The Stem Cell Niche in Leaf Axils Is Established by Auxin and Cytokinin in Arabidopsis[W]
The Stem Cell Niche in Leaf Axils Is Established by Auxin and Cytokinin in Arabidopsis[W]
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DOI：
10.1105/tpc.114.123083
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发表时间：
2014-05
期刊：
影响因子：
11.6
通讯作者：
Ying Wang;Jin Wang;Bihai Shi;Ting Yu;Jiyan Qi;E. Meyerowitz;Yuling Jiao
中科院分区：
文献类型：
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作者：
Ying Wang;Jin Wang;Bihai Shi;Ting Yu;Jiyan Qi;E. Meyerowitz;Yuling Jiao
分支分生组织允许植物形成新的生长和发育周期的分支系统。本研究表明，腋生分生组织的形成受两种经典植物激素的调控，其中生长素抑制腋生分生组织的形成，细胞分裂素促进腋生分生组织的形成。植物与大多数动物的不同之处在于它们启动新的生长和发育周期的能力，这依赖于分支分生组织的建立和活动，这些分支分生组织含有新的干细胞生态位。在种子植物中，这是通过腋生分生组织实现的，腋生分生组织建立在每个叶基的叶腋上，并发育成侧枝。在这里，我们描述了拟南芥腋窝分生组织起始的初始过程。通过报告基因表达分析，我们发现腋生分生组织是从生长素水平较低的叶腋细胞经过典型阶段形成的。与此一致的是，叶腋中生长素的异位过量产生有效地抑制了腋窝分生组织的形成。此外，我们的研究结果表明，生长素外排是叶腋生长素最小值和腋生分生组织形成所必需的。在生长素水平降低后，随后的细胞分裂素信号脉冲在腋窝分生组织开始之前被观察到。遗传分析表明细胞分裂素感知和信号传导都是腋窝分生组织形成所必需的。最后，我们发现叶腋细胞分裂素的过量产生部分挽救了腋窝分生组织启动缺陷突变体。这些结果为理解腋窝分生组织的形成提供了一个机制框架。
Branch meristems allow plants to form ramifying systems with new cycles of growth and development. This work shows that the establishment of axillary meristems is regulated by two classical phytohormones, with auxin suppressing and cytokinins promoting axillary meristem initiation. Plants differ from most animals in their ability to initiate new cycles of growth and development, which relies on the establishment and activity of branch meristems harboring new stem cell niches. In seed plants, this is achieved by axillary meristems, which are established in the axil of each leaf base and develop into lateral branches. Here, we describe the initial processes of Arabidopsis thaliana axillary meristem initiation. Using reporter gene expression analysis, we find that axillary meristems initiate from leaf axil cells with low auxin through stereotypical stages. Consistent with this, ectopic overproduction of auxin in the leaf axil efficiently inhibits axillary meristem initiation. Furthermore, our results demonstrate that auxin efflux is required for the leaf axil auxin minimum and axillary meristem initiation. After lowering of auxin levels, a subsequent cytokinin signaling pulse is observed prior to axillary meristem initiation. Genetic analysis suggests that cytokinin perception and signaling are both required for axillary meristem initiation. Finally, we show that cytokinin overproduction in the leaf axil partially rescue axillary meristem initiation-deficient mutants. These results define a mechanistic framework for understanding axillary meristem initiation.