The cell morphogenesis gene SPIRRIG in Arabidopsis encodes a WD/BEACH domain protein

Plant J. 2009 Aug;59(4):612-21. doi: 10.1111/j.1365-313X.2009.03900.x. Epub 2009 Apr 25.


WD40/BEACH domain proteins have been implicated in membrane trafficking and membrane composition events in Dictyostelium and Drosophila. In this paper, we show that the Arabidopsis SPIRRIG (SPI) gene encodes a WD40/BEACH domain protein. The cellular analysis revealed fragmented vacuoles in root hairs similar to those found in the corresponding Dictyostelium mutants, suggesting a related cellular function. The phenotypic analysis revealed that spi mutants share all phenotypic aspects of mutants in the actin polymerization-regulating ARP2/3 pathway, including distorted trichomes, less lobing of epidermal pavement cells, disconnected epidermal cells on various organs, and shorter root hairs. This complete phenotypic overlap suggests that this WD40/BEACH domain protein and the actin-regulating ARP2/3 pathway are involved in similar growth processes.

MeSH terms

  • Actin-Related Protein 2-3 Complex / metabolism
  • Arabidopsis / cytology
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Chromosome Mapping
  • Cloning, Molecular
  • DNA, Plant / genetics
  • Gene Expression Regulation, Plant
  • Genes, Plant
  • Mutation
  • Phylogeny
  • Plant Roots / cytology
  • Plant Roots / genetics
  • Vacuoles / ultrastructure


  • Actin-Related Protein 2-3 Complex
  • Arabidopsis Proteins
  • DNA, Plant