Biosynthesis of mono- and sesquiterpenes in carrot roots and leaves (Daucus carota L.): metabolic cross talk of cytosolic mevalonate and plastidial methylerythritol phosphate pathways

Phytochemistry. 2005 Feb;66(3):305-11. doi: 10.1016/j.phytochem.2004.12.010.

Abstract

The biosynthesis of the monoterpenes terpinolene and myrcene and the sesquiterpene beta-caryophyllene in roots and leaves of two carrot varieties (Daucus carota L. cultivars Bolero and Kazan) were investigated by in vivo feeding experiments with [5,5-2H2]-mevalonic acid lactone (d2-MVL) and [5,5-2H2]-1-deoxy-D-xylulose (d2-DOX). The volatiles of the tissues were extracted by stir bar sorptive extraction and analyzed using thermal desorption-multidimensional gas chromatography-mass spectrometry. The experiments demonstrate independent de novo-biosynthesis of terpenoids in carrot roots and in carrot leaves. In both plant tissues monoterpenes are biosynthesized exclusively via the 1-deoxy-D-xylulose/2-C-methyl-D-erythritol-4-phosphate (DOXP/MEP) pathway, whereas sesquiterpenes are generated by the classical mevalonic acid pathway as well as by the DOXP/MEP route. A more detailed investigation of carrot root tissues revealed that the biosynthesis of terpenes is mainly localized in the phloem. Nevertheless, in xylem a de novo-biosynthesis of terpenes was detectable as well, even in the absence of oil ducts in this tissue.

MeSH terms

  • Cytosol / metabolism
  • Daucus carota / chemistry
  • Daucus carota / cytology
  • Daucus carota / metabolism*
  • Erythritol / chemistry
  • Erythritol / metabolism*
  • Mass Spectrometry
  • Mevalonic Acid / chemistry
  • Mevalonic Acid / metabolism*
  • Monoterpenes / chemistry
  • Monoterpenes / metabolism*
  • Plant Leaves / chemistry
  • Plant Leaves / metabolism*
  • Plant Roots / chemistry
  • Plant Roots / metabolism*
  • Plastids / metabolism*
  • Sesquiterpenes / chemistry
  • Sesquiterpenes / metabolism*
  • Stereoisomerism

Substances

  • Monoterpenes
  • Sesquiterpenes
  • Erythritol
  • Mevalonic Acid