Metalaxyl-induced changes in the antioxidant metabolism of Solanum nigrum L. suspension cells

• A reduction in cell growth was observed in a concentration-dependent manner with metalaxyl treatments.
• Solanum nigrumL. cell suspensions accumulated and/or degradated metalaxyl.
• Exposure of cell suspensions to metalaxyl resulted in the establishment of oxidative stress.
• Quantification of free proline showed the activation of the non-enzymatic antioxidant system.
• Metalaxyl induced an increase in the activity of enzymes belonging to the enzymatic antioxidant system (SOD, CAT and APX).

The antioxidant responses of Solanum nigrum L. cell suspension cultures to metalaxyl exposure were investigated. An increase in lipid peroxidation and hydrogen peroxide content, for both concentrations tested (20 mg L−1; 40 mg L−1) revealed the response of oxidative metabolism of cell suspensions to metalaxyl. Superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and ascorbate peroxidase (APX; EC 1.11.1.11) activities increased, particularly in the highest concentration of metalaxyl used. An analysis by non-denaturing polyacrylamide gel (PAGE) followed by staining for enzyme activity, revealed seven SOD isoenzymes, two CAT isoenzymes, and nine APX isoenzymes. Metalaxyl levels were quantified in the culture medium and results suggest that suspension cells were able to accumulate and/or degrade the fungicide five hours after exposure. SOD, CAT and APX isoenzymes were differently affected by the metalaxyl treatment. Results suggest that the higher concentration of metalaxyl induced oxidative stress to cell suspension cultures of S. nigrum.

A antioxidant response comprising SOD, CAT and APX enhanced activities reduced the oxidative damage due to the exposure of Solanum nigrum L. cell suspensions to metalaxyl.Figure optionsDownload as PowerPoint slide