title: The biosynthesis of allelopathic di-C-glycosylflavones from the roots of Desmodium incanum (G. Mey.) DC.
abstract: The allelopathic root exudate of the drought-tolerant subsistence cereal intercrop D. incanum, protecting against the parasitic weed Striga hermonthica, comprises a number of di-C-glycosylflavones specifically containing C-glucosyl, C-galactosyl and C-arabinosyl moieties. Here we demonstrate that the biosynthesis of all compounds containing a C-glucose involves C-glucosylation of 2-hydroxynaringenin with subsequent C-galactosylation, C-glucosylation or C-arabinosylation. In addition, the crude soluble enzyme extract converts two fluorinated 2-hydroxyflavanone analogues to corresponding mono- and di-C-glycosylflavones demonstrating that some differences in C-ring substitution can be tolerated by the plant enzymes. Elucidating the biosynthesis of these C-glycosylflavones (CGFs) has the potential to open up opportunities for transferring the enzymic and genetic basis for the S. hermonthica inhibiting allelopathic trait to food crop plants.
authors.affiliation: College of Science, Northwest A&F University, Yangling, Shaanxi 712100, China. bing.hao@rothamsted.ac.uk.
authors.forename: Bing
authors.initials: B
authors.lastname: Hao
authors.forename: John C
authors.initials: JC
authors.lastname: Caulfield
authors.forename: Mary L
authors.initials: ML
authors.lastname: Hamilton
authors.forename: John A
authors.initials: JA
authors.lastname: Pickett
authors.forename: Charles A O
authors.initials: CA
authors.lastname: Midega
authors.forename: Zeyaur R
authors.initials: ZR
authors.lastname: Khan
authors.forename: Junru R
authors.initials: JR
authors.lastname: Wang
authors.forename: Antony M
authors.initials: AM
authors.lastname: Hooper
mesh_terms: D064089:Allelopathy; D007887:Fabaceae / Q000737:chemistry*; D047309:Flavones / Q000096:biosynthesis* / Q000737:chemistry*; D006031:Glycosylation; D015394:Molecular Structure; D018517:Plant Roots / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D047309:Flavones; C043562:flavone