Submitted to: Annual Reviews of Plant Biology
Publication Type: Review Article
Publication Acceptance Date: December 10, 2001
Publication Date: April 1, 2002
Interpretive Summary: This article summarizes the current state of knowledge of how plants are able to produce organs throughout their lives, by maintaining a continuously growing tip called a shoot apical meristem. I discuss the structure of the Arabidopsis shoot meristem, the genes that maintain the growth of the meristem, the protein complex that is used by meristem cells to communicate with one another, and ways in which flower-producing meristems differ from stem-producing meristems.
Technical Abstract: The shoot apical meristem of higher plants functions as a site of continuous organogenesis, within which a small pool of pluripotent stem cells replenishes the cells incorporated into lateral organs. This article summarizes recent results demonstrating that the fate of stem cells in Arabidopsis shoot and floral meristems is controlled by overlapping spatial and temporal signaling systems. Stem cell maintenance is an active process requiring constant communication between neighboring groups of SAM cells. Information flows via a ligand-receptor signal transduction pathway, resulting in the formation of a spatial feedback loop that stabilizes the size of the stem cell population. Termination of stem cell activity during flower development is achieved by a temporal feedback loop involving both stem cell maintenance genes and flower patterning genes. These investigations are providing exciting insights into the components and activities of the stem cell regulatory pathway, and into the interaction of this pathway with molecular mechanisms that control floral patterning.