Characterization of the maize xylem sap proteome

J Proteome Res. 2006 Apr;5(4):963-72. doi: 10.1021/pr050471q.


The xylem in plants has mainly been described as a conduit for water and minerals, but emerging evidence also indicates that the xylem contains protein. To study the proteins in xylem sap, we characterized the identity and composition of the maize xylem sap proteome. The composition of the xylem sap proteome in maize revealed proteins related to different phases of xylem differentiation including cell wall metabolism, secondary cell wall synthesis, and programmed cell death. Many proteins were found to be present as multiple isoforms and some of these isoforms are glycosylated. Proteins involved in defense mechanisms were also present in xylem sap and the sap proteins were shown to have antifungal activity in bioassays.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Antifungal Agents / chemistry
  • Antifungal Agents / pharmacology
  • Electrophoresis, Gel, Two-Dimensional
  • Glycosylation
  • Histocytochemistry
  • Nanotechnology
  • Neurospora crassa / drug effects
  • Peptide Mapping
  • Plant Extracts / chemistry
  • Plant Proteins / analysis
  • Plant Proteins / isolation & purification
  • Plant Structures / chemistry*
  • Plant Structures / physiology*
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Proteome / analysis*
  • Sequence Analysis, Protein
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Trypsin / pharmacology
  • Zea mays / anatomy & histology*
  • Zea mays / chemistry*
  • Zea mays / growth & development
  • Zea mays / physiology


  • Antifungal Agents
  • Plant Extracts
  • Plant Proteins
  • Protein Isoforms
  • Proteome
  • Trypsin