A Missense Mutation in the Transmembrane Domain of CESA4 Affects Protein Abundance in the Plasma Membrane and Results in Abnormal Cell Wall Biosynthesis in Rice

Plant Mol Biol. 2009 Nov;71(4-5):509-24. doi: 10.1007/s11103-009-9536-4. Epub 2009 Aug 21.

Abstract

Cellulose synthase (CESA) is a critical catalytic subunit of the cellulose synthase complex responsible for glucan chain elongation. Our knowledge about how CESA functions is still very limited. Here, we report the functional characterization of a rice mutant, brittle culm11, that shows growth retardation and dramatically reduced plant strength. Map-based cloning revealed that all the mutant phenotypes result from a missense mutation in OsCESA4 (G858R), a highly conserved residue at the end of the fifth transmembrane domain. The aberrant secondary cell wall of the mutant plants is attributed to significantly reduced cellulose content, abnormal secondary wall structure of sclerenchyma cells, and overall altered wall composition, as detected by chemical analyses and immunochemical staining. Importantly, we have found that this point mutation decreases the abundance of OsCESA4 in the plasma membrane, probably due to a defect in the process of CESA complex secretion. The data from our biochemical, genetic, and pharmacological analyses indicate that this residue is critical for maintaining the normal level of CESA proteins in the plasma membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Biomechanical Phenomena
  • Cell Membrane / metabolism*
  • Cell Wall / genetics
  • Cell Wall / metabolism*
  • Gene Expression Regulation, Plant / genetics
  • Gene Expression Regulation, Plant / physiology
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Membrane Proteins / physiology*
  • Microscopy, Confocal
  • Microscopy, Electron, Transmission
  • Molecular Sequence Data
  • Mutation, Missense
  • Oryza / genetics
  • Oryza / growth & development
  • Oryza / metabolism*
  • Oryza / ultrastructure
  • Phylogeny
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / growth & development
  • Plants, Genetically Modified / metabolism*
  • Plants, Genetically Modified / ultrastructure
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid

Substances

  • Membrane Proteins
  • Plant Proteins