Figure 10.

Schematic representation on the role of GGTs in salt stress tolerance in mycorrhizal E. angustifolia seedlings. Arrows indicate intracellular metabolic fluxes and intercompartment transport. Metabolites are in black, and enzymes in white. For simplicity, not all possible reactions are shown in the figure. GSH is synthesized in the cytosol by the enzymes GSH from Glu, Cys and Gly. Degradation of GSSG occurs in the apoplast and vacuole by GGTs. This pathway recycles Glu, Cys and Gly, which can be taken up by the cell and serve in GSH re-synthesis. GGTs catalyzes the degradation of GS conjugates in the vacuole. GSH pools are present in mitochondrion, chloroplast, apoplast, cytosol and nucleus. Abbreviations: GGTs, gamma-glutamyl transpeptidases; GSSG, glutathione disulphide; GSH, glutathione; GS-conjugates, glutathione S-conjugates; Glu, glutamate; Gly, glycine; Cys, cysteine; ROS, reactive oxygen species.