Ricerc@Sapienza

In the Arabidopsis thaliana root, stem cells divide in the apical stem cell niche of the meristem and originate daughter cells that divide until they reach a distal boundary denominated transition zone where they start differentiating. At the end of root meristem development a balance between cell division and cell differentiation is reached to maintain indeterminate root grow. This balance is regulated by the antagonistic interaction of two hormones: auxin that promotes cell division, and cytokinin that promotes cell differentiation.
Cytokinin controls cell differentiation via the ARR1 transcription factor, specifically expressed at the transition zone. Aim of this project is to understand the role of a newly identified transcription factor, ARR10 that, unlike ARR1, is expressed in the meristem where cells are still dividing. These observations, together with the analysis of arr10 knock out mutants, suggest the interesting hypothesis that ARR10 contributes to balance cell division with cell differentiation repressing, in the meristem, cell division. As such cytokinin, by activating at the same time ARR1 at the transition zone and ARR10 in the meristem, establish the balance of cell division with cell differentiation, thus ensuring indeterminate root grow.