Antioxidant Enzyme and Cytochrome P450 Activities Are Involved in Horseweed (Conyza Sumatrensis) Resistance to Glyphosate

The intensive global use of glyphosate has led to the evolution resistant (GR) weed species, including economically damaging horseweed (Conyza sumatrensis). We evaluated resistance mechanisms C. sumatrensis. While 5-enolpyruvylshikimate-3-phosphate synthase activity was similar between and nonresistant biotypes, plants from GR population accumulated lower shikimate levels than susceptible ones, suggesting absence target-site mechanisms. Decreases over time in concentrations leaves were not accompanied by increases their stem roots, indicating distribution rates plants. early appearance aminomethylphosphonic acid (the main metabolite) leaves, as well its presence only stems roots plants, suggests faster metabolism ones. treated with also showed greater antioxidant (ascorbate peroxidase [APX] catalase [CAT]) cytochrome P450-enzyme activities, great capacity avoid glyphosate-induced oxidative stress. Three non-target (reduced translocation, increased metabolism, activity) therefore confer sumatrensis This is first that APX, CAT activities are related