Quiescent center formation in maize roots is associated with an auxin-regulated oxidizing environment
Quiescent center formation in maize roots is associated with an auxin-regulated oxidizing environment
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DOI：
10.1242/dev.00359
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发表时间：
2003-04-01
期刊：
影响因子：
4.6
通讯作者：
Feldman, LJ
中科院分区：
文献类型：
--
作者：
Jiang, K;Meng, YL;Feldman, LJ
所有被子植物根的分生组织内都有一群缓慢分裂的细胞，称为静止中心（QC）。在玉米根中，QC可以构成800-1200个以上的细胞，其中大多数在细胞周期的G（1）期花费较长的时间（180-200小时）。QC如何形成和维护尚不清楚。在这里，我们报告的QC细胞的特点是其高度氧化状态。谷氨酸和抗坏血酸主要以氧化形式存在于QC中。这与根分生组织中相邻的快速分裂细胞中这些氧化还原中间体的状态形成鲜明对比，其中这两个物种的还原形式受到青睐。使用氧化还原敏感的荧光染料，我们能够可视化的QC中的整体氧化环境，我们还与相邻的，快速分裂的细胞在根分生组织中进行了比较。改变生长素的分布和根尖中生长素最大值的位置激活QC，细胞离开G（1）并进入有丝分裂。QC中相对更快的细胞分裂的开始之前是QC的整体氧化还原状态的变化，其变得更少氧化。我们讨论了生长素最大值的位置如何影响QC的氧化还原状态，从而调节细胞周期。
Embedded within the meristem of all Angiosperm roots is a population of slowly dividing cells designated the quiescent center (QC). In maize roots the QC can constitute upwards of 800-1200 cells, most of which spend an extended period of time (180-200 hours) in the G(1) phase of the cell cycle. How the QC forms and is maintained is not known. Here we report that cells of the QC are characterized by their highly oxidized status. Glutathione and ascorbic acid occur predominately in the oxidized forms in the QC. This is contrasted with the status of these redox intermediates in adjacent, rapidly dividing cells in the root meristem, in which the reduced forms of these two species are favored. Using a redox sensitive fluorescent dye we were able to visualize an overall oxidizing environment in the QC, and we also made comparisons with the adjacent, rapidly dividing cells in the root meristem. Altering the distribution of auxin and the location of the auxin maximum in the root tip activates the QC, and cells leave G(1) and enter mitosis. Commencement of relatively more rapid cell division in the QC is preceded by changes in the overall redox status of the QC, which becomes less oxidizing. We discuss how the position of the auxin maximum may influence the redox status of the QC and thereby modulate the cell cycle.