Antioxidant enzyme activities and protein profiling under salt stress in indica rice genotypes differing in salt tolerance

Abstract

The effect of NaCl stress (0–300 mM) was investigated in terms of antioxidant enzymes activity and their isozymatic pattern and SDS-PAGE proteins banding pattern in three rice cultivars (cvs), Panvel-3 (tolerant), Kalarata (moderately tolerant) and Karjat-3 (sensitive). Interestingly, superoxide dismutase activity in roots and glutathione reductase activity in both shoots and roots were decreased significantly under high salinity levels in Karjat-3 and Kalarata, while, a sharp increase was observed in Panvel-3. Catalase and peroxidase activities were increased with salt stress of all cvs, with highest magnitude in Panvel-3. There was an induction of two new POX isoforms in Panvel-3 and Kalarata in stressed plants. Four SOD isoforms were observed in all the genotypes, irrespective of non/saline conditions. Total 33 proteins bands ranging from 17–154.5 kDa were either expressed de novo or up/down-accumulated due to NaCl stress. In Panvel-3, three new bands, one of 32 kDa in shoots while two of 37 and 116.7 kDa appeared in roots under salt stress. A new band of 37 kDa was also observed in roots of Kalarata under salinity stress. Thus, salinity tolerance nature of Panvel-3 may be correlated with higher enzyme activities and expression of some new polypeptides under salt stress.