title: Protein O-linked glycosylation in the plant pathogen Ralstonia solanacearum.
abstract: Ralstonia solanacearum is one of the most lethal phytopathogens in the world. Due to its broad host range, it can cause wilting disease in many plant species of economic interest. In this work, we identified the O-oligosaccharyltransferase (O-OTase) responsible for protein O-glycosylation in R. solanacearum. An analysis of the glycoproteome revealed that 20 proteins, including type IV pilins are substrates of this general glycosylation system. Although multiple glycan forms were identified, the majority of the glycopeptides were modified with a pentasaccharide composed of HexNAc-(Pen)-dHex(3), similar to the O antigen subunit present in the lipopolysaccharide of multiple R. solanacearum strains. Disruption of the O-OTase led to the total loss of protein glycosylation, together with a defect in biofilm formation and reduced pathogenicity towards tomato plants. Comparative proteomic analysis revealed that the loss of glycosylation is not associated with widespread proteome changes. Only the levels of a single glycoprotein, the type IV pilin, were diminished in the absence of glycosylation. In parallel, disruption of glycosylation triggered an increase in the levels of a surface lectin homologous to Pseudomonas PA-IIL. These results reveal the important role of glycosylation in the pathogenesis of R. solanacearum.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: Wael
authors.initials: W
authors.lastname: Elhenawy
authors.affiliation: Centre for High-Throughput Biology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Nichollas E
authors.initials: NE
authors.lastname: Scott
authors.affiliation: Facultad de Ciencias Bioquímicas y Farmacéuticas (FBIOYF-UNR), Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Rosario, Santa Fe, Argentina.
authors.forename: M Laura
authors.initials: ML
authors.lastname: Tondo
authors.affiliation: Facultad de Ciencias Bioquímicas y Farmacéuticas (FBIOYF-UNR), Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Rosario, Santa Fe, Argentina.
authors.forename: Elena G
authors.initials: EG
authors.lastname: Orellano
authors.affiliation: Centre for High-Throughput Biology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Leonard J
authors.initials: LJ
authors.lastname: Foster
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada Department of Molecular Microbiology, Washington University School of Medicine St. Louis, St. Louis, MO, USA mariofeldman@wustl.edu.
authors.forename: Mario F
authors.initials: MF
authors.lastname: Feldman
mesh_terms: D036781:Fimbriae Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D006023:Glycoproteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D006031:Glycosylation; D006602:Hexosyltransferases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D018551:Solanum lycopersicum / Q000201:enzymology / Q000382:microbiology; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D019081:O Antigens / Q000737:chemistry / Q000235:genetics; D040901:Proteomics; D043368:Ralstonia solanacearum / Q000737:chemistry* / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D008565:Membrane Proteins; D019081:O Antigens; D036781:Fimbriae Proteins; D006602:Hexosyltransferases; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase
keywords: Type IV pili; biofilm; protein O-glycosylation