaling and production of antioxidant compounds and is able to inhibit free radicals produced during stress. It also strengthens the signaling inside the plant and raises the expression level of resistance in grapes 8 and 10 hours after the application of cold stress. The transcription factor CBF2 has the highest expression level among GABA treated cultivars at a concentration of 20 mM has increased the resistance level in grape seedlings to an acceptable level.