title: Sugar-mediated induction of Agrobacterium tumefaciens virulence genes: structural specificity and activities of monosaccharides.
abstract: The virulence genes of Agrobacterium tumefaciens are induced by specific plant phenolic metabolites and sugars (G. A. Cangelosi, R. G. Ankenbauer, and E. W. Nester, Proc. Natl. Acad. Sci. USA, in press). In this report, monosaccharides, derivatives, and analogs which induce the vir regulon have been identified and the structural requirements for monosaccharide-mediated induction have been determined. Pyranose sugars with equatorial hydroxyls at C-1, C-2, and C-3 displayed strong vir gene-inducing activity; the C-4 hydroxyl could be epimeric and a wide variety of substitutions at C-5 were permissible. The acidic monosaccharide derivatives D-galacturonic acid and D-glucuronic acid were the strongest inducers among the monosaccharides tested. Eight of the 11 inducing compounds are known plant metabolites, and 7 are monomers of major plant cell wall polysaccharides. A role for monosaccharides and plant phenolic compounds as wound-specific plant metabolites which signal the ChvE/VirA/VirG regulatory system is proposed.
authors.affiliation: Department of Microbiology, University of Washington, Seattle 98195.
authors.forename: R G
authors.initials: RG
authors.lastname: Ankenbauer
authors.forename: E W
authors.initials: EW
authors.lastname: Nester
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D005798:Genes, Bacterial / Q000187:drug effects; D009005:Monosaccharides / Q000494:pharmacology*; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012231:Rhizobium / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity; D013329:Structure-Activity Relationship; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D009005:Monosaccharides; D011993:Recombinant Fusion Proteins; D037521:Virulence Factors; D001616:beta-Galactosidase