Brassicaceae-specific phytocytokine (plant endogenous peptide released into the apoplast) perceived by MIK2 in a BAK1/SERK3 and SERK4 coreceptors-dependent manner, that modulates various physiological and antimicrobial processes including growth prevention and reactive oxygen species (ROS) response regulation (PubMed:33514716, PubMed:34535661). Inhibits root growth and regulates root meristems (PubMed:34535661). Promotes ROS production and MAPK (e.g. MPK3, MPK4 and MPK6) activation in a MIK2-dependent manner, thus leading to the up-regulation of immune-related marker genes (e.g. WRKY30, WRKY33 and CYP81F2) (PubMed:34535661).