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.
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Received: 21 August 1998 / Accepted: 30 September 1998
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Chen, F., Yasuda, S. & Fukushima, K. Evidence for a novel biosynthetic pathway that regulates the ratio of syringyl to guaiacyl residues in lignin in the differentiating xylem of Magnolia kobus DC. Planta 207, 597–603 (1999). https://doi.org/10.1007/s004250050523
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DOI: https://doi.org/10.1007/s004250050523