Free access article

Issue Environ. Biosafety Res. Volume 1, Number 1, October 2002 Page(s) 29 - 37 DOI 10.1051/ebr:2002003

Environ. Biosafety Res. 1 (2002) 29-37
DOI: 10.1051/ebr:2002003

A comparative investigation of the metabolism of the herbicide glufosinate in cell cultures of transgenic glufosinate-resistant and non-transgenic oilseed rape (Brassica napus) and corn (Zea mays)

Monika Ruhland¹, Gabriele Engelhardt¹ and Karlheinz Pawlizki<sup>2

1</sup>  Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Außenstelle München, Menzinger Straße 54, 80638 München, Germany
²  Bayerische Landesanstalt für Bodenkultur und Pflanzenbau, Menzinger Straße 54, 80638 München, Germany

Abstract
To obtain information on differences between the metabolic pathways of the herbicide glufosinate (trade names: BASTA®, LIBERTY®) in non-transgenic, glufosinate-sensitive plants and in transgenic, glufosinate-resistant plants, the metabolism of ¹⁴C-labeled glufosinate and its enantiomers L- and D-glufosinate was studied using cell cultures of oilseed rape and corn. Transformation of glufosinate in both sensitive and transgenic rape cells remained at a low rate of about 3-10% in contrast to corn cells, where 20% was transformed in sensitive and 43% in transgenic cells after 14 days of incubation, the rest remaining as unchanged glufosinate. In sensitive rape and corn cells the main metabolite was 4-methylphosphinico-2-oxo-butanoic acid (PPO) with 7.3 and 16.4%, respectively, together with low amounts of 3-methylphosphinicopropionic acid (MPP), 4-methylphosphinico-2-hydroxybutanoic acid (MHB), 4-methylphosphinicobutanoic acid (MPB) and 2-methylphosphinicoacetic acid (MPA). An additional metabolite formed in transgenic cell cultures was 2-acetamido-4-methylbutanoic acid (N-acetyl-L-glufosinate, NGA), which was formed at rates of 3.2% in rape and 16.1% in corn. A further minor metabolite, not yet identified, was detected in both cell types. The liberation of 0.2% ¹⁴CO ₂ indicates further metabolic steps prior to a limited mineralization in plant cell cultures. L-glufosinate was transformed into the same metabolites as the glufosinate racemate. D-glufosinate was not metabolized.

Key words: glufosinate / herbicide resistance / metabolism / phosphinothricin / transgenic plants / cell cultures

Correspondence and reprints: Gabriele Engelhardt Tel.: (49) 89 17 80 02 14; fax: (49) 89 17 80 01 70;
    e-mail: gabriele.engelhardt@lfe.bayern.de

© ISBR, EDP Sciences 2002

What is OpenURL?