State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, B-9052 Ghent, Belgium.
Development. 2020 Feb 3;147(3):dev181446. doi: 10.1242/dev.181446.
Plants explore the soil by continuously expanding their root system, a process that depends on the production of lateral roots (LRs). Sites where LRs can be produced are specified in the primary root axis through a pre-patterning mechanism, determined by a biological clock that is coordinated by temporal signals and positional cues. This 'root clock' generates an oscillatory signal that is translated into a developmental cue to specify a set of founder cells for LR formation. In this Review, we summarize recent findings that shed light on the mechanisms underlying the oscillatory signal and discuss how a periodic signal contributes to the conversion of founder cells into LR primordia. We also provide an overview of the phases of the root clock that may be influenced by endogenous factors, such as the plant hormone auxin, and by exogenous environmental cues. Finally, we discuss additional aspects of the root-branching process that act independently of the root clock.
植物通过不断扩展根系来探索土壤，这一过程依赖于侧根 (LR) 的产生。通过一个预先形成的机制，可以在主根轴上指定产生侧根的位置，该机制由生物钟协调，生物钟受时间信号和位置线索的影响。这个“根时钟”产生一个振荡信号，将其转化为发育线索，指定一组用于形成侧根的起始细胞。在这篇综述中，我们总结了最近的发现，这些发现揭示了振荡信号背后的机制，并讨论了周期性信号如何有助于将起始细胞转化为侧根原基。我们还概述了根时钟的各个阶段，这些阶段可能受到内源性因素（如植物激素生长素）和外源性环境线索的影响。最后，我们讨论了与根时钟独立作用的侧根分支过程的其他方面。
