The effect of salicylic acid foliar application on the expression pattern of genes encoding antioxidant enzymes of spring bread wheat (Triticum aestivum L.) under water deficit conditions

To investigate the expression pattern of genes encoding antioxidant enzymes under water deficit stress in spring bread wheat, a factorial experiment was conducted in a randomized complete block design in 2020. In this study, agronomic traits, enzyme-related traits, antioxidant activity as well as the amount of gene expression affected by irrigation and salicylic acid were measured. In this study, there was a significant difference between irrigation levels and salicylic acid in terms of the effect on all traits. There was a significant difference between interaction treatments in terms of the effect on all traits except spike length and 1000-kernel weight. Mean comparison of interaction treatments showed that foliar spraying of 1 mM salicylic acid under 100% plant water requirement treatment had the highest plant height (64.76 cm), number of tillers per plant (3.71), number of seeds per spike (21.2) Dry matter yield (15.14 g / plant) grain yield (10.68 g / plant), chlorophyll an (8.66 mg / g fresh weight), chlorophyll b (2.66 mg / g fresh weight), Carotenoids (4.13 mg / g wet weight). While the highest content of leaf proline (0.53 mg / g fresh weight), leaf phenol (Galic acid / 82 DW9 / 82), catalase activity (97.09 mMolH2O2 / min mg protein), ascorbate peroxidase (mMolH2O2) / min mg protein 03/120), superoxide dismutase (mMolH2O2 / min mg protein 89/330) was allocated to foliar application of 1 mg salicylic acid under 50% plant water requirement. In this study, water deficit stress and salicylic acid foliar application had a synergistic effect on increasing the activity of antioxidant enzymes. The highest expression of superoxide dismutase, polyphenol oxidase, and catalase genes was observed by foliar application of 1 and 2 mM salicylic acid, and the highest expression of ascorbate peroxidase gene was observed by 1 mM foliar application of salicylic acid under 50% plant water requirement treatment. Application of salicylic acid under irrigation 50 and 75% of plant water requirement increased the expression of antioxidant genes in comparison with salicylic acid control treatment in each plant water require treatments and under 100% plant water requirement.