Conference Proceeding

Concurrent Overexpression of OsGS1;1 and OsGS2 Genes in Transgenic Rice (Oryza sativa L.): Impact on Tolerance to Abiotic Stresses and Phosphinothricin

Mr. Donald James

Glutamine synthetase (GS) is a key enzyme involved in the nitrogen metabolism of higher plants. Abiotic stresses severely limit crop productivity and are a constant threat to global food security. The activity and expression of GS is known to be significantly modulated by various abiotic stresses. However, very few transgenic over expression studies of GS have studied its impact on abiotic stress tolerance. GS is also the target enzyme of the broad spectrum herbicide Glufosinate (active ingredient: phosphinothricin). In this study, we investigated the effect of concurrent over expression of the rice cytosolic GS1 (OsGS1;1) and chloroplastic GS2 (OsGS2) genes in transgenic rice on its tolerance to abiotic stresses and the herbicide Glufosinate. Our results demonstrate that the OsGS1;1 and OsGS2 co-overexpressing transgenic rice plants had enhanced tolerance to osmotic and salinity stress at the seedling stage, as evidenced by higher fresh weight, chlorophyll content, relative water content, higher levels of proline and lower electrolyte leakage and malondialdehyde (MDA) content as compared to the respective wild type (wt) controls. The transgenic lines also showed considerably enhanced photosynthetic and agronomic performance under drought and salinity stress imposed during the reproductive stage. The grain filling rates of the transgenic rice plants under salinity stress (58.2 + 4.5%) and drought stress (64.6 + 4.7%) were significantly higher than control plants, thereby leading to higher yields Preliminary analysis also revealed that the transgenic lines had improved tolerance to methyl viologen induced photo-oxidative stress. Taken together, our results demonstrate that the concurrent over expression of OsGS1;1 and OsGS2 isoforms in rice enhanced physiological tolerance and agronomic performance under adverse abiotic stress conditions, apparently acting through multiple mechanistic routes. The transgenic rice plants also showed limited tolerance to the herbicide Glufosinate.

Published: 08 November 2017


Copyright: © 2017 Mr. Donald James. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.