Fig. 3

The CLE–BAM–CIK signaling pathway regulates protophloem differentiation. Perception of CLE 25/26/45 ligands by the extracellular domain of BAM1/3 receptors located on the plasma membrane triggers the interaction between BAM1/3 and CIKs. The BAM–CIK receptor complex then undergoes phosphorylation. The phosphorylated receptor complex subsequently leads to phosphorylation of PBL34/35/36, mediating downstream signaling events to regulate protophloem differentiation and maintain root meristem homeostasis