MOLECULAR AND BIOCHEMICAL STUDY OF THE ANTIOXIDANT DEFENSE IN OXIDATIVE STRESS BY CADMIUM IN Glycine max LEAVES

FELICI CE; DEL OLMO J; PEREZ CHACA MV; MOLINA A; BIAGGIO VS; RANDAZZO G; MARSA S; ZIRULNIK F

Congreso; Sociedad de Biología de Cuyo; 2009

Antioxidant defense systems allow plants to develop a tolerance to contamination with cadmium (Cd). The objectives of this study were:-analyze the activity of glutathione reductase (GR), - the levels of GSH and -the gene expression of enzymes involved in the synthesis of GSH: γ-glutamilcysteine synthetase (γECS), glutathione synthetase (GSHS) and GR. Soybean seeds were germinated and developed under controlled conditions. On the tenth day of development were subjected to cadmium poisoning (40 μM) for 4, 6, 24 h. The expressions of γECS, GSHS, GR were determined by RTPCR. We observed that the expression of γECS, GSHS as well as the GR have the same behavior, i.e. the treated leaves increased at 4 h and decreased from 6 h (p < 0.001). GR activity increased after 24 h. GSH decreased at 4 h, and increased significantly after 6 h (p < 0..05) Cd treatment revealed in the leaf a significant decrease in GSH content, this could be interpreted as a possible use of GSH in the early hours as an antioxidant molecule, which correlates with an elevated content of the oxidized form (GSSG) (previous own data). This decrease is reversed from 6 h to increase significantly at 24 h of treatment. The activity of GR in leaves increased significantly from 72 h. This variation would justify that the contributions to the pool of GSH by GR would be subsequent to possible contributions from the synthesis of its precursors.