Effect of salinity stress and application of salisylic acid on expression of TaSC and TaNIP genes in two bread wheat (Triticum aestivum L.) cultivars

Salinity is one of the environmental stresses that affects bread wheat grain yield in most parts of the world. One of the basic strategies to mitgiate the effect of non-biological stresses such as salinity is genetic improvement of crop plants. Identification of stress-associated genes is a prerequisite for genetic improvement. In the present study, the role of a number of genes in the aquaporin family and genes associated with the CDPK pathway in response to environmental stresses was identified as their expression profile analysis in response to salinity stress would facilitate breeding for salinity tolerance. In 2014, the expression of two genes TaNIP and TaSC was studied in two bread wheat cultivars "Bam" tolerant to salinity and "Tajan" sensitive to salinity under salinity stress (170 mM NaCl) and Non-saline conditions. The results showed that TaNIP expression in salt-tolerant cultivar (Bam) significantly increaseed in both leaf and root tissues under salinity stress conditions, but in sensitive cultivar (Tajan) the level of TaNIP expression, especially in leaf tissues, was lower and showed a decreasing trend. In cv. Bam in both leaf and root tissues, after 24 hours, TaSC expression increased in comparion to control. In cv. Tajan, the expression in leaf tissue was generally lower and after 24 hours, the expression level significantly decreased in comparion to control (non-saline). Moreover, expression analysis under the simultaneousapplication of salicylic acid andsodium chloride showed that the expression of both genes in leaf tissues of both bread wheat cultivars significantly increased and the gene expression showed an increasing trend. In conclusion, the results of this experiment indicated that the TaNIP and TaSC genes had different expression trends in tolerant and sensitive bread wheat cultivars under salinity stress conditions. Using salicylic acid as an elicitor also activated the hormonal transduction pathway, which induced the expression of both genes. These findings highlights the role of these genes in salinity tolerance of tolerant bread wheat cv. “Bam”.