Antioxidant Defense, Chlorophyll Fluorescence and VvCBF4-VvNAC1 Genes Expression in Grapevine Cultivars (Vitis Vinifera L.) in Response to Cold Stress

Background: Cold stress is one of the limitative factors of different species of crops on the planet, causing significant damage to the Iranian agricultural industry every year. Grapes are the product of temperate warm zones and sensitive to early autumn cold and spring cold. The current study the effects of cold stress (+1 °C for 4, 8, and 16 hours) on three grapevine cultivars (Ghiziluzum, Khalili, and Perllete) were investigated. Results: The results showed that cold stress caused significant changes in the antioxidant and biochemicals content in the studied cultivars. Furthermore, examining the chlorophyll fluorescence indices, cold stress caused a significant increase in minimal fluorescence (F0), a decrease in maximal fluorescence (Fm), and the maximum photochemical quantum yield of photosystem II (Fv/Fm) in all cultivars. According to the obtained results, among the three studied cultivars, ‘Perllete’ with the highest increase in proline content and the activity of antioxidant enzymes and also, having the lowest accumulation of malondialdehyde, hydrogen peroxide, electrolyte leakage, and F0 as well as less decrease in Fm and Fv/Fm had the higher tolerance to the cold stress than ‘Ghiziluzum’ and ‘Khalili’ cultivars. VvCBF4 and VvNAC1 genes expression was increased in all three cultivars at +1 °C at 8 hours and then decreased. The increase in VvCBF4 and VvNAC1 genes expression in ‘Perllete’ cultivar was higher than the other two cultivars. Conclusion: ‘Perllete’ and ‘Ghiziluzum’ showed the highest tolerance to low temperature stress, respectively. ‘Khalili’ was sensitive to low temperature stress.