Evaluation of Relative Changes in the Expression Level of SOS2, MYB-related and HD-ZIP Genes in Oil Seed Sunflower Lines under Salinity Stress

Numerous environmental factors affect the growth and development of crop plants. Salinity affects crop production through mineral imbalance (toxicity or deficiency of elements), osmotic and oxidative stresses. In this study, using real-time PCR technology, changes expression levels of SOS2, MYB-related and HD-ZIP genes were evaluated under different salinity stress conditions (2, 5, 8, 11 and 14 dS/m) in two different oil seed sunflower lines (AS5305 and 9CSA3). Leaf sampling was performed at 8-leaf stage at four times; 6, 12, 24 and 48 hours after salinity stress application. SOS2 involve in signal transduction and MYB-related and HD-ZIP act as transcription factors under abiotic stresses. According to the results, the expression pattern of all three genes is different in the studied lines in response to salinity stress. Comparison of the two lines shows that the major increase in expression occurred in line AS5305, and where an increase in expression in line 9CSA3 is seen, in comparison, the rate of increase in corresponding times and salinity is higher in line AS5305 (tolerant line) than that in line 9CSA3 (sensitive line). The results indicate the positive role of these genes in the mechanism of sunflower resistance to salinity stress. On the other hand, in this study, by confirming the resistance of AS5305 line to salinity stress at the molecular level, it is possible to potentially use this line in the production of salinity-resistant hybrid cultivars in plant breeding programs.