Cu,Zn-superoxide dismutase is differently regulated by cadmium and lead in roots of soybean seedlings

Abstract

The cadmium (Cd2+) and lead (Pb2+)-induced changes in Cu,Zn-SOD gene expression on the level of mRNA accumulation and enzyme activity were analyzed in roots of soybean (Glycine max) seedlings. The Cd2+ caused the induction of copper–zinc superoxide dismutase (Cu,Zn-SOD) mRNA accumulation, at each analyzed metal concentration (5–25 mg/l), whereas in Pb2+-treated roots this effect was observed only at the medium metal concentrations (50–100 mg/l of Pb2+). The analysis of Cu,Zn-SOD activity proved an increase in enzyme activity during Cd2+/Pb2+ stresses, however in Pb2+-treated plants the activity of enzyme was not correlated with respective mRNAs level. Presented data suggest that different metals may act on various level of Cu,Zn-SOD expression in plants exposed to heavy metals stress.