The biosynthesis of allelopathic di-C-glycosylflavones from the roots of Desmodium incanum (G. Mey.) DCElectronic supplementary information (ESI) available. See DOI: 10.1039/c5ob01926e

• Main Authors: Hao, Bing, Caulfield, John C, Hamilton, Mary L, Pickett, John A, Midega, Charles A. O, Khan, Zeyaur R, Wang, Junru R, Hooper, Antony M
• Format: Journal Article
• Language: English
• Published: 01.12.2015
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c5ob01926e

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. Biosynthesis of allelopathic di- C -glycosylflavones in the plant D. incanum , occurs by UDP-glucosylation of a natural or analogue 2-hydroxyflavonoid substrate, followed by a second glycosylation with UDP-Glu, UDP-Ara, or UDP-Gal.