Evidence for a direct link between glutathione biosynthesis and stress defense gene expression in Arabidopsis.
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 gamma-GLUTAMYLCYSTEINE SYNTHETASE 1 (GSH1), which encodes chloroplastic gamma-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.
Department of Disease and Stress Biology, John Ines Centre, Colney, Norwich, NR4 7UH, United Kingdom.
Louise
L
Ball
Gian-Paolo
GP
Accotto
Ulrike
U
Bechtold
Gary
G
Creissen
Dietmar
D
Funck
Ana
A
Jimenez
Baldeep
B
Kular
Nicola
N
Leyland
Jaime
J
Mejia-Carranza
Helen
H
Reynolds
Stanislaw
S
Karpinski
Philip M
PM
Mullineaux
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000235:genetics; D001424:Bacterial Infections / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000528:radiation effects; D017343:Genes, Plant / Q000235:genetics; D005721:Glutamate-Cysteine Ligase / Q000235:genetics / Q000378:metabolism*; D005978:Glutathione / Q000096:biosynthesis*; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D008027:Light; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation / Q000235:genetics; D018384:Oxidative Stress / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D010775:Photic Stimulation; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000235:genetics
D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D006360:Heat-Shock Proteins; D010544:Peroxidases; D005721:Glutamate-Cysteine Ligase; C493655:Gsh1 protein, Arabidopsis; D005978:Glutathione