INVESTIGADORES
FERNANDEZ ALVAREZ Ana Julia
artículos
Título:
Glutathione reductase activity and isoforms in leaves and roots of whet plants subjected to cadmium stress
Autor/es:
YANNARELLI, GUSTAVO G; FERNÁNDEZ ALVAREZ, ANA JULIA; SANTA-CRUZ, DIEGO M; TOMARO, MARÍA L
Revista:
PHYTOCHEMISTRY
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2007 vol. 68 p. 505 - 512
ISSN:
0031-9422
Resumen:
The behavior of glutathione reductase (GR, EC 1.6.4.2) activity and isoforms were analyzed in wheat (Triticum aestivum L.) leaves
and roots exposed to a chronic treatment with a toxic cadmium (Cd) concentration. A significant growth inhibition (up to 55%) was
found in leaves at 7, 14 and 21 days, whereas roots were affected (51%) only after three weeks. Wheat plants grown in the presence
of 100 lM Cd showed a time-dependent accumulation of this metal, with Cd concentration being 10-fold higher in roots than in leaves.
Nevertheless, lipid peroxidation was augmented in leaves in all experiments, but not in roots until 21 days. Cadmium treatment altered
neither the GR activity nor the isoform pattern in the leaves. However, GR activity increased 111% and 200% in roots at 7 and 14 days,
respectively, returning to control levels after 21 days. Three GR isoforms were found in roots of control and treated plants, two of which
were enhanced by Cd treatment at 7 and 14 days, as assessed by activity staining on native gels. The changes in the isoform pattern
modified the global kinetic properties of GR, thereby decreasing significantly (2.5-fold) the Michaelis constant (Km) value for oxidized
glutathione. Isozyme induction was not associated with an enhancement of GR mRNA and protein expression, indicating that posttranslational
modification could occur. Our data demonstrated that up-regulation of GR activity by the induction of distinctive isoforms
occurs as a defense mechanism against Cd-generated oxidative stress in roots.
Triticum aestivum L.) leaves
and roots exposed to a chronic treatment with a toxic cadmium (Cd) concentration. A significant growth inhibition (up to 55%) was
found in leaves at 7, 14 and 21 days, whereas roots were affected (51%) only after three weeks. Wheat plants grown in the presence
of 100 lM Cd showed a time-dependent accumulation of this metal, with Cd concentration being 10-fold higher in roots than in leaves.
Nevertheless, lipid peroxidation was augmented in leaves in all experiments, but not in roots until 21 days. Cadmium treatment altered
neither the GR activity nor the isoform pattern in the leaves. However, GR activity increased 111% and 200% in roots at 7 and 14 days,
respectively, returning to control levels after 21 days. Three GR isoforms were found in roots of control and treated plants, two of which
were enhanced by Cd treatment at 7 and 14 days, as assessed by activity staining on native gels. The changes in the isoform pattern
modified the global kinetic properties of GR, thereby decreasing significantly (2.5-fold) the Michaelis constant (Km) value for oxidized
glutathione. Isozyme induction was not associated with an enhancement of GR mRNA and protein expression, indicating that posttranslational
modification could occur. Our data demonstrated that up-regulation of GR activity by the induction of distinctive isoforms
occurs as a defense mechanism against Cd-generated oxidative stress in roots.
lM Cd showed a time-dependent accumulation of this metal, with Cd concentration being 10-fold higher in roots than in leaves.
Nevertheless, lipid peroxidation was augmented in leaves in all experiments, but not in roots until 21 days. Cadmium treatment altered
neither the GR activity nor the isoform pattern in the leaves. However, GR activity increased 111% and 200% in roots at 7 and 14 days,
respectively, returning to control levels after 21 days. Three GR isoforms were found in roots of control and treated plants, two of which
were enhanced by Cd treatment at 7 and 14 days, as assessed by activity staining on native gels. The changes in the isoform pattern
modified the global kinetic properties of GR, thereby decreasing significantly (2.5-fold) the Michaelis constant (Km) value for oxidized
glutathione. Isozyme induction was not associated with an enhancement of GR mRNA and protein expression, indicating that posttranslational
modification could occur. Our data demonstrated that up-regulation of GR activity by the induction of distinctive isoforms
occurs as a defense mechanism against Cd-generated oxidative stress in roots.
Km) value for oxidized
glutathione. Isozyme induction was not associated with an enhancement of GR mRNA and protein expression, indicating that posttranslational
modification could occur. Our data demonstrated that up-regulation of GR activity by the induction of distinctive isoforms
occurs as a defense mechanism against Cd-generated oxidative stress in roots.