Effect of salinity stress on physiological characteristics and protein profile of tolerant and sensitive barley (Hordeum vulgare L.) cultivars at vegetative growth stage

To study the variation of plant traits related to stress tolerance in tolerant and sensitive barley cultivars under salt stress conditions, an experiment was carried out as factorial arrangements in completely randomized design in Payame Noor University of Mahabad, Iran in 2018. Application of salinity stress of 250 mM of sodium chloride started from tillering stage, and leaf samples were taken at 0, 3, 6 and 9 days following application of salinity treatment.The results showed that salinity stress had adverse effect on morphological and physiological traits such as those traits involved in cell-water relation and photosynthetic traits of the plant. Salinity stress increased sodium ion concentration, but decreased potassium ion concentration, imbalanceed ionic concentrations and decreased K+:Na+ ratio in the cell. In addition, under salinity stress, electrolyte leakage, proline and glycine betaine concentrations were higher than non-stressed conditions. The results also showed that the highest significant decrease in traits was observed in the 9 days samples after the beginning of salinity stress. Overall, Afzal cultivar had better response to salinity stress. Analysis of proteome showed that seven protein spots were in common between the two barley cultivars. Mass spectrometry showed that most of the identified proteins were involved in antioxidant defense, and therefore, the most important common proteins in the two cultivars were involved in cellular homeostasis. In general, the lower expression of these common proteins in cv. Makouei (sensitive) compared to cv. Afzal (tolerant) resulted its lower performance under salinity stress.