The protein expression landscape of the Arabidopsis root


  • J.J. Petricka
  • M.A. Schauer
  • M. Megraw
  • N.W. Breakfield
  • J.W. Thompson
  • S. Georgiev
  • E.J. Soderblom
  • U. Ohler
  • M.A. Moseley
  • U. Grossniklaus
  • P.N. Benfey


  • Proceedings of the National Academy of Sciences of the United States of America


  • Proc Natl Acad Sci U S A 109 (18): 6811-6818


  • Because proteins are the major functional components of cells, knowledge of their cellular localization is crucial to gaining an understanding of the biology of multicellular organisms. We have generated a protein expression map of the Arabidopsis root providing the identity and cell type-specific localization of nearly 2,000 proteins. Grouping proteins into functional categories revealed unique cellular functions and identified cell type-specific biomarkers. Cellular colocalization provided support for numerous protein-protein interactions. With a binary comparison, we found that RNA and protein expression profiles are weakly correlated. We then performed peak integration at cell type-specific resolution and found an improved correlation with transcriptome data using continuous values. We performed GeLC-MS/MS (in-gel tryptic digestion followed by liquid chromatography-tandem mass spectrometry) proteomic experiments on mutants with ectopic and no root hairs, providing complementary proteomic data. Finally, among our root hair-specific proteins we identified two unique regulators of root hair development.