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, China.
College of Life Science, Nanjing Agricultural University, Nanjing, 210095, China.
Plant Cell Environ. 2019 Dec;42(12):3182-3196. doi: 10.1111/pce.13635. Epub 2019 Aug 18.
A biological clock activated by oscillating signals, known as root clock, has been linked to lateral root (LR) formation and is essential for regular LR spacing along the primary root. However, it remains unclear how this internal mechanism is influenced by environmental factors known to affect the LR pattern. Here, we report that excessive cadmium (Cd) inhibits LR formation by disrupting the lateral root cap (LRC)-programmed cell death (PCD)-regulated root clock. Cd restricts the frequency of the oscillating signal rather than its amplitude. This could be attributed to the inhibition on meristematic activity by Cd, which resulted in decreased LRC cell number and LRC-PCD frequency. Genetic evidence further showed that LRC cell number is positively correlated with root resistance to Cd. Our study reveals root cap dynamics as a novel mechanism mediating root responses to Cd, providing insight into the signalling pathways of the root clock responding to environmental cues.
一个由振荡信号激活的生物钟，被称为根钟，与侧根（LR）的形成有关，并且对于沿着主根的规则的 LR 间距是必需的。然而，目前尚不清楚这个内部机制如何受到已知影响 LR 模式的环境因素的影响。在这里，我们报告说，过量的镉（Cd）通过破坏侧根帽（LRC）-编程细胞死亡（PCD）调控的根钟来抑制 LR 的形成。Cd 限制了振荡信号的频率，而不是幅度。这可能归因于 Cd 对分生组织活性的抑制，导致 LRC 细胞数量和 LRC-PCD 频率降低。遗传证据进一步表明，LRC 细胞数量与根对 Cd 的抗性呈正相关。我们的研究揭示了根帽动力学作为一种新的机制，调节根对 Cd 的反应，为根钟对环境信号做出反应的信号通路提供了深入的了解。
