Limited uptake, translocation and enhanced metabolic degradation contribute to glyphosate tolerance in Mucuna pruriens var. utilis plants

• Published in: Phytochemistry (Oxford) 2012, Vol.73 (1), p.34-41
• Main Authors: Rojano-Delgado, Antonia María, Cruz-Hipolito, Hugo, De Prado, Rafael, Luque de Castro, María Dolores, Franco, Antonio Rodríguez
• Format: Article
• Language: English
• Subjects: Amaranthus retroflexus; Capillary electrophoresis; Degradation; Dose-Response Relationship, Drug; Glycine - analogs & derivatives; Glycine - metabolism; Glycine - pharmacology; Glyphosate; Herbicides - metabolism; Herbicides - pharmacology; Metabolism; Molecular Structure; Mucuna - metabolism; Mucuna - ultrastructure; Mucuna pruriens; Resistance; Shikimic Acid - metabolism; Tolerance; Translocation
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2011.09.007

It is proposed that the innate tolerance of Mucuna pruriens to glyphosate is a result of the combined action of three traits, namely: limited uptake, impaired translocation and enhanced degradation. [Display omitted] ► Velvet bean, exhibited limited uptake and impaired translocation of glyphosate. ► Mucuna pruriens is capable degrading glyphosate to five metabolites as end products. ► It is the first report demonstrated the metabolism of glyphosate in a higher plant. ► The tolerance of velvet bean to glyphosate is possibly a result of the combined action of three traits. Velvet bean ( Mucuna pruriens, Fabaceae) plants exhibits an innate, very high resistance (i.e., tolerance) to glyphosate similar to that of plants which have acquired resistance to this herbicide as a trait. We analyzed the uptake of [ 14C]-glyphosate by leaves and its translocation to meristematic tissues, and used scanning electron micrographs to further analyze the cuticle and 3D capillary electrophoresis to investigate a putative metabolism capable of degrading the herbicide. Velvet bean exhibited limited uptake of glyphosate and impaired translocation of the compound to meristematic tissues. Also, for the first time in a higher plant, two concurrent pathways capable of degrading glyphosate to AMPA, Pi, glyoxylate, sarcosine and formaldehyde as end products were identified. Based on the results, the innate tolerance of velvet bean to glyphosate is possibly a result of the combined action of the previous three traits, namely: limited uptake, impaired translocation and enhanced degradation.