title: The effect of cellulose overproduction on binding and biofilm formation on roots by Agrobacterium tumefaciens.
abstract: Agrobacterium tumefaciens growing in liquid attaches to the surface of tomato and Arabidopsis thaliana roots, forming a biofilm. The bacteria also colonize roots grown in sterile quartz sand. Attachment, root colonization, and biofilm formation all were markedly reduced in celA and chvB mutants, deficient in production of cellulose and cyclic beta-(1,2)-D-glucans, respectively. We have identified two genes (celG and cell) in which mutations result in the overproduction of cellulose as judged by chemical fractionation and methylation analysis. Wild-type and chvB mutant strains carrying a cDNA clone of a cellulose synthase gene from the marine urochordate Ciona savignyi also overproduced cellulose. The overproduction in a wild-type strain resulted in increased biofilm formation on roots, as evaluated by light microscopy, and levels of root colonization intermediate between those of cellulose-minus mutants and the wild type. Overproduction of cellulose by a nonattaching chvB mutant restored biofilm formation and bacterial attachment in microscopic and viable cell count assays and partially restored root colonization. Although attachment to plant surfaces was restored, overproduction of cellulose did not restore virulence in the chvB mutant strain, suggesting that simple bacterial binding to plant surfaces is not sufficient for pathogenesis.
authors.affiliation: University of North Carolina, Department of Biology, Chapel Hill 27599-3280, USA. ann_matthysse@unc.edu
authors.forename: Ann G
authors.initials: AG
authors.lastname: Matthysse
authors.forename: Mazz
authors.initials: M
authors.lastname: Marry
authors.forename: Leonard
authors.initials: L
authors.lastname: Krall
authors.forename: Mitchell
authors.initials: M
authors.lastname: Kaye
authors.forename: Bronwyn E
authors.initials: BE
authors.lastname: Ramey
authors.forename: Clay
authors.initials: C
authors.lastname: Fuqua
authors.forename: Alan R
authors.initials: AR
authors.lastname: White
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D000818:Animals; D001422:Bacterial Adhesion / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D018441:Biofilms / Q000254:growth & development*; D002480:Cellulase / Q000235:genetics / Q000378:metabolism; D002482:Cellulose / Q000096:biosynthesis* / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D005964:Glucosyltransferases / Q000235:genetics; D018551:Solanum lycopersicum / Q000382:microbiology; D009154:Mutation; D018517:Plant Roots / Q000382:microbiology; D010941:Plant Tumors / Q000382:microbiology; D014561:Urochordata / Q000201:enzymology / Q000235:genetics; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D002482:Cellulose; D005964:Glucosyltransferases; C478648:cellulose synthase; C081472:celG protein, Bacteria; D002480:Cellulase