Catalase response in roots of wheat plants subjected to abiotic stress factors

RA BARCIA; LB PENA; CE AZPILICUETA; MP BENAVIDES; SM GALLEGO

Puerto Madryn

Congreso; XLVI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

SAIB

Adverse environmental growth conditions are related to oxidative stress production in plant cells. Catalase, CAT, (H O : H O 2 2 2 2 oxidoreductase; EC 1.11.1.6) is one of the most relevant antioxidant enzymes. It is found in all aerobic organisms and catalyses the dismutation of H O to O and H O. In Triticum aestivum (wheat) 2 2 2 2 two genes codes for this enzyme: cat1 and cat2. In the present work, CAT activity, isoforms and gene expression were studied in wheat roots under diverse abiotic stressors. Treatments with 1 and 10 μM CdCl , 0,5 μM paraquat (PQ), 1 mM H O and water deprivation 2 2 2 (22% polyethylene glycol) were performed using a floating culture 2+ system. Cd , PQ and H O decreased specific CAT activity (15, 20, 2 2 2+ 26 and 10% for 1 and 10 μM Cd , 0,5 μM PQ, 1 mM H O 2 2 respectively, respect to control values). On the other hand, water deficit increased absolute CAT activity, but this rise was related to an increment in root protein content. Two bands of CAT activity, corresponding to different isoforms, were detected in native PAGE. The number of CAT isoforms did not change in treated roots respect to control. Nevertheless, cat1 and cat2 gene expression were modified by treatments. Taken together, all these results indicated not only that catalase is an enzyme sensitive to abiotic stress factors but also its has a complex regulation that depended on the type of stress.