Enzyme changes study and expression evaluation of some important genes in salinity tolerance in four varieties of rice under hydroponic conditions

Salinity is one of the most important growth limiting factors and rice production in arid and semi-arid regions of the world. In order to investigate the effect of salinity stress on biochemical characteristics and the expression of some inducible genes in the seedling stage of rice, an experiment in the form of chopped plots with a basic design of randomized complete blocks were performed with four replications. The main factor included five levels of zero (control), 50, 100, 150 and 200 mM sodium chloride to create salinity stress. Salinity levels were applied along with Yoshida's nutrient solution in a hydroponic system. The sub-factor included four varieties of rice (Kashuri, Shiroodi, Tarem and Kohsar). In this research, the cellular oxidation level index (TBARM), enzyme activities and expression of some important antioxidant genes, including catalase, superoxide dismutase, ascorbic peroxidase, and the TCTP transcription factor, were investigated. The results of the variance analysis of the data showed that the difference between cultivars and salinity levels for all studied traits was significant at the probability level of 1%. Also, by increasing the salinity level, the activity of the studied enzymes and the expression of catalase, superoxide dismutase, ascorbic peroxidase and TCTP genes increased. According to the obtained results, Shiroudi and Kohsar cultivars were identified as salinity tolerant cultivars.