Abstract:

Plant stem cells are characterized with two main features of the self-renewal and their potential to differentiate into multiple cell types. Plant stem cells are believed to have important roles in controlling the balance between organ formation and meristem maintenance. We review the studies on the organization models in the three kinds of meristems (shoot apical, root apical and vascular cambium) and the WUSCHEL/CLAVATA(WUS/CLV) feedback regulatory mechanisms in plant stem cell niche. In summary, the three kinds of meristems not only have similar potential for maintaining initials over long periods in the plant stem cell niche, but also have a similar cell niche (or zone) to regulate the adjacent stem cell division or differentiation by their structural comparison. A similar feedback regulatory mechanism exists in shoot apical meristem (SAM) and in root apical meristem (RAM), respectively identified as WUS/CLV and WOX 5 /CLE 40 , and they all have a function in maintaining a balance between stem cell division and other tissues formation. There are limited reports on the WUS/CLV feedback regulatory mechanism in vascular cambium (VCAM), especial on woody plants. However, we propose that there would be a similar mechanism in VCAM stem cell niche.

Key words: plant stem cell, SAM, RAM, VCAM, WUS, CLV, feedback regulatory mechanism