Stem cell maintenance is essential for plant growth and development. In the root apical meristem of Arabidopsis thaliana, the quiescent center (QC) is required to maintain the stemness of surrounding stem cells, such as columella stem cells (CSCs) that reside in a single layer underneath the QC. The CSC undergoes asymmetric division; the QC-adjacent daughter cell remains as a CSC, while the QC-distal daughter cell loses mitotic activity and differentiates into a columella cell (CC). The asymmetric division of CSC provides a new CC layer, while maintaining a single CSC layer. Thus, determining the cell fate of CSCs and their daughters according to their relative position to the QC is critical for continuous root growth. We previously reported that decreased Cyclin-Dependent Kinase (CDK) activities promote CSC differentiation, suggesting the involvement of CDKs in maintaining stemness (Umeda et al., 2000). However, how CDK activity controls stem cell maintenance has remained elusive. In this study, we examined the role of CDK inhibitors (CKIs), which negatively control CDK activity, in CSC maintenance and differentiation. Our data showed that one CKI is involved in CSC differentiation and its accumulation, which is mainly regulated at the transcriptional level, specifying cell fates of stem cell daughters. We shall present our progress in searching for the upstream transcriptional factors that regulate the accumulation pattern of this CKI. Understanding the role of the transcription factors will bring valuable insight into the QC-derived positional information controlling the stemness in the root meristem.