Two-Step Regulation of a Meristematic Cell Population Acting in Shoot Branching in Arabidopsis.
Two-Step Regulation of a Meristematic Cell Population Acting in Shoot Branching in Arabidopsis.
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拟南芥分生组织细胞群在芽分枝中的两步调控
DOI：
10.1371/journal.pgen.1006168
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发表时间：
2016-07
期刊：
影响因子：
4.5
通讯作者：
Jiao Y
中科院分区：
文献类型：
--
作者：
Shi B;Zhang C;Tian C;Wang J;Wang Q;Xu T;Xu Y;Ohno C;Sablowski R;Heisler MG;Theres K;Wang Y;Jiao Y
芽分枝需要建立新的分生组织窝藏干细胞，这种现象提出了问题的精确调控分生组织的命运。在种子植物中，这些新的分生组织起源于叶腋，使侧枝能够分枝。使用叶腋细胞的活细胞成像，我们表明，腋生分生组织的启动需要一个分生组织细胞群体不断表达分生组织标记SHOOT MERISTEMLESS（STM）。STM表达的维持依赖于叶腋生长素的最小值。STM的异位表达不足以激活失去叶腋STM表达细胞的植物的腋芽形成。这表明一些细胞经历了不可逆的发育命运。在更成熟的叶片中，REVOLUTA（REV）直接上调STM在叶腋分生组织细胞中的表达，但不上调在分化细胞中的表达，以建立腋生分生组织。REV与STM区域的细胞类型特异性结合与表观遗传修饰相关。我们的数据有利于腋生分生组织起始的阈值模型，其中低水平的STM维持分生能力，高水平的STM导致分生组织起始。
Shoot branching requires the establishment of new meristems harboring stem cells; this phenomenon raises questions about the precise regulation of meristematic fate. In seed plants, these new meristems initiate in leaf axils to enable lateral shoot branching. Using live-cell imaging of leaf axil cells, we show that the initiation of axillary meristems requires a meristematic cell population continuously expressing the meristem marker SHOOT MERISTEMLESS (STM). The maintenance of STM expression depends on the leaf axil auxin minimum. Ectopic expression of STM is insufficient to activate axillary buds formation from plants that have lost leaf axil STM expressing cells. This suggests that some cells undergo irreversible commitment to a developmental fate. In more mature leaves, REVOLUTA (REV) directly up-regulates STM expression in leaf axil meristematic cells, but not in differentiated cells, to establish axillary meristems. Cell type-specific binding of REV to the STM region correlates with epigenetic modifications. Our data favor a threshold model for axillary meristem initiation, in which low levels of STM maintain meristematic competence and high levels of STM lead to meristem initiation.