Research by Prof. Chun-Ming Liu's group revealed that peptide hormones are critical for plant development. The investigators found that the C-terminal domain of the CLE family proteins (31 members in Arabidopsis genome) was processed to small peptides, used by plants for inter-cellular signal transduction through LRR-receptor kinases. CLV3, one of the CLE members, functions in shoot apical meristem to restrict the number of stem cells and promote cell differentiation (Current Opinion in Plant Biology, 2007).

Figure. The CLV-WUS stem cell regulation loop and the expression of related genes.