Showing papers by "Fang Chen published in 1999"
TL;DR: In this article, a deuterium-labeled precursor was fed to stems of Magnolia kobus and the incorporation of the labeled precursor into lignin was traced by gas chromatography-mass spectrometry.
Abstract: The biosynthetic pathways to monolignols in Magnolia kobus were investigated by feeding stems with a deuterium-labeled precursor. Pentadeutero [γ,γ-2H2, OC2H3] coniferyl alcohol was supplied to shoots of Magnolia kobus and the incorporation of the labeled precursor into lignin was traced by gas chromatography-mass spectrometry. In addition to the direct incorporation of the labeled precursor into guaiacyl units, we detected a significant amount of pentadeuterium-labeled syringyl units with two γ-deuterium atoms. The relative level of trideuterium-labeled syringyl monomers (the result of conversion via the cinnamic acid pathway, in which two γ-deuterium atoms are removed during enzymatic re-oxidation) was negligible. Our results provide conclusive evidence for a novel alternative pathway for generation of lignin subunits at the monolignol stage and they suggest that this new pathway might be important for regulation of the composition of lignin.
81 citations
TL;DR: In this paper, the lignin biosynthetic pathway in Eucalyptus camaldulensis was investigated by feeding stems with deuterium-labeled precursor.
Abstract: The lignin biosynthetic pathway in Eucalyptus camaldulensis was investigated by feeding stems with deuterium-labeled precursor. Pentadeutero[γ,γ-D2 OCD3] coniferyl alcohol was synthesized and supplied to shoots of E. camaldulensis, and incorporation of the labeled precursor into lignin was traced by gas chromatography-mass spectrometry. In addition to the direct incorporation of labeled precursor into the guaiacyl unit, a pentadeuterium-labeled syringyl unit was detected. This finding indicates that the γ-deuterium atoms in the hydroxymethyl group of labeled coniferyl alcohol remain intact during modification of the aromatic ring. The relative level of trideuterium-labeled syringyl monomer (the result of conversion via the cinnamic acid pathway) was negligible, suggesting that the pathway at the monolignol stage is used for conversion of exogenously supplied precursor. Our results provide conclusive evidence of a novel alternative pathway for generation of lignin subunits at the monolignol stage even in plants that do not accumulate coniferin in lignifying tissues.
8 citations
01 Jan 1999
TL;DR: In this article, a deuterium-labeled precursor was fed to stems of Magnolia kobus and the incorporation of the labeled precursor into lignin was traced by gas chromatography mass spectrometry.
Abstract: The biosynthetic pathways to monolignols in Magnolia kobus were investigated by feeding stems with a deuterium-labeled precursor. Pentadeutero (y,y-2H2, OC2H3) coniferyl alcohol was supplied to shoots of Magnolia kobus and the incorporation of the labeled precursor into lignin was traced by gas chromatography mass spectrometry. In addition to the direct incorpora tion of the labeled precursor into guaiacyl units, we detected a significant amount of pentadeuterium-labeled syringyl units with two y-deuterium atoms. The relative level of trideuterium-labeled syringyl monomers (the result of conversion via the cinnamic acid pathway, in which two y-deuterium atoms are removed during enzymatic re-oxidation) was negligible. Our results provide conclusive evidence for a novel alternative pathway for generation of lignin subunits at the mono lignol stage and they suggest that this new pathway might be important for regulation of the composition of lignin.