title: The Fusarium oxysporum gnt2, encoding a putative N-acetylglucosamine transferase, is involved in cell wall architecture and virulence.
abstract: With the aim to decipher the molecular dialogue and cross talk between Fusarium oxysporum f.sp. lycopersci and its host during infection and to understand the molecular bases that govern fungal pathogenicity, we analysed genes presumably encoding N-acetylglucosaminyl transferases, involved in glycosylation of glycoproteins, glycolipids, proteoglycans or small molecule acceptors in other microorganisms. In silico analysis revealed the existence of seven putative N-glycosyl transferase encoding genes (named gnt) in F. oxysporum f.sp. lycopersici genome. gnt2 deletion mutants showed a dramatic reduction in virulence on both plant and animal hosts. Δgnt2 mutants had αalterations in cell wall properties related to terminal αor β-linked N-acetyl glucosamine. Mutant conidia and germlings also showed differences in structure and physicochemical surface properties. Conidial and hyphal aggregation differed between the mutant and wild type strains, in a pH independent manner. Transmission electron micrographs of germlings showed strong cell-to-cell adherence and the presence of an extracellular chemical matrix. Δgnt2 cell walls presented a significant reduction in N-linked oligosaccharides, suggesting the involvement of Gnt2 in N-glycosylation of cell wall proteins. Gnt2 was localized in Golgi-like sub-cellular compartments as determined by fluorescence microscopy of GFP::Gnt2 fusion protein after treatment with the antibiotic brefeldin A or by staining with fluorescent sphingolipid BODIPY-TR ceramide. Furthermore, density gradient ultracentrifugation allowed co-localization of GFP::Gnt2 fusion protein and Vps10p in subcellular fractions enriched in Golgi specific enzymatic activities. Our results suggest that N-acetylglucosaminyl transferases are key components for cell wall structure and influence interactions of F. oxysporum with both plant and animal hosts during pathogenicity.
authors.affiliation: Departamento de Genética, Universidad de Córdoba, Córdoba, Spain ; Campus de Excelencia Agroalimentario (ceiA3), Córdoba, Spain.
authors.forename: Loida
authors.initials: L
authors.lastname: López-Fernández
authors.affiliation: Departamento de Genética, Universidad de Córdoba, Córdoba, Spain ; Campus de Excelencia Agroalimentario (ceiA3), Córdoba, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Ruiz-Roldán
authors.affiliation: Departamento de Genética, Universidad de Córdoba, Córdoba, Spain ; Campus de Excelencia Agroalimentario (ceiA3), Córdoba, Spain.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Pareja-Jaime
authors.affiliation: Centro de Investigaciones Biológicas-CSIC, Madrid, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Prieto
authors.affiliation: Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Córdoba, Spain.
authors.forename: Husam
authors.initials: H
authors.lastname: Khraiwesh
authors.affiliation: Departamento de Genética, Universidad de Córdoba, Córdoba, Spain ; Campus de Excelencia Agroalimentario (ceiA3), Córdoba, Spain.
authors.forename: M Isabel G
authors.initials: MI
authors.lastname: Roncero
mesh_terms: D000423:Alcian Blue; D002448:Cell Adhesion / Q000502:physiology; D002458:Cell Fractionation; D002473:Cell Wall / Q000201:enzymology* / Q000648:ultrastructure; D003001:Cloning, Molecular; D019295:Computational Biology; D005109:Extracellular Matrix / Q000648:ultrastructure; D005434:Flow Cytometry; D005670:Fusarium / Q000201:enzymology* / Q000472:pathogenicity*; D005800:Genes, Fungal / Q000235:genetics*; D006031:Glycosylation; D016013:Likelihood Functions; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics* / Q000378:metabolism*; D009841:Oligonucleotides / Q000235:genetics; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D014461:Ultracentrifugation; D014774:Virulence
chemical_list: D009841:Oligonucleotides; D017351:N-Acetylglucosaminyltransferases; D000423:Alcian Blue