Mutants in DEFECTIVE GLYCOSYLATION, an Arabidopsis homolog of an oligosaccharyltransferase complex subunit, show protein underglycosylation and defects in cell differentiation and growth

Plant J. 2005 May;42(4):455-68. doi: 10.1111/j.1365-313X.2005.02392.x.


A mutant called defective glycosylation1-1 (dgl1-1) was identified in Arabidopsis based on a growth defect of the dark-grown hypocotyl and an abnormal composition of the non-cellulosic cell wall polysaccharides. dgl1-1 is altered in a protein ortholog of human OST48 or yeast WBP1, an essential protein subunit of the oligosaccharyltransferase (OST) complex, which is responsible for the transfer in the ER of the N-linked glycan precursor onto Asn residues of candidate proteins. Consistent with the known function of the OST complex in eukaryotes, the dgl1-1 mutation led to a reduced N-linked glycosylation of the ER-resident protein disulfide isomerase. A second more severe mutant (dgl1-2) was embryo-lethal. Microscopic analysis of dgl1-1 revealed developmental defects including reduced cell elongation and the collapse and differentiation defects of cells in the central cylinder. These defects were accompanied by changes in the non-cellulosic polysaccharide composition, including the accumulation of ectopic callose. Interestingly, in contrast to other dwarf mutants that are altered in early steps of the N-glycan processing, dgl1-1 did not exhibit a cellulose deficiency. Together, these results confirm the role of DGL1 in N-linked glycosylation, cell growth and differentiation in plants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / cytology
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cell Differentiation / genetics
  • Cell Differentiation / physiology*
  • Cell Wall
  • Gene Expression
  • Glycosylation
  • Hexosyltransferases / genetics
  • Hexosyltransferases / metabolism*
  • Hypocotyl / ultrastructure
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Mutation
  • Phenotype
  • Plant Roots / ultrastructure
  • Plants, Genetically Modified
  • Sequence Homology, Amino Acid


  • Arabidopsis Proteins
  • DGL1 protein, Arabidopsis
  • Membrane Proteins
  • Hexosyltransferases
  • dolichyl-diphosphooligosaccharide - protein glycotransferase

Associated data

  • GENBANK/AAH02594
  • GENBANK/AAM63023
  • GENBANK/BAC82967
  • GENBANK/CAA43660