title: Liquid chromatography-diode array detection to study the metabolism of glufosinate in Triticum aestivum T-590 and influence of the genetic modification on its resistance.
abstract: The resistance to glufosinate of two lines-genetically modified (GM) and unmodified (T-590 and T-549, respectively)-of Triticum aestivum has been studied. In the GM line, the bar gene was introduced to increase the resistance to glufosinate. Experiments in a controlled growth chamber showed that line T-590 presented a high resistance to glufosinate with an ED50 value of 478.59 g active ingredient per hectare (g ai ha(-1)) versus 32.65 g ai ha(-1) for line T-549. The activity of glutamine synthetase (GS) in leaf extracts from both lines was investigated. The I50 for line T-590 was 694.10 μM glufosinate versus 55.46 μM for line T-549, with a resistance factor of 12.51. Metabolism studies showed a higher and faster penetration of glufosinate in line T-549 than in line T-590. LC-TOF/MS analysis of glufosinate metabolism at 48 h after herbicide treatment (300 g ai ha(-1)) revealed an 83.4% conversion of the herbicide (66.5% in N-acetyl-glufosinate metabolite), while in line T-549 conversion of the herbicide was about 40% (0% to N-acetyl-glufosinate). These results suggest that metabolism of glufosinate by the bar gene is a key mechanism of resistance in line T-590 that explains such high levels of herbicide tolerated by the plant, together with other mechanisms due to unmodified pathway, absorption and loss of glufosinate affinity for its target site.
authors.affiliation: Department of Agricultural Chemistry, C-3 Building, Campus of Rabanales, and Agroalimentary Excellence Campus, ceiA3, University of Córdoba, E-14071 Córdoba, Spain. Electronic address: q92rodea@uco.es.
authors.forename: Antonia María
authors.initials: AM
authors.lastname: Rojano-Delgado
authors.forename: Feliciano
authors.initials: F
authors.lastname: Priego-Capote
authors.forename: Francisco
authors.initials: F
authors.lastname: Barro
authors.forename: María Dolores Luque
authors.initials: MD
authors.lastname: de Castro
authors.forename: Rafael
authors.initials: R
authors.lastname: De Prado
mesh_terms: D000613:Aminobutyrates / Q000032:analysis / Q000378:metabolism*; D002853:Chromatography, Liquid; D004305:Dose-Response Relationship, Drug; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D006540:Herbicides / Q000032:analysis / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000378:metabolism*; D014908:Triticum / Q000235:genetics / Q000378:metabolism*
chemical_list: D000613:Aminobutyrates; D006540:Herbicides; C003121:phosphinothricin; D005974:Glutamate-Ammonia Ligase
keywords: Degradation; GMO crops; Glufosinate; LC–DAD; LC–TOF/MS; Metabolism; Resistance; Triticum aestivum