Identification of Arabidopsis thaliana variants with differential glyphosate responses

approaches were taken to obtain Arabidopsis thaliana variants that differed in glyphosate response. Recurrent selection by spraying with sub-lethal glyphosate concentrations was performed with Columbia-0 seedlings. After seven cycles of treatment, no resistance was found. A population of 800,000 ethylmethanesulfonate-mutagenized M-2 seedlings was screened on agar containing 0.2 mM glyphosate, a lower concentration than that previously used in other studies, and no resistant mutants were recovered. Seventy-two Arabidopsis ecotypes were screened with glyphosate and a range of responses was observed. In a follow-up experiment on a subset of these ecotypes, reduction of seed yield by 11.5 g/ha glyphosate (about 11% the typical field use rate) ranged among ecotypes from 0% to >90%, relative to untreated controls. However, even the least sensitive ecotypes were severely injured by relatively tow gtyphosate rates. Overall, attempts to select Arabidopsis seedlings that were significantly glyphosate-resistant were unsuccessful and consistent with previous reports. Arabidopsis ecotypes identified with differential gtyphosate responses could be used for further studies though the inherently high sensitivity of Arabidopsis to gtyphosate could limit their utility in studying glyphosate-resistance mechanisms. (C) 2006 Elsevier GrnbH. All rights reserved.