Increase in galactolipid synthesis enhances stress tolerance

Abstract

The role of rice monogalactosyldiacylglycerol synthase gene (OsMGD) was examined under salinity stress by overexpressing it in tobacco (Nicotiana tabacum L. SR1). The transgenic tobacco showed better growth and maintained higher photosystem II photon yield under salinity stress than wild type. The transgenic tobacco showed 2.0 to 4.5 folds higher MGD activity than wild type and singnificantly higher contents of monogalactosyldiacylglycerol and digalactosyldiacylglycerol than wild type. Subcellular localization confirmed the presence of OsMGD protein in inner envelope of chloroplast. Ultrastructure observation of chloroplast showed slightly more dense grana structure in transgenic plant. Interestingly, the transgenic plant showed better growth in phosphorus deficient medium.