Biosynthesis of galactomannans found in filamentous fungi belonging to Pezizomycotina

Biosci Biotechnol Biochem. 2018 Feb;82(2):183-191. doi: 10.1080/09168451.2017.1422383. Epub 2018 Jan 15.

Abstract

The galactomannans (GMs) that are produced by filamentous fungi belonging to Pezizomycotina, many of which are pathogenic for animals and plants, are polysaccharides consisting of α-(1→2)-/α-(1→6)-mannosyl and β-(1→5)-/β-(1→6)-galactofuranosyl residues. GMs are located at the outermost layer of the cell wall. When a pathogenic fungus infects a host, its cell surface must be in contact with the host. The GMs on the cell surface may be involved in the infection mechanism of a pathogenic fungus or the defense mechanism of a host. There are two types of GMs in filamentous fungi, fungal-type galactomannans and O-mannose type galactomannans. Recent biochemical and genetic advances have facilitated a better understanding of the biosynthesis of both types. This review summarizes our current information on their biosynthesis.

Keywords: 6xHis: 6xhistidine; Aspergillus; CAZy: Carbohydrate-Active enZYmes Database; ER: endoplasmic reticulum; FTGM: fungal-type galactomannan; GM: galactomannan; GMPs: galactomannoproteins; GPI: glycosylphosphatidylinositol; GT family: glycosyltransferase family; Galactofuranose; Galf: D-galactofuranose; Galp: D-galactopyranose; Man: mannose; OMGM: O-mannose type galactomannan; Pmt: protein-O-D-mannosyltransferase; UDP: uridine 5′-diphosphate; WT: wild-type; cell wall; eGFP: enhanced green fluorescent protein; filamentous fungi; galactomannan; mRFP: monomer red fluorescent protein; pNP β-Galf: p-nitrophenyl β-D-galactofuranoside.

Publication types

  • Review

MeSH terms

  • Ascomycota / metabolism*
  • Carbohydrate Sequence
  • Fungal Proteins / metabolism
  • Galactose / analogs & derivatives
  • Mannans / biosynthesis*
  • Mannans / chemistry
  • Protein Transport

Substances

  • Fungal Proteins
  • Mannans
  • galactomannan
  • Galactose