title: Target and Non-target Site Mechanisms Developed by Glyphosate-Resistant Hairy beggarticks (Bidens pilosaL.) Populations from Mexico.
abstract: In 2014 hairy beggarticks (Bidens pilosaL.) has been identified as being glyphosate-resistant in citrus orchards from Mexico. The target and non-target site mechanisms involved in the response to glyphosate of two resistant populations (R1 and R2) and one susceptible (S) were studied. Experiments of dose-response, shikimic acid accumulation, uptake-translocation, enzyme activity and 5-enolpyruvyl shikimate-3-phosphate synthase (EPSPS) gene sequencing were carried out in each population. The R1 and R2 populations were 20.4 and 2.8-fold less glyphosate sensitive, respectively, than the S population. The resistant populations showed a lesser shikimic acid accumulation than the S population. In the latter one, 24.9% of14C-glyphosate was translocated to the roots at 96 h after treatment; in the R1 and R2 populations only 12.9 and 15.5%, respectively, was translocated. Qualitative results confirmed the reduced14C-glyphosate translocation in the resistant populations. The EPSPS enzyme activity of the S population was 128.4 and 8.5-fold higher than the R1 and R2 populations of glyphosate-treated plants, respectively. A single (Pro-106-Ser), and a double (Thr-102-Ile followed by Pro-106-Ser) mutations were identified in the EPSPS2 gene conferred high resistance in R1 population. Target-site mutations associated with a reduced translocation were responsible for the higher glyphosate resistance in the R1 population. The low-intermediate resistance of the R2 population was mediated by reduced translocation. This is the first glyphosate resistance case confirmed in hairy beggarticks in the world.
authors.affiliation: Department of Agricultural Chemistry and Edaphology, Campus of Rabanales, University of CordobaCordoba, Spain; Department of Agricultural Parasitology, Chapingo Autonomous UniversityTexcoco, Mexico.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Alcántara-de la Cruz
authors.affiliation: Department of Agricultural Chemistry and Edaphology, Campus of Rabanales, University of Cordoba Cordoba, Spain.
authors.forename: Pablo T
authors.initials: PT
authors.lastname: Fernández-Moreno
authors.affiliation: Institute for Sustainable Agriculture, Spanish National Research Council Cordoba, Spain.
authors.forename: Carmen V
authors.initials: CV
authors.lastname: Ozuna
authors.affiliation: Department of Agricultural Chemistry and Edaphology, Campus of Rabanales, University of Cordoba Cordoba, Spain.
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Rojano-Delgado
authors.affiliation: Bayer CropScience Mexico Mexico, Mexico.
authors.forename: Hugo E
authors.initials: HE
authors.lastname: Cruz-Hipolito
authors.affiliation: Department of Agricultural Parasitology, Chapingo Autonomous University Texcoco, Mexico.
authors.forename: José A
authors.initials: JA
authors.lastname: Domínguez-Valenzuela
authors.affiliation: Institute for Sustainable Agriculture, Spanish National Research Council Cordoba, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Barro
authors.affiliation: Department of Agricultural Chemistry and Edaphology, Campus of Rabanales, University of Cordoba Cordoba, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: De Prado
keywords: 5-enolpyruvyl shikimate-3-phosphate synthase; Bidens pilosa; EPSPS2; TIPS mutation; glyphosate translocation; resistance mechanisms