Spatial specificity of auxin responses coordinates wood formation

First author: Klaus Brackmann; Affiliations: Gregor Mendel Institute (GMI), Austrian Academy of Sciences (奥地利科学院格雷戈·门德尔研究所): Vienna, Austria

Corresponding author: Thomas Greb

Spatial organization of signalling events of the phytohormone auxin is fundamental for maintaining a dynamic transition from plant stem cells to differentiated descendants. The cambium, the stem cell niche mediating wood formation, fundamentally depends on auxin signalling but its exact role and spatial organization is obscure. Here we show that, while auxin signalling levels increase in differentiating cambium descendants, a moderate level of signalling in cambial stem cells is essential for cambium activity. We identify the auxin-dependent transcription factor ARF5/MONOPTEROS to cell-autonomously restrict the number of stem cells by directly attenuating the activity of the stem cell-promoting WOX4 gene. In contrast, ARF3 and ARF4 function as cambium activators in a redundant fashion from outside of WOX4-expressing cells. Our results reveal an influence of auxin signalling on distinct cambium features by specific signalling components and allow the conceptual integration of plant stem cell systems with distinct anatomies.

生长素信号的空间分布对于植物维持干细胞动态分化为子细胞具有非常重要的作用。形成层，干细胞龛介导木材形成，依赖于生长素信号转导，但其具体的作用和空间分布还不清楚。本文的研究显示生长素信号水平在形成层分化的子代细胞中增加，形成层干细胞中适当的生长素信号对于形成层活性是非常重要的。作者鉴定了一个生长素依赖性的转录因子ARF5/MONOPTEROS通过直接减弱干细胞促进因子WOX4基因的表达介导细胞自主性限制干细胞的数量。相反，ARF3和ARF4在表达WOX4基因的细胞外面做为形成层激活子发挥作用，且功能冗余。本文的研究揭示了生长素信号通过特定的信号元件影响形成层的特性，并能够将不同类型细胞和植物干细胞协调统一起来。

通讯：Thomas Greb (https://www.cos.uni-heidelberg.de/index.php/t.greb?l=_e)

研究方向：植物茎和根的径向生长。

doi: https://doi.org/10.1038/s41467-018-03256-2

Journal: Nature Communication

First Published: 28 February, 2018