Cytokinin promotes growth cessation in the Arabidopsis root

第一作者：Shanda Liu

第一单位：马克斯·普朗克植物育种研究所

通讯作者：Miltos Tsiantis

 Abstarct 

背景回顾：The Arabidopsis root offers good opportunities to investigate how regulated cellular growth shapes different tissues and organs, a key question in developmental biology. Along the root’s longitudinal axis, cells sequentially occupy different developmental states. Proliferative meristematic cells give rise to differentiating cells, which rapidly elongate in the elongation zone, then mature and stop growing in the differentiation zone. The phytohormone cytokinin contributes to this zonation by positioning the boundary between the meristem and the elongation zone, called the transition zone. 

拟南芥的根为研究受调控的细胞生长如何塑造不同的组织和器官提供了一个合适的平台，该问题是发育生物学领域的一个关键问题。沿着根的纵轴，细胞依次处于不同的发育状态。具增殖活性的分生组织细胞会产生分化的细胞，接着这些细胞会在伸长区迅速伸长，然后在分化区成熟并停止生长。植物激素细胞分裂素通过定位分生组织和伸长区之间的边界（也称为过渡区）来促进根中的分区。

提出问题：However, the cellular growth profile underlying root zonation is not well understood, and the cellular mechanisms that mediate growth cessation remain unclear. 

然而，目前对与根分区背后的细胞生长过程仍所知甚少，并且对于介导生长停止的细胞机制尚不清楚。

主要研究： By using time-lapse imaging, genetics, and computational analysis, we analyze the effect of cytokinin on root zonation and cellular growth. 

本文中，作者通过延时成像、遗传学和计算分析研究了细胞分裂素对根分区和细胞生长的影响。

结果：We found that cytokinin promotes growth cessation in the distal (shootward) elongation zone in conjunction with accelerating the transition from elongation to differentiation. We estimated cell-wall stiffness by using osmotic treatment experiments and found that cytokinin-mediated growth cessation is associated with cell-wall stiffening and requires the action of an auxin influx carrier, AUX1. 

作者发现细胞分裂素促进远端（朝向地上组织一侧）伸长区的生长停止，同时加速细胞从伸长到分化的转变。作者通过渗透处理实验估计细胞壁硬度，发现细胞分裂素介导的生长停止与细胞壁硬度相关，并且需要生长素内流载体蛋白AUX1的作用。

结论：Our measurement of growth and cell-wall mechanical properties at a cellular resolution reveal mechanisms via which cytokinin influences cell behavior to shape tissue patterns.

本文对于细胞水平上的生长和细胞壁机械性能测量，揭示了细胞分裂素影响细胞行为的分子机制，从而塑造组织模式。

** Miltos Tsiantis **

doi: https://doi.org/10.1016/j.cub.2022.03.019

Journal: Current Biology

Published date: March 29, 2022