A glycopeptide regulating stem cell fate in Arabidopsis thaliana

The secreted peptide gene CLAVATA3 (CLV3) regulates stem cell fate in the shoot apical meristem in Arabidopsis thaliana plants, but the molecular structure of the active mature CLV3 peptide is controversial. Here, using nano-LC-MS/MS analysis of apoplastic peptides of A. thaliana plants overexpressing CLV3, we show that CLV3 is a 13-amino-acid arabinosylated glycopeptide. Post-translational arabinosylation of CLV3 is critical for its biological activity and high-affinity binding to its receptor CLV1.