The effects of drought stress on morpho-physiological characters and expression of OsCat A in rice seedling

Drought stress is one of the most important limiting factors of crop plants in Iran and worldwide. To assess the response of mutant line MT149 to drought stress in comparison to parental cultivar Neda, a factorial experiment was conducted in a completely randomized design. Drought stress (-6 bar) was induced using poly ethylene glycol 6000 and leaf growth dynamics and chlorophyll a and b contents were evaluated in different time series (0, 12, 24 and 36 hours after stress treatment). Results showed that effects of genotype, time and stress were significant on all investigated characters. Also, mean`s comparisons showed that mutant line MT149 was superior over than itself parental counterpart. Furthermore, assessment of catalase gene isoform A (OsCat A) in different times after stress showed that parental cultivar Neda experienced a significant down-regulation of catalase A gene, while MT149 experienced a significant up-regulation of the gene in the same time. Based on the results of this research it can be concluded that one of evidences on a higher drought tolerance of MT149 is probably up-regulation of OsCat A to scavenge the ROS toxicities.