title: Evolution of a double amino acid substitution in the 5-enolpyruvylshikimate-3-phosphate synthase in Eleusine indica conferring high-level glyphosate resistance.
abstract: Glyphosate is the most important and widely used herbicide in world agriculture. Intensive glyphosate selection has resulted in the widespread evolution of glyphosate-resistant weed populations, threatening the sustainability of this valuable once-in-a-century agrochemical. Field-evolved glyphosate resistance due to known resistance mechanisms is generally low to modest. Here, working with a highly glyphosate-resistant Eleusine indica population, we identified a double amino acid substitution (T102I+P106S [TIPS]) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene in glyphosate-resistant individuals. This TIPS mutation recreates the biotechnology-engineered commercial first generation glyphosate-tolerant EPSPS in corn (Zea mays) and now in other crops. In E. indica, the naturally evolved TIPS mutants are highly (more than 180-fold) resistant to glyphosate compared with the wild type and more resistant (more than 32-fold) than the previously known P106S mutants. The E. indica TIPS EPSPS showed very high-level (2,647-fold) in vitro resistance to glyphosate relative to the wild type and is more resistant (600-fold) than the P106S variant. The evolution of the TIPS mutation in crop fields under glyphosate selection is likely a sequential event, with the P106S mutation being selected first and fixed, followed by the T102I mutation to create the highly resistant TIPS EPSPS. The sequential evolution of the TIPS mutation endowing high-level glyphosate resistance is an important mechanism by which plants adapt to intense herbicide selection and a dramatic example of evolution in action.
authors.affiliation: Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, Western Australia 6009, Australia (Q.Y., A.J., H.H., S.B.P.); andMonsanto Company, St. Louis, Missouri 63167 (M.C., R.D.S.).
authors.forename: Qin
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, Western Australia 6009, Australia (Q.Y., A.J., H.H., S.B.P.); andMonsanto Company, St. Louis, Missouri 63167 (M.C., R.D.S.).
authors.forename: Adam
authors.initials: A
authors.lastname: Jalaludin
authors.affiliation: Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, Western Australia 6009, Australia (Q.Y., A.J., H.H., S.B.P.); andMonsanto Company, St. Louis, Missouri 63167 (M.C., R.D.S.).
authors.forename: Heping
authors.initials: H
authors.lastname: Han
authors.affiliation: Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, Western Australia 6009, Australia (Q.Y., A.J., H.H., S.B.P.); andMonsanto Company, St. Louis, Missouri 63167 (M.C., R.D.S.).
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
authors.affiliation: Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, Western Australia 6009, Australia (Q.Y., A.J., H.H., S.B.P.); andMonsanto Company, St. Louis, Missouri 63167 (M.C., R.D.S.).
authors.forename: R Douglas
authors.initials: RD
authors.lastname: Sammons
authors.affiliation: Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, Western Australia 6009, Australia (Q.Y., A.J., H.H., S.B.P.); andMonsanto Company, St. Louis, Missouri 63167 (M.C., R.D.S.) stephen.powles@uwa.edu.au.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Powles
mesh_terms: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase / Q000235:genetics* / Q000378:metabolism; D019943:Amino Acid Substitution; D005075:Biological Evolution; D031748:Eleusine / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D053209:Herbicide Resistance / Q000235:genetics*; D006540:Herbicides / Q000494:pharmacology*; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D000097797:Glyphosate
chemical_list: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D005998:Glycine; D006540:Herbicides; D010940:Plant Proteins; D000097797:Glyphosate