Exogenous glutathione-mediated abiotic stress tolerance in plants

Abstract

Glutathione (GSH), a major non-protein low-molecular-weight thiol tripeptide in plant cells, is involved in a variety of life processes, including cell differentiation, removal of free radicals and hydroperoxides, thiol-disulfide exchange, and the synthesis of phytochelatin. Along with its oxidized form (GSSG), GSH plays key roles in maintaining cellular redox homeostasiss and signaling, as well as in defense reactions. As a component of ascorbate-glutathione (AsA-GSH) and glyoxalase pathways, GSH is involved in the regulation of hydrogen peroxide and methylglyoxal levels, ensuring their signaling functions, which are necessary for normal growth, development, and stress tolerance. In plants, GSH metabolism also plays important functions in determining the degree of expression of defense-related genes during abiotic and biotic stresses. Plants easily uptake exogenously applied GSH, which is transported into cellular compartments inducing a series of physiological and biochemical processes, including the modulation of abiotic stress tolerance. Recent studies have shown the multiple roles of exogenous GSH in improving abiotic stress tolerance through the regulation of multiple stress responsive pathways; however, the precise molecular mechanisms of exogenous GSH-induced abiotic stress tolerance are largely unknown. This chapter provides an overview to highlight the involvement of exogenous GSH in modulating abiotic stress tolerance. We also highlight the possible mechanisms of uptake and transport of the exogenously applied GSH under stressful conditions.