Cadmium toxicity in transgenic Arabidopsis deficient in putrescine biosynthesis

IANNONE M.F.; ROSALES E.P.; GROPPA M.D.; BENAVIDES M.P.

Rosario, Santa Fe, Argentina

Congreso; XLII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2006

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Polyamines (PAs) are aliphatic amines with proposed antioxidant properties. Cadmium (Cd) is a strongly phytotoxic pollutant. The aim of this work was to evaluate Cd toxicity in a mutant deficient in putrescine (Put) biosynthesis to look into the relationship between PAs levels and oxidative stress. Arabidopsis Noosen (wild type) and transgenic adc2-1 were germinated and then transferred to soil for 20 days. Plants were irrigated with Hoagland solution (Controls) or 0.5 mM CdCl2 for 3 or 6 days. Chlorophyll, TBARS, H2O2 and PAs contents and SOD and CAT activities were measured. Cadmium decreased chlorophyll in both FN and adc2-1-treated plants in a similar manner. A slight increase in TBARS was observed in adc2-1 Cd-treated plants whereas H2O2 increased significantly in adc2-1 exposed to Cd, accompanied by a large inhibition in SOD and CAT activities. However, the basal activities of these enzymes were significantly higher in adc2-1 than in FN control plants. PAs were slightly reduced in adc2-1 plants respect to FN, as expected considering the deficiency in Put biosynthesis of the mutant. However, the three PAs were moderately increased or without changes in FN Cd-treated plants. Constitutive increased SOD and CAT activities in the mutant could be a compensation for a reduced capacity to synthesized PAs in adc2-1 plants, considering that both lines presented similar toxicity symptoms.