During organogenesis, coherent organ growth arises from spatiotemporally coordinated decisions of individual cells. In the root of Arabidopsis thaliana, this coordination results in the establishment of a division and a differentiation zone. Cells continuously move through these zones; thus, a major question is how the boundary between these domains, the transition zone, is formed and maintained. By combining molecular genetics with computational modeling, we reveal how an auxin/PLETHORA/ARR-B network controls these dynamic patterning processes. We show that after germination, cell division causes a drop in distal PLT2 levels that enables transition zone formation and ARR12 activation. The resulting PLT2-ARR12 antagonism controls expansion of the division zone (the meristem). The successive ARR1 activation antagonizes PLT2 through inducing the cell-cycle repressor KRP2, thus setting final meristem size. Our work indicates a key role for the interplay between cell division dynamics and regulatory networks in root zonation and transition zone patterning.

中文翻译：

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自组织的PLT / Auxin / ARR-B网络控制拟南芥中根区的动态发育。

在器官发生期间，相干器官的生长是由单个细胞的时空协调决定引起的。在拟南芥的根中，这种协调导致建立分裂和分化区。细胞不断穿过这些区域。因此，一个主要的问题是这些域之间的边界（过渡区）是如何形成和维持的。通过将分子遗传学与计算模型相结合，我们揭示了生长素/ PLETHORA / ARR-B网络如何控制这些动态构图过程。我们表明发芽后，细胞分裂导致远端PLT2水平下降，使过渡区形成和ARR12激活。产生的PLT2-ARR12拮抗作用控制分裂区（分生组织）的扩展。连续的ARR1激活通过诱导细胞周期阻遏物KRP2拮抗PLT2，从而设定最终的分生组织大小。我们的工作表明了细胞分裂动力学和调控网络在根区和过渡区模式中相互作用的关键作用。