Evaluation of Catalase and DREB-2 Gene Expression in Maize (Zea mays L.) Genotypes under Water Deficit Stress Condition

Abiotic stresses, especially water deficit stress in plants, cause oxidative stress and as a result, they produce reactive oxygen species (ROS) and cause serious damage to the DNA, protein and internal structure of plants. Plants have enzymatic and non-enzymatic defense mechanisms and systems to deal with these stresses. Currently due to climate changes, Water deficit stress is one of the problems of agricultural production. Given the importance of molecular studies and molecular and enzymatic responses of plants under abiotic stress conditions, therefore, relative expression of catalase and DREB-2 genes were studied by RT-PCR and catalase enzymatic activity were studied in SC706 and SC260 genotypes. The experiment was performed as a split plot based on a randomized complete block design with three replications and three irrigation conditions of (normal irrigation, intermediate stress and severe water deficit stress) under field condition. Results of relative expression analysis of genes showed a significant difference between the treatments so that by increasing the intensity of water stress compared to normal irrigation, the amount of enzyme activity and relative expression of the studied genes were increased. Under severe and intermediate water deficit stress, compared to normal irrigation, DREB-2 gene showed the highest increase with 690 and 211% respectively. In this study, based on the activity of catalase enzyme and the expression of CAT genes, DREB2 of SC706 genotype had higher performance than SC260, more appropriate physiological-molecular behavior and more expression of genes, which indicates more tolerance of SC706 genotype than SC260. The stress conditions applied in this study are the results that can be used in molecular breeding programs of maize.