Peptide signaling in vascular development.

In plants and animals, putative small peptide ligands have been suggested to play crucial roles in development as signal molecules of cell-cell communication. Recent studies of CLAVATA3/ENDOSPERM SURROUNDING REGION (CLE) genes and their products have revealed that distinctive dodeca-CLE peptide ligands function in various developmental processes. In particular, the finding and characterization of TDIF, a dodeca-CLE peptide suppressing tracheary element differentiation, indicates regulation of vascular organization by cell-cell communication through CLE peptides. In addition, other extracellular peptides such as phytosulfokine, proteins such as xylogen, and phytohormones all participate in the ordered formation of vascular tissues.