Evaluation of low concentration glyphosate effect on horseradish peroxidase enzyme activity

Resumo

Among several pesticides used in agriculture, glyphosate herbicide is one of the most employed in crop fields in spite of its recognized toxic effects on human health and on the environment. Consecutive use of glyphosate in crops can cause significantly increase the severity of various diseases, reduced growth, impaired defenses and alter the physiology of plants affecting the susceptibility or tolerance to diseases. Peroxidase enzymes play an important role in some physiological and pathological processes, involving active oxygen species occurring at the level of plasma membrane and cell wall. The aim of this work was to evaluate the effect of glyphosate on the enzymatic activity of horseradish peroxidase. For this purpose, tests were conducted to determine the optimal pH range and then reaction kinetic where was added, the substrate (catechol), mediator (H₂O₂), glyphosate and enzyme (horseradish peroxidase), varying the substrate concentration glyphosate to assess the activity of this reaction and the influence of herbicide on the enzyme activity. Results demonstrate that glyphosate increases the activity of horseradish peroxidase in low concentration and can decrease the resistance of the plant to the entry of pathogens.