Extracellular signaling peptide that may regulate primary root growth rate and systemic nitrogen (N)-demand signaling. Interacts with CEP receptors (e.g. CEPR1 and CEPR2). Accumulates in xylem sap. Induced by gibberellic acid (GA) but repressed by nitrogen (N) (PubMed:24179095). Accumulates in roots in response to nitrate and ammonium chloride NH(4)Cl depletion and to osmotic stress (e.g. mannitol). Repressed in shoots by nitrogen starvation (PubMed:24179096). The mature small signaling peptide is generated by proteolytic processing of the longer precursor. Belongs to the C-terminally encoded plant signaling peptide (CEP) family.