Evidence for a direct link between glutathione biosynthesis and stress defense gene expression in Arabidopsis

• Published in: The Plant cell 2004-09, Vol.16 (9), p.2448-2462
• Main Authors: Ball, L, Accotto, G.P, Bechtold, U, Creissen, G, Funck, D, Jimenez, A, Kular, B, Leyland, N, Carranza, J.M, Reynolds, H
• Format: Article
• Language: English
• Subjects: alleles; Antioxidants; APX2 gene; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins - biosynthesis; Arabidopsis Proteins - genetics; Arabidopsis thaliana; ascorbate peroxidase; bacterial diseases of plants; Bacterial Infections - genetics; Bacterial Infections - metabolism; Biosynthesis; Cadmium; defense mechanisms; DNA, Complementary - analysis; DNA, Complementary - genetics; Down-Regulation - genetics; enzyme activity; Enzymes; Gene expression; gene expression regulation; Gene Expression Regulation, Plant - genetics; Gene Expression Regulation, Plant - radiation effects; Genes; Genes, Plant - genetics; glutamate-cysteine ligase; Glutamate-Cysteine Ligase - genetics; Glutamate-Cysteine Ligase - metabolism; glutathione; Glutathione - biosynthesis; GSH1 gene; Heat-Shock Proteins - biosynthesis; Heat-Shock Proteins - genetics; Leaves; ligases; Light; light intensity; messenger RNA; Molecular Sequence Data; Mutagenesis; mutants; Mutation - genetics; Oxidative stress; Oxidative Stress - genetics; Oxidative Stress - physiology; Oxidative Stress - radiation effects; Peroxidases - genetics; Peroxidases - metabolism; Photic Stimulation; Plant cells; plant stress; Plants; Pseudomonas syringae; rax1-1 allele; RNA; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; Signal Transduction - genetics
• ISSN: 1040-4651; 1532-298X; 1532-298X
• DOI: 10.1105/tpc.104.022608

The mutant regulator of APX2 1-1 (rax1-1) was identified in Arabidopsis thaliana that constitutively expressed normally photooxidative stress-inducible ASCORBATE PEROXIDASE2 (APX2) and had ≥50% lowered foliar glutathione levels. Mapping revealed that rax1-1 is an allele of γ-GLUTAMYLCYSTEINE SYNTHETASE 1 (GSH1), which encodes chloroplastic γ-glutamylcysteine synthetase, the controlling step of glutathione biosynthesis. By comparison of rax1-1 with the GSH1 mutant cadmium hypersensitive 2, the expression of 32 stress-responsive genes was shown to be responsive to changed glutathione metabolism. Under photo-oxidative stress conditions, the expression of a wider set of defense-related genes was altered in the mutants. In wild-type plants, glutathione metabolism may play a key role in determining the degree of expression of defense genes controlled by several signaling pathways both before and during stress. This control may reflect the physiological state of the plant at the time of the onset of an environmental challenge and suggests that changes in glutathione metabolism may be one means of integrating the function of several signaling pathways.