Cell Differentiation in Shoot Meristem: A Molecular Perspective

Abstract

The basic body plan of higher plants is laid down during embryogenesis, however, the entire adult plant develops post-embryonically through the activity of two meristems (shoot and root apical meristems) established originally at the opposite ends of the embryo. This article focuses on the shoot apical meristem (SAM), which is primarily responsible for the formation of leaves and stems in the vegetative phase and converts into reproductive meristem at a specific stage of development. The SAM comprises a central zone harboring a reservoir of pluripotent stem cells and a peripheral zone, which gives rise to primordia for organs such as leaves and flowers. Studies in the past decade have unravelled some of the molecular pathways that determine stem cell fate in the central portion of the SAM as well as regulate organ formation from peripheral zone of SAM. These studies are providing insight into the information flow between various zones and cell layers of the SAM that helps in stabilizing the size of the stem cell population, so vital for cellular proliferation and regulation of plant growth and development.