PLoS ONE (Jan 2016)

EPSPS Gene Copy Number and Whole-Plant Glyphosate Resistance Level in Kochia scoparia.

  • Todd A Gaines,
  • Abigail L Barker,
  • Eric L Patterson,
  • Philip Westra,
  • Eric P Westra,
  • Robert G Wilson,
  • Prashant Jha,
  • Vipan Kumar,
  • Andrew R Kniss

DOI
https://doi.org/10.1371/journal.pone.0168295
Journal volume & issue
Vol. 11, no. 12
p. e0168295

Abstract

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Glyphosate-resistant (GR) Kochia scoparia has evolved in dryland chemical fallow systems throughout North America and the mechanism of resistance involves 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene duplication. Agricultural fields in four states were surveyed for K. scoparia in 2013 and tested for glyphosate-resistance level and EPSPS gene copy number. Glyphosate resistance was confirmed in K. scoparia populations collected from sugarbeet fields in Colorado, Wyoming, and Nebraska, and Montana. Glyphosate resistance was also confirmed in K. scoparia accessions collected from wheat-fallow fields in Montana. All GR samples had increased EPSPS gene copy number, with median population values up to 11 from sugarbeet fields and up to 13 in Montana wheat-fallow fields. The results indicate that glyphosate susceptibility can be accurately diagnosed using EPSPS gene copy number.