Expression of dehydrin and antioxidant genes and enzymatic antioxidant defense under drought stress in wild relatives of wheat

The aims of this study were to investigate different species of Triticum and Aegilops in terms of the expression pattern of ascorbate peroxidase, superoxide dismutase, and guaiacol peroxidase encoding genes along with the wheat dehydrin gene, wdhn13, which is involved in the induction of tolerance to drought stress. The study also explored the enzyme activity of these three antioxidant enzymes under drought stress. There was a significant difference in the expression level of the four studied genes, Wdhn13, APX, SOD and GPX, between the well-watered and drought stress (FC = 100% and FC = 25%) treatments and among the examined species. The relative expression of Wdhn13 under conditions of drought was higher in T. boeoticum and Ae. crassa compared to the tolerant reference cultivar (Sirvan) and the rest of the wild species. Ae. tauschii showed the highest expression of the APX gene, and the SOD and GPX genes were up-regulated in Ae. tauschii and T. boeoticum at the drought-stressed conditions. The highest APX, GPX and SOD enzyme activities under the drought-stressed conditions were observed in Ae. crassa, T. boeoticum and Ae. neglecta, respectively. The results indicated that there was relevant correspondence between the genetically determined tolerance of wheat species (i.e. the gene transcript levels) and their antioxidant enzyme activities. The species having A(b) (T. boeoticum), D (Ae. tauschii) and D (Ae. tauschii and Ae.crassa) genomes had a higher expression of GPX, SOD, and APX genes, respectively.