Abstract
In higher plants, stem cells are maintained in the shoot apical meristem (SAM) and the root meristem (RM), thus allowing post-embryonic organogenesis. In SAM,WUSCHEL is shown to contribute to stem cell maintenance non-cell-autonomously. In RM, the quiescent center (QC), which is a small group of mitotically less active cells, has been postulated to prevent differentiation of surrounding stem cells, but little is known about the molecular mechanisms underlying this non-cell-autonomous cellular signaling.
Recently, WUSCHEL-related Homeobox 5 (WOX5) was reported to be expressed specifically in the QC. In this study, we investigated the role of WOX5 in stem cell maintenance. Analyses of loss-of-function wox5 mutants and the transgenic plants that ectopically express WOX5 suggested that WOX5 maintains undifferentiated status of the stem cells located distal to QC, but that those located basal to QC are maintained by pathways that act either separately from or redundantly with WOX5.
