title: A rhamnose-rich O-antigen mediates adhesion, virulence, and host colonization for the xylem-limited phytopathogen Xylella fastidiosa.
abstract: Xylella fastidiosa is a gram-negative, xylem-limited bacterium that causes a lethal disease of grapevine called Pierce's disease. Lipopolysaccharide (LPS) composes approximately 75% of the outer membrane of gram-negative bacteria and, because it is largely displayed on the cell surface, it mediates interactions between the bacterial cell and its surrounding environment. LPS is composed of a conserved lipid A-core oligosaccharide component and a variable O-antigen portion. By targeting a key O-antigen biosynthetic gene, we demonstrate the contribution of the rhamnose-rich O-antigen to surface attachment, cell-cell aggregation, and biofilm maturation: critical steps for successful infection of the host xylem tissue. Moreover, we have demonstrated that a fully formed O-antigen moiety is an important virulence factor for Pierce's disease development in grape and that depletion of the O-antigen compromises its ability to colonize the host. It has long been speculated that cell-surface polysaccharides play a role in X. fastidiosa virulence and this study confirms that LPS is a major virulence factor for this important agricultural pathogen.
authors: Department of Plant Pathology and Microbiology, University of California, Riverside, CA, USA.
authors: Jennifer C
authors: JC
authors: Clifford
authors: Jeannette N
authors: JN
authors: Rapicavoli
authors: M Caroline
authors: MC
authors: Roper
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000302:isolation & purification / Q000378:metabolism; D009154:Mutation; D019081:O Antigens / Q000302:isolation & purification / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology*; D017434:Protein Structure, Tertiary; D012210:Rhamnose / Q000378:metabolism; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000302:isolation & purification / Q000378:metabolism; D027843:Vitis / Q000382:microbiology*; D044167:Xylella / Q000187:drug effects / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology; D052584:Xylem / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D008070:Lipopolysaccharides; D019081:O Antigens; D037521:Virulence Factors; D006861:Hydrogen Peroxide; D012210:Rhamnose