Catalase activity and expression in developing sunflower seeds as related to cadmium stress

CE AZPILICUETA,; ML TOMARO; SM GALLEGO

Rosario, Pcia Santa Fe, Argentina

Congreso; XLII Reunión anual de la Sociedad Artentina de Investigación en Bioquímica y Biología Molecular; 2006

SAIB

Sunflower seed development is associated with marked changes in catalase (CAT) activity. In mature seeds, CAT is located mainly in glyoxysomes. Although at least eight isoforms of CAT isoenzymes have been described, results from the association of 55 and 59 kDa subunits, four different genes, CATA1 to CATA4, have been identified in sunflower cotyledons. The objective of the present work was to evaluated CAT activity and expression in developing sunflower seeds as related to oxidative stress induced by cadmium. Sunflower seeds were imbibed in water (control) or concentrations up to 100 Cl2Cd µM and stored in dark at 24oC for 24 h. Seeds germinability was unaltered by cadmium under the assayed conditions. H2O2 production, measured as precipitation of 3,3 diamine bencidine, was observed in root apix with up to 10 µM cadmium concentration. In the seedlings, all CATAs transcripts were detected. Although CATA1 and CATA3 transcripts level increased with cadmium treatment, CATA2 and CATA4 decreased its expression. CAT activity in Cd-treated seedlings remained similar to control. Modification in the expression pattern of catalase subunits in seeds under cadmium treatment and no variation in the activity are indicating that new CAT isoforms synthesis are responsible of a major resistant to the stress condition.