title: Target-site mutations conferring resistance to glyphosate in feathertop Rhodes grass (Chloris virgata) populations in Australia.
abstract: BACKGROUND
  Chloris virgata is a warm-season, C4, annual grass weed affecting field crops in northern Australia that has become an emerging weed in southern Australia. Four populations with suspected resistance to glyphosate were collected in South Australia, Queensland and New South Wales, Australia, and compared with one susceptible (S) population to confirm glyphosate resistance and elucidate possible mechanisms of resistance.
  
  
  RESULTS
  Based on the rate of glyphosate required to kill 50% of treated plants (LD50), glyphosate resistance (GR) was confirmed in four populations of C. virgata (V12, V14.2, V14.16 and V15). GR plants were 2-9.7-fold more resistant and accumulated less shikimate after glyphosate treatment than S plants. GR and S plants did not differ in glyphosate absorption and translocation. Target-site EPSPS mutations corresponding to Pro-106-Leu (V14.2) and Pro-106-Ser (V15, V14.16 and V12) substitutions were found in GR populations. The population with Pro-106-Leu substitution was 2.9-4.9-fold more resistant than the three other populations with Pro-106-Ser substitution.
  
  
  CONCLUSIONS
  This report confirms glyphosate resistance in C. virgata and shows that target-site EPSPS mutations confer resistance to glyphosate in this species. The evolution of glyphosate resistance in C. virgata highlights the need to identify alternative control tactics. © 2016 Society of Chemical Industry.
authors.affiliation: School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, Adelaide, SA, Australia.
authors.forename: The D
authors.initials: TD
authors.lastname: Ngo
authors.affiliation: School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, Adelaide, SA, Australia.
authors.forename: Mahima
authors.initials: M
authors.lastname: Krishnan
authors.affiliation: School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, Adelaide, SA, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Boutsalis
authors.affiliation: School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, Adelaide, SA, Australia.
authors.forename: Gurjeet
authors.initials: G
authors.lastname: Gill
authors.affiliation: School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, Adelaide, SA, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Preston
mesh_terms: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase / Q000235:genetics; D001315:Australia; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D053209:Herbicide Resistance / Q000235:genetics*; D006540:Herbicides / Q000494:pharmacology*; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics; D006109:Poaceae / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D000097797:Glyphosate
chemical_list: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D005998:Glycine; D006540:Herbicides; D010940:Plant Proteins; D000097797:Glyphosate
keywords: Chloris virgata; EPSPS; glyphosate resistance; target-site mutation