title: The β-1,3-glucanosyltransferases (Gels) affect the structure of the rice blast fungal cell wall during appressorium-mediated plant infection.
abstract: The fungal wall is pivotal for cell shape and function, and in interfacial protection during host infection and environmental challenge. Here, we provide the first description of the carbohydrate composition and structure of the cell wall of the rice blast fungus Magnaporthe oryzae. We focus on the family of glucan elongation proteins (Gels) and characterize five putative β-1,3-glucan glucanosyltransferases that each carry the Glycoside Hydrolase 72 signature. We generated targeted deletion mutants of all Gel isoforms, that is, the GH72+, which carry a putative carbohydrate-binding module, and the GH72-Gels, without this motif. We reveal that M. oryzae GH72+GELs are expressed in spores and during both infective and vegetative growth, but each individual Gel enzymes are dispensable for pathogenicity. Further, we demonstrated that a Δgel1Δgel3Δgel4 null mutant has a modified cell wall in which 1,3-glucans have a higher degree of polymerization and are less branched than the wild-type strain. The mutant showed significant differences in global patterns of gene expression, a hyper-branching phenotype and no sporulation, and thus was unable to cause rice blast lesions (except via wounded tissues). We conclude that Gel proteins play significant roles in structural modification of the fungal cell wall during appressorium-mediated plant infection.
authors: Department of Plant Sciences, University of Oxford, Oxford, UK.
authors: Marketa
authors: M
authors: Samalova
authors: Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), Stockholm, Sweden.|Centre for Plant Biotechnology and Genomics, Universidad Politécnica de Madrid, Madrid, Spain.
authors: Hugo
authors: H
authors: Mélida
authors: Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), Stockholm, Sweden.
authors: Francisco
authors: F
authors: Vilaplana
authors: Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), Stockholm, Sweden.|ARC Centre of Excellence in Plant Cell Walls and School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, South Australia, Australia.
authors: Vincent
authors: V
authors: Bulone
authors: School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
authors: Darren M
authors: DM
authors: Soanes
authors: School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
authors: Nicholas J
authors: NJ
authors: Talbot
authors: Department of Plant Sciences, University of Oxford, Oxford, UK.|School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
authors: Sarah J
authors: SJ
authors: Gurr
mesh_terms: D002473:Cell Wall / Q000737:chemistry*; D017353:Gene Deletion; D004693:Glucan Endo-1,3-beta-D-Glucosidase / Q000235:genetics / Q000378:metabolism*; D020082:Magnaporthe / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D012275:Oryza / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D011509:Proteoglycans; D013172:Spores, Fungal / Q000201:enzymology / Q000378:metabolism; D047071:beta-Glucans / Q000032:analysis*
chemical_list: D011509:Proteoglycans; D047071:beta-Glucans; C010770:polysaccharide-K; C117939:1,3-beta-glucanosyltransferase; D004693:Glucan Endo-1,3-beta-D-Glucosidase