Pericycle cell proliferation and lateral root initiation in arabidopsis
Pericycle cell proliferation and lateral root initiation in arabidopsis
复制标题
DOI：
10.1104/pp.124.4.1648
复制
发表时间：
2000-12-01
期刊：
影响因子：
7.4
通讯作者：
Rost, TL
中科院分区：
文献类型：
--
作者：
Dubrovsky, JG;Doerner, PW;Rost, TL
与拟南芥根尖分生组织产生的其他细胞相反，邻近维管柱原木质部极的中柱鞘细胞在通过伸长和分化区期间继续循环而不中断。然而，只有一些分裂的中柱鞘细胞进行不对称的形成性分裂，从而产生侧根原基（LRP）。通过直接观察和绘制有丝分裂图、细胞长度测量以及中柱鞘细胞中细胞周期蛋白-GUS 融合蛋白的组织化学分析证明了这一点。根尖分生组织中中柱鞘细胞周期的估计持续时间与细胞从分生组织移位到 LRP 形成开始之间的间隔相似。受发育控制的 LRP 起始发生较早，距根尖 3 至 8 毫米。因此，侧根形成中的第一个生长控制点是由细胞通过伸长区和幼分化区以随机模式启动原基，直至侧根开始从主根出现的地方。因此，第一生长控制点不限于狭窄的发育窗口。我们认为晚期 LRP 启动在发育上与根尖分生组织无关，并且由可通过环境线索激活的第二个生长控制点操作。在没有干预有丝分裂静止的情况下中柱鞘细胞分裂和侧根原基形成的观察表明，根和芽中侧器官的形成可能并不像以前认为的那样根本不同。
In contrast with other cells generated by the root apical meristem in Arabidopsis, pericycle cells adjacent to the protoxylem poles of the vascular cylinder continue to cycle without interruption during passage through the elongation and differentiation zones. However, only some of the dividing pericycle cells are committed to the asymmetric, formative divisions that give rise to lateral root primordia (LRPs). This was demonstrated by direct observation and mapping of mitotic figures, cell-length measurements, and the histochemical analysis of a cyclin-GUS fusion protein in pericycle cells. The estimated duration of a pericycle cell cycle in the root apical meristem was similar to the interval between cell displacement from the meristem and the initiation of LRP formation. Developmentally controlled LRP initiation occurs early, 3 to 8 mm from the root tip. Thus the first growth control point in lateral root formation is defined by the initiation of primordia in stochastic patterns by cells passing through the elongation and young differentiation zones, up to where lateral roots begin to emerge from the primary root. Therefore, the first growth control point is not restricted to a narrow developmental window. We propose that late LRP initiation is developmentally unrelated to the root apical meristem and is operated by a second growth control point that can be activated by environmental cues. The observation that pericycle cells divide and lateral root primordia form without intervening mitotic quiescence suggests that lateral organ formation in roots and shoots might not be as fundamentally different as previously thought.