149 P. Ahmad and M.N.V. Prasad (eds.), Abiotic Stress Responses in Plants: Metabolism, Productivity and Sustainability, DOI 10.1007/978-1-4614-0634-1_8, © Springer Science + Business Media, LLC 2012 8 Abstract Abiotic stresses severely affect the growth, development, and ultimately yield of the plant, which results in heavy economic losses and food crisis. Oxidative stress, which is associated with almost all the abiotic stresses, is due to over production of toxic reactive oxygen species (ROS) including superoxide ion, hydrogen peroxide, and hydroxyl radicals. Plants combat the oxidative stress via enzymatic and non-enzymatic machinery. Glutathione reductase (GR) is one of the potential enzymes of the enzy- matic antioxidant system, which sustains the reduced status of GSH via Ascorbate–Glutathione pathway and plays a vital role in maintenance of sulfhydryl (–SH) group and acts as a substrate for glutathione- S-trans- ferases. GR has been characterised and has been used in the transgenics to provide the plants with tolerance against the oxidative stress. Keywords Abiotic stress • GR location • GR structure • ROS scavenging • ROS signalling • Transgenic plants Role of Glutathione Reductase in Plant Abiotic Stress Peerzada Yasir Yousuf, Khalid Ul Rehman Hakeem, Ruby Chandna, and Parvaiz Ahmad 1 Introduction Environmental stresses, such as drought, salinity, cold, and heat cause adverse effects on the growth, productivity and trigger a series of morphological, physiological, biochemical, and molecular changes in plants. Abiotic stress is among the pri- mary cause of crop loss worldwide, reducing average yields for most major crop plants by more than 50%. Globally, approximately 25% of the agricultural land is saline (FAO 2009), and areas under drought are expected to increase further (Burke et al. 2006). Often crops are exposed to P.Y. Yousuf • K.U.R. Hakeem () Molecular Ecology Lab, Department of Botany, Jamia Hamdard, New Delhi 110062, India e-mail: Kur.hakeem@gmail.com R. Chandna Molecular Ecology Lab, Department of Botany, Jamia Hamdard, New Delhi 110062, India National Institute for Plant Genomics and Research, New Delhi, India P. Ahmad Department of Botany, A.S. College, University of Kashmir, Srinagar 190008, India e-mail: parvaizbot@yahoo.com