OsBAT1 Augments Salinity Stress Tolerance by Enhancing Detoxification of ROS and Expression of Stress-Responsive Genes in Transgenic Rice

Abstract

Coping with salinity-induced reduction in crop yield is essential for food security. Human leukocyte antigen-B associated transcript 1 (BAT1) also called as UAP56 is a DExD/H-box protein involved in messenger RNA (mRNA) splicing. Function of plant homologue of BAT1, especially its involvement in stress tolerance, has not been reported so far. Here, we demonstrate the localization of rice BAT1 (OsBAT1) in the nucleus and in the plasma membrane and its novel function in salinity stress tolerance in rice (Oryza sativa L. cv. IR64). Rice overexpressing OsBAT1 (T1 and T2 generations) show tolerance to high salinity (200 mM NaCl) stress. The T1 transgenics exhibited higher levels of biochemical parameters such as water and chlorophyll contents, net photosynthetic rate, stomatal conductance and intercellular CO2 content as compared to null-segregant (control) plants. The activities of ascorbate peroxidase, guaiacol peroxidase, malondialdehyde and glutathione reductase were significantly higher in transgenics indicating the presence of an efficient antioxidant defence system which helps to cope with salinity-induced oxidative damages. Agronomic parameters were also higher in transgenics as compared to control. Microarray analysis of OsBAT1 overexpressing transgenic lines revealed up-regulation of stress-responsive genes of different pathways including the spliceosome. Our results provide the first direct evidence for a promising function of OsBAT1 in mediating salinity stress response/tolerance in rice.