Glutathione-mediated biotic stress tolerance in plants

Abstract

Glutathione, along with ascorbate, is the main non-enzymatic antioxidant and redox buffers in plant cells. The reduced form of glutathione (GSH) is involved in the protection of cells from the oxidative damage induced by environmental challenges. GSH plays an important role in the recycling of reduced ascorbate in the reaction catalyzed by the enzyme dehydroascorbate reductase in the so-called ascorbate-glutathione cycle. Several studies reported that glutathione is involved in the induction of plant defense genes, and the increase in GSH and/or GSH-related enzymes is correlated with the resistance to different biotic challenges, including plant virus, bacteria, and fungi. Also, different works evidenced that decreases in GSH can be responsible for pathogen-elicited symptom development in susceptible plants. In that respect, it is important to mention that treatments leading to an increase in GSH and/or the redox state of glutathione can reduce the virus contents and/or the symptoms even during compatible plant-virus interactions. In addition, subcellular glutathione contents, reactive oxygen species production, and the antioxidative metabolism are considered valuable biotic stress indicators within plants during situations of pathogen attack.