Oriented cell divisions are crucial for determining the overall morphology and size of plants, but what controls the onset and duration of this process remains largely unknown. Here, we identified a small molecule that activates root apical meristem (RAM) expression of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE13 (SPL13) a known player in the shoot’s juvenile-to-adult transition. This expression leads to oriented cell divisions in the RAM through SHORT ROOT (SHR) and cell cycle regulators. We further show that the RAM has distinct juvenile and adult phases typed by morphological and molecular characteristics and that SPL factors are crucially required for this transition in Arabidopsis and rice ( Oryza sativa ). In summary, we provide molecular insights into the age-dependent morphological changes occurring in the RAM during phase change.

中文翻译：

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SPL13 通过触发定向细胞分裂来控制根尖分生组织的相位变化


定向细胞分裂对于确定植物的整体形态和大小至关重要，但控制这一过程开始和持续时间的因素在很大程度上仍然未知。在这里，我们鉴定了一个小分子，它激活鳞状启动子结合蛋白 13 （SPL13） 的根尖分生组织 （RAM） 表达，SPL13 是芽从幼年到成虫过渡的已知参与者。这种表达导致 RAM 中通过 SHORT ROOT （SHR） 和细胞周期调节因子定向细胞分裂。我们进一步表明，RAM 具有由形态和分子特征分型的不同幼年和成虫阶段，并且 SPL 因子对于拟南芥和水稻 （Oryza sativa） 的这种转变至关重要。总之，我们提供了关于相变过程中 RAM 中发生的年龄依赖性形态变化的分子见解。