title: A red and far-red light receptor mutation confers resistance to the herbicide glyphosate.
abstract: Glyphosate is a widely applied broad-spectrum systemic herbicide that inhibits competitively the penultimate enzyme 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS) from the shikimate pathway, thereby causing deleterious effects. A glyphosate-resistant Arabidopsis mutant (gre1) was isolated and genetic analyses indicated that a dysfunctional red (R) and far-red (FR) light receptor, phytochrome B (phyB), caused this phenotype. This finding is consistent with increased glyphosate sensitivity and glyphosate-induced shikimate accumulation in low R:FR light, and the induction of genes encoding enzymes of the shikimate pathway in high R:FR light. Expression of the shikimate pathway genes exhibited diurnal oscillation and this oscillation was altered in the phyB mutant. Furthermore, transcript analysis suggested that this diurnal oscillation was not only dependent on phyB but was also due to circadian regulatory mechanisms. Our data offer an explanation of the well documented observation that glyphosate treatment at various times throughout the day, with their specific composition of light quality and intensity, results in different efficiencies of the herbicide.
authors.affiliation: Department of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Jeddah, Saudi Arabia; Department of Horticulture and Landscape Architecture, Purdue University, 47907, West Lafayette, Indiana, USA.
authors.forename: Altanbadralt
authors.initials: A
authors.lastname: Sharkhuu
authors.forename: Meena L
authors.initials: ML
authors.lastname: Narasimhan
authors.forename: Jasmeen S
authors.initials: JS
authors.lastname: Merzaban
authors.forename: Ray A
authors.initials: RA
authors.lastname: Bressan
authors.forename: Steve
authors.initials: S
authors.lastname: Weller
authors.forename: Chris
authors.initials: C
authors.lastname: Gehring
mesh_terms: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase / Q000037:antagonists & inhibitors; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002940:Circadian Rhythm; D004252:DNA Mutational Analysis; D005998:Glycine / Q000031:analogs & derivatives / Q000633:toxicity; D053209:Herbicide Resistance / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D055519:Photoreceptors, Plant / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D051939:Phytochrome B / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D000097797:Glyphosate
chemical_list: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D029681:Arabidopsis Proteins; D005998:Glycine; D055519:Photoreceptors, Plant; D051939:Phytochrome B; D000097797:Glyphosate
keywords: Arabidopsis thaliana; circadian rhythm; glyphosate; herbicide resistance; phyB; shikimate pathway