Expression of Genes Related to Na+ Exclusion and Proline Accumulation in Tolerant and Susceptible Wheat Genotypes under Salt Stress

In the present investigation, expression of genes related to Na+ exclusion such as salt overly sensitive (TaSOS1) and Na+/H+ antiporter (TaNHX1) and proline accumulation such as pyrroline-5-carboxylate reductase (P5CR) and glutamate synthase (GOGAT) was studied in seedlings of Kharchia 65 (Kh 65, salt tolerant) and HD 2009 (sensitive) under salt stress (ECe, 12 dSm(-1)) and controlled conditions. As compared to HD 2009, Kh 65 showed significantly lower accumulation of Na+ (p<0.01) and higher accumulation of proline (p<0.05) in leaf blade under salt stress. The relative expression of TaSOS1 increased significantly (p<0.001) in roots of Kh 65 (4.31-fold) while it decreased in HD 2009. There was significantly higher (p<0.01) relative expression of TaNHX1 (27.57-fold) in leaf and 3.07-fold in roots of Kh 65 as compared to 3.65- and 0.87-fold increase in leaf and roots of HD 2009, respectively, under salt stress. There was significantly (p<0.05) higher accumulation of proline as compared to HD 2009 in leaf tissues. There was significantly higher (p<0.01) expression of P5CR (5.23-fold in leaf and 8.77-fold in the root) and glutamate synthase (6.0-fold in roots) in Kh 65 as compared to HD 2009. The study demonstrated that upregulation of genes for Na+ exclusion in root and compartmentation in leaf and increased proline concentration are associated with tolerance to salinity stress in wheat. The information will be useful for improving wheat genotypes for salt tolerance.