Cadmium-induced changes in antioxidant enzymes in suspension culture of soybean cells.

Abstract

Cadmium (Cd), similarly to other heavy metals, inhibits plant growth. We have recently showed that Cd(2+) either stimulates (1-4 microM) or inhibits (>or= 6 microM) growth of soybean (Glycine max L.) cells in suspension culture (Sobkowiak & Deckert, 2003, Plant Physiol Biochem. 41: 767-72). Here, soybean cell suspension cultures were treated with various concentrations of Cd(2+) (1-10 microM) and the following enzymes were analyzed by native electrophoresis: superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and ascorbate peroxidase (APOX). We found a significant correlation between the cadmium-induced changes of soybean cell culture growth and the isoenzyme pattern of the antioxidant enzymes. The results suggest that inhibition of growth and modification of antioxidant defense reactions appear in soybean cells when Cd(2+) concentration in culture medium increases only slightly, from 4 to 6 microM.

Cadmium effect on oxidative metabolism of pea (Pisum sativum L.) roots. Imaging of reactive oxygen species and nitric oxide accumulation in vivo

“…GPX was also downregulated probably by enzyme inhibition by the metal, such as that described in wheat roots (Converso, Fernández & Tomaro 2000). Reduction of GPX activity was also observed in pea leaves under the same experimental conditions , although opposite results were obtained in P. vulgaris leaves (Smeets et al 2005) and soybean cell cultures (Sobkowiak et al 2004). GR, a key enzyme of the ASC-GSH cycle (Jiménez et al 1997;, was down-regulated probably by oxidative modifications of the protein (Romero-Puertas et al 2002).…”

“…Thus, CAT activity was slightly down-regulated at transcriptional level. The decrease of CAT activity by Cd ions was also described in pea (Dixit et al 2001) and pine (Schützendübel et al 2001) roots, as well as in sunflower leaves (Laspina et al 2005), rice (Kuo & Kao 2004) and Arabidopsis leaves (Cho & Seo 2004), while the opposite effect was observed in radish roots (Vitória, Lea & Azevedo 2001) and soybean cell cultures (Sobkowiak et al 2004). GPX was also downregulated probably by enzyme inhibition by the metal, such as that described in wheat roots (Converso, Fernández & Tomaro 2000).…”

“…The analysis of total SOD activity in root extracts showed a slight increase by cadmium; however, the assay of total SOD activity in crude extracts can be subjected to interferences by compounds with mimicked SOD activity . Reduction of SOD activity induced by Cd was reported in wheat (Milone et al 2003) and bean plants (Cardinaels et al 1984), although the opposite effect was observed in sunflower (Laspina et al 2005), rice (Kuo & Kao 2004) and soybean cell cultures (Sobkowiak et al 2004).…”

Characterization of Cu/Zn-SOD enzyme activities and gene expression in soybean under low nitrogen stress

“…The number of soybean SOD enzyme bands was similar to that previously described in suspension culture of soybean cells. 22 According to the band shifts on PAGE, soybean SOD isoenzymes were classified into , and families, with different isoenzyme activities identified in different tissues. In leaf, almost no activity of .1 isoenzyme Table 3.…”

“…Sobkowiak et al found both of the Cd 2+ and Pb 2+ affected the activities of Cu/Zn-SOD isoenzymes (identified as isoenzyme in this study). 22 Pawlak et al confirmed that activities of Cu/Zn-SOD were also not affected by Cd 2+ and Pb 2+ , but the activities of Mn-SOD were not affected by Cd 2+ or Pb 2+ . 8 In this study, the intensity of one Cu/Zn-SOD isoenzyme .2 was increased under low nitrogen treatment rather than other SOD isoenzymes in the root of WS01-15, a soybean cultivar with high yield and high seed protein content mainly planted in the Huanghuai eco-region in China.…”