Topic 18.11 Maintenance of Meristem Activity Is Crucial for Seedling Establishment

Topic 18.11 Maintenance of Meristem Activity Is Crucial for Seedling Establishment

The CLAVATA pathway is important for shoot meristem identity and maintenance. Although there is no evidence for the functioning of this signal transduction pathway in roots, the CLAVATA small signaling peptides CLE19 and CLE40 are expressed in roots. When CLE19 is overexpressed, the root meristem becomes determinate. A CLE19 suppressor screen identified the zinc carboxypeptidase SOL1, which processes CLE19. The zinc aminopeptidase APM1 has been identified as preventing premature primary root determinacy. A gradient of CLE and CLE-like peptides exists within the root, with those in the meristematic zone promoting meristem maintenance and repressing vascular maturation, while the CLE peptides in the maturation zone promote vascular development.