Significance of Glutathione Metabolism in Plants Under Stress

In higher plants the tripeptide glutathione (GSH; γ-glu-cys-gly) and its homologs homoglutathione (hGSH; γ-glu-cys-β-ala) and hydroxymethylglutathione (γ-glu-cys-ser) are generally thought to be the most abundant low molecular weight thiols (Kasai and Larsen 1980; Bergmann and Rennenberg 1993). As products of the plant’s primary metabolism, these compounds have received considerable attention during recent years, because they are not only involved in storage and distribution of reduced sulfur within the plant, and hence in the regulation of sulfur nutrition, but are also essential components of the plant’s defence system for environmental stress (Fig. 1).