Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
Dev Biol. 2009 Dec 1;336(1):1-9. doi: 10.1016/j.ydbio.2009.09.031. Epub 2009 Sep 25.
At the shoot apex of plants is a small region known as the shoot apical meristem (SAM) that maintains a population of undifferentiated (stem) cells whilst providing cells for developing lateral organs and the stem. All aerial structures of the plant develop from the SAM post-embryogenesis, enabling plants to grow in a characteristic modular fashion with great phenotypic and developmental plasticity throughout their lifetime. The maintenance of the stem cell population is intimately balanced with cell recruitment into differentiating tissues through intercellular communication involving a complex signalling network. Recent studies have shown that diverse regulators function in SAM maintenance, many of which converge on the WUSCHEL (WUS) gene. In this review the diverse regulatory modules that function in SAM maintenance are discussed: transcriptional and epigenetic control, hormonal regulation, and the balance with organogenesis. The central role of WUS as an integrator of multiple signals is highlighted; in addition, accessory feedback loops emerge as a feature enabling dynamic regulation of the stem cell niche.
在植物的芽尖有一个小区域，称为芽尖分生组织（SAM），它维持着一群未分化的（茎）细胞，同时为发育中的侧生器官和茎提供细胞。植物的所有气生结构都是从 SAM 后胚胎发生发育而来的，这使得植物能够以特征性的模块化方式生长，在其整个生命周期中具有很强的表型和发育可塑性。干细胞群体的维持与通过细胞间通讯将细胞募集到分化组织中密切平衡，涉及复杂的信号网络。最近的研究表明，多种调节剂在 SAM 维持中发挥作用，其中许多调节剂都集中在 WUSCHEL（WUS）基因上。在这篇综述中，讨论了在 SAM 维持中起作用的多种调节模块：转录和表观遗传控制、激素调节以及与器官发生的平衡。WUS 作为多种信号整合者的核心作用被强调；此外，辅助反馈回路的出现是动态调节干细胞生态位的一个特征。
