Limited uptake, translocation and enhanced metabolic degradation contribute to glyphosate tolerance in Mucuna pruriens var. utilis plants.
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 [(14)C]-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.
Departamento de Química Agrícola, Edificio Marie Curie, Campus de Rabanales, Universidad de Córdoba, E-14071 Córdoba, Spain.
Antonia María
AM
Rojano-Delgado
Hugo
H
Cruz-Hipolito
Rafael
R
De Prado
María Dolores
MD
Luque de Castro
Antonio Rodríguez
AR
Franco
D004305:Dose-Response Relationship, Drug; D005998:Glycine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D006540:Herbicides / Q000378:metabolism* / Q000494:pharmacology; D015394:Molecular Structure; D031299:Mucuna / Q000378:metabolism* / Q000648:ultrastructure; D012765:Shikimic Acid / Q000378:metabolism; D000097797:Glyphosate
D005998:Glycine; D006540:Herbicides; D012765:Shikimic Acid; D000097797:Glyphosate