title: Defects in D-rhamnosyl residue biosynthetic genes affect lipopolysaccharide structure, motility, and cell-surface hydrophobicity in Pseudomonas syringae pathovar glycinea race 4.
abstract: D-rhamnose (D-Rha) residue is a major component of lipopolysaccharides (LPSs) in strains of the phytopathogen Pseudomonas syringae pathovar glycinea. To investigate the effects of a deficiency in GDP-D-rhamnose biosynthetic genes on LPS structure and pathogenicity, we generated three mutants defective in D-Rha biosynthetic genes, encoding proteins GDP-D-mannose 4,6-dehydratase (GMD), GDP-4-keto-6-deoxy-D-mannose reductase (RMD), and a putative α-D-rhamnosyltransferase (WbpZ) in P. syringae pv. glycinea race 4. The Δgmd, Δrmd, and ΔwbpZ mutants had a reduced O-antigen polysaccharide consisting of D-Rha residues as compared with the wild type (WT). The swarming motility of the Δgmd, Δrmd, and ΔwbpZ mutant strains decreased and hydrophobicity and adhesion ability increased as compared with WT. Although the mutants had truncated O-antigen polysaccharides, and altered surface properties, they showed virulence to soybean, as WT did.
authors.affiliation: National Food Research Institute, Tsukuba, Ibaraki, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiku
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tsunemi
authors.forename: Masanobu
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Mayumi
authors.initials: M
authors.lastname: Ohnishi-Kameyama
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Yoshida
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ishii
authors.forename: Fumiko
authors.initials: F
authors.lastname: Taguchi
authors.forename: Masako
authors.initials: M
authors.lastname: Iwaki
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ichinose
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ono
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion; D005798:Genes, Bacterial / Q000235:genetics; D006156:Guanosine Diphosphate Sugars / Q000096:biosynthesis; D057927:Hydrophobic and Hydrophilic Interactions; D009068:Movement; D009154:Mutation; D019081:O Antigens / Q000737:chemistry* / Q000378:metabolism*; D011134:Polysaccharides / Q000032:analysis; D044224:Pseudomonas syringae / Q000166:cytology* / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D012210:Rhamnose / Q000096:biosynthesis*
chemical_list: D000900:Anti-Bacterial Agents; C422949:GDP-rhamnose; D006156:Guanosine Diphosphate Sugars; D019081:O Antigens; D011134:Polysaccharides; D012210:Rhamnose