Hormonal control of cell division and elongation along differentiation trajectories in roots.
Hormonal control of cell division and elongation along differentiation trajectories in roots.
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DOI：
10.1093/jxb/ert485
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发表时间：
2014-06
影响因子：
6.9
通讯作者：
Hirotomo Takatsuka;M. Umeda
中科院分区：
文献类型：
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作者：
Hirotomo Takatsuka;M. Umeda
根的持续发育由根尖细胞生产和生长的可持续系统支持。在由静止中心和周围干细胞组成的干细胞龛中，生长素和脱落酸的作用使未分化状态和低有丝分裂活性得以保持。干细胞子体在近端分生组织中分裂多次，生长素和赤霉素主要促进细胞增殖。然后细胞在赤霉素的帮助下伸长，并最终分化为伸长/分化区中的细胞群的组成部分。在模式植物拟南芥（Arabidopsis thaliana）中，过渡区位于近端分生组织和伸长/分化区之间，在有丝分裂到核内复制的转换过程中起着重要作用，从而导致DNA多倍化。最近的研究表明，细胞分裂素是基本上需要通过拮抗生长素信号和促进有丝分裂调节剂的降解，这一转变。在每个根区，不同的植物激素相互作用，协调控制细胞增殖，细胞伸长，细胞分化和内复制。这种激素网络在各种环境条件下维持根尖的精细结构。在这篇综述中，我们总结和讨论有关激素调控根生长的关键问题，并描述了植物激素是如何与细胞周期机制的控制。
The continuous development of roots is supported by a sustainable system for cell production and growth at the root tip. In the stem cell niche that consists of a quiescent centre and surrounding stem cells, an undifferentiated state and low mitotic activity are preserved by the action of auxin and abscisic acid. Stem cell daughters divide several times in the proximal meristem, where auxin and gibberellin mainly promote cell proliferation. Cells then elongate with the help of gibberellin, and become finally differentiated as a constituent of a cell file in the elongation/differentiation zone. In the model plant Arabidopsis thaliana, the transition zone is located between the proximal meristem and the elongation/differentiation zone, and plays an important role in switching from mitosis to the endoreplication that causes DNA polyploidization. Recent studies have shown that cytokinins are essentially required for this transition by antagonizing auxin signalling and promoting degradation of mitotic regulators. In each root zone, different phytohormones interact with one another and coordinately control cell proliferation, cell elongation, cell differentiation, and endoreplication. Such hormonal networks maintain the elaborate structure of the root tip under various environmental conditions. In this review, we summarize and discuss key issues related to hormonal regulation of root growth, and describe how phytohormones are associated with the control of cell cycle machinery.