title: Elucidation of the biosynthetic pathway of the allelochemical sorgoleone using retrobiosynthetic NMR analysis.
abstract: NMR analyses of the labeling pattern obtained using various 13C-labeled precursors indicated that both the lipid tail and the quinone head of sorgoleone, the main allelopathic component of the oily root exudate of Sorghum bicolor, were derived from acetate units, but that the two moieties were synthesized in different subcellular compartments. The 16:3 fatty acid precursor of the tail is synthesized by the combined action of fatty-acid synthase and desaturases most likely in the plastids. It is then exported out of the plastids and converted to 5-pentadecatriene resorcinol by a polyketide synthase. This resorcinol intermediate was identified in root hair extracts. The lipid resorcinol intermediate is then methylated by a S-adenosylmethionine-dependent O-methyltransferase and subsequently dihydroxylated by a P450 monooxygenase to yield the reduced form of sorgoleone.
authors.affiliation: United States Department of Agriculture/Agricultural Research Service, Natural Products Utilization Research Unit, University, Mississippi 38677, USA. fdayan@ars.usda.gov
authors.forename: Franck E
authors.initials: FE
authors.lastname: Dayan
authors.forename: Isabelle A
authors.initials: IA
authors.lastname: Kagan
authors.forename: Agnes M
authors.initials: AM
authors.lastname: Rimando
mesh_terms: D016227:Benzoquinones / Q000737:chemistry / Q000378:metabolism*; D002247:Carbon Isotopes; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D002523:Edible Grain / Q000737:chemistry; D044943:Fatty Acid Desaturases / Q000378:metabolism; D064429:Fatty Acid Synthases / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D015394:Molecular Structure; D010936:Plant Extracts; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D011497:Protein O-Methyltransferase / Q000378:metabolism; D011809:Quinones / Q000378:metabolism; D012118:Resorcinols / Q000032:analysis / Q000378:metabolism
chemical_list: D016227:Benzoquinones; D002247:Carbon Isotopes; D008055:Lipids; D010936:Plant Extracts; D011809:Quinones; D012118:Resorcinols; C113738:sorgoleone; D003577:Cytochrome P-450 Enzyme System; D044943:Fatty Acid Desaturases; D011497:Protein O-Methyltransferase; D064429:Fatty Acid Synthases; C031389:resorcinol