Untitled

Abstract

Mitigating effect of exogenous spermidine (Spd) treatment on the reactive oxygen species (ROS) scavenging system in response to salinity has been investigated in root and shoot tissues of two Indica rice varieties, namely IR 36 (salt sensitive) and Nonabokra (salt-tolerant). Rice seedlings (5-Day old) were grown in 150mM sodium chloride (NaCl) in presence or absence of 1 mM Spd for 16 h and stress-evoked change in physiological parameters, accumulation of H2O2 content, gene expression and biochemical activities of three antioxidative enzymes, such as, catalase, ascorbate peroxidase and superoxide dismutase were determined. Plant growth retardation in terms of chlorophyll degradation, reduction in carotenoid content and enhanced anthocyanin content during salinity exposure were rescued due to external Spd supplementation.Moreover, exogenous application of Spd differentially influenced the antioxidative enzymes systems in root and shoot tissues of two rice cultivars of different sensitivity towards salt stress. The gene expression analyses of different antioxidative isoenzymes revealed that different isoforms of a particular antioxidative enzyme contributed unequally to make a direct correlation with their cumulative enzymes activities. In addition to that some in silico structural attributes including 3D protein structure, active site and ligand site prediction have added additional information on our existing knowledge that will be beneficial for the future investigation on the specific potential roles of different isoforms of those anti-oxygenic enzymes in stress management.