INVESTIGADORES
BALESTRASSE Karina Beatriz
artículos
Título:
Cadmium induced oxidative stress in soybean plants also by the accumulation of d-aminolevulinic acid
Autor/es:
NORIEGA, G; BALESTRASSE, K; BATLLE, A; TOMARO, M
Revista:
BIOMETALS
Editorial:
Springer
Referencias:
Año: 2007 vol. 20 p. 841 - 851
ISSN:
0966-0844
Resumen:
Cadmium toxicity has been extensively studied in
plants, however its biochemical mechanism of action has not yet been well
established. To fulfil this objective, four-weeks-old soybean nodulated plants
were treated with 200 lM Cd2+ for 48 h. d-aminolevulinic acid
dehydratase (ALA-D, E.C. 4.2.1.24) activity and protein expression, as well as
d-aminolevulinic acid (ALA)
and porphobilinogen (PBG) concentrations were determined in nodules, roots and leaves.
In vitro experiments carried out in leaves were performed using leaf discs to
evaluate the oxidant and antioxidant properties of ALA
and S-adenosyl-L-methinone (SAM), respectively. Oxidative stress parameters
such as thiobarbituric acid reactive substances (TBARS) and GSH levels as well
as superoxide dismutase (SOD, E.C. 1.15.1.1), and guaiacol peroxidase (GPOX, E.C.
1.11.1.7) were also determined. Cadmium treatment caused 100% inhibition of
ALA-D activity in roots and leaves, and 72% inhibition in nodules whereas
protein expression remained unaltered in the three studied tissues. Plants
accumulated ALA in nodules
(46%), roots (2.5-fold) and leaves (104%), respect to controls. From in vitro
experiments using leaf discs, exposed to ALA
or Cd2+ , it was found that TBARS levels were enhanced, while GSH
content and SOD and GPOX activities and expressions were diminished. The
protective role of SAM against oxidative stress generated by Cd2+ and
ALA was also demonstrated. Data
presented in this paper let us to suggest that accumulation of ALA
in nodules, roots and leaves of soybean plants due to treatment with Cd2+
is highly responsible for oxidative stress generation in these tissues.