CNRS, INRA, ENS Lyon, UCBL, Université de Lyon, Laboratoire de Reproduction et Développement des Plantes, 46 Allée d'Italie, 69364 Lyon Cedex 07, France.
Development. 2012 Sep;139(18):3402-12. doi: 10.1242/dev.078212.
When a plant germinates in the soil, elongation of stem-like organs is enhanced whereas leaf and root growth is inhibited. How these differential growth responses are orchestrated by light and integrated at the organismal level to shape the plant remains to be elucidated. Here, we show that light signals through the master photomorphogenesis repressor COP1 to coordinate root and shoot growth in Arabidopsis. In the shoot, COP1 regulates shoot-to-root auxin transport by controlling the transcription of the auxin efflux carrier gene PIN-FORMED1 (PIN1), thus appropriately tuning shoot-derived auxin levels in the root. This in turn directly influences root elongation and adapts auxin transport and cell proliferation in the root apical meristem by modulating PIN1 and PIN2 intracellular distribution in the root in a COP1-dependent fashion, thus permitting a rapid and precise tuning of root growth to the light environment. Our data identify auxin as a long-distance signal in developmental adaptation to light and illustrate how spatially separated control mechanisms can converge on the same signaling system to coordinate development at the whole plant level.
当植物在土壤中发芽时，茎状器官的伸长增强，而叶片和根的生长受到抑制。光如何协调这些不同的生长反应，并在生物体水平上整合，从而塑造植物，这仍然需要阐明。在这里，我们表明，光信号通过主光形态建成抑制因子 COP1 来协调拟南芥的根和茎的生长。在地上部分，COP1 通过控制生长素外排载体基因 PIN-FORMED1 (PIN1) 的转录来调节地上部分到根的生长素运输，从而在根中适当调整来源于地上部分的生长素水平。这反过来又直接影响根的伸长，并通过调节 COP1 依赖的 PIN1 和 PIN2 在内质网中的分布来适应根顶端分生组织中的生长素运输和细胞增殖，从而允许快速而精确地根据光照环境来调整根的生长。我们的数据确定了生长素是对光的发育适应的长距离信号，并说明了空间分离的控制机制如何汇聚到同一个信号系统，从而协调整个植物水平的发育。
