ISSN:
1432-2048
Keywords:
Daucus
;
Herbicide
;
Nicotina
;
Phosphinothricin-N-acetyl-transferase
;
Phosphinothricin metabolism
;
Transgenic plant
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract l-Phosphinothricin (l-Pt)-resistant plants were constructed by introducing a modified phosphinothricin-N-acetyl-transferase gene (pat) via Agrobacterium-mediated gene transfer into tobacco (Nicotiana tabacum L), and via direct gene transfer into carrot (Daucus carota L). The metabolism of l-Pt was studied in these transgenic, Pt-resistant plants, as well as in the untransformed species. The degradation of l-Pt, 14C-labeled specifically at different C-atoms, was analysed by measuring the release of 14CO2 and by separating the labeled degradation products on thin-layer-chromatography plates. In untransformed tobacco and carrot plants, l-Pt was deaminated to form its corresponding oxo acid 4-methylphosphinico-2-oxo-butanoic acid (PPO), which subsequently was decarboxylated to form 3-methylphosphinico-propanoic acid (MPP). This compound was stable in plants. A third metabolite remained unidentified. The l-Pt was rapidly N-acetylated in herbicide-resistant tobacco and carrot plants, indicating that the degradation pathway of l-Pt into PPO and MPP was blocked. The N-acetylated product, l-N-acetyl-Pt remained stable with regard to degradation, but was found to exist in a second modified form. In addition, there was a pH-dependent, reversible change in the mobility of l-N-acetyl-Pt thin-layer during chromatography.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00201636
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