Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
Department of Plant Molecular Biology, University of Lausanne, CH-1015, Lausanne, Switzerland.
Proc Natl Acad Sci U S A. 2020 Dec 22;117(51):32750-32756. doi: 10.1073/pnas.2018565117. Epub 2020 Dec 7.
Cell division is often regulated by extracellular signaling networks to ensure correct patterning during development. In , the SHORT-ROOT (SHR)/SCARECROW (SCR) transcription factor dimer activates ; () to drive formative divisions during root ground tissue development. Here, we show plasma-membrane-localized BARELY ANY MERISTEM1/2 (BAM1/2) family receptor kinases are required for -dependent formative divisions and expression, but not -dependent ground tissue specification. Root-enriched CLE ligands bind the BAM1 extracellular domain and are necessary and sufficient to activate -mediated divisions and expression. Correspondingly, BAM-CLE signaling contributes to the restriction of formative divisions to the distal root region. Additionally, genetic analysis reveals that BAM-CLE and SHR converge to regulate additional cell divisions outside of the ground tissues. Our work identifies an extracellular signaling pathway regulating formative root divisions and provides a framework to explore this pathway in patterning and evolution.
细胞分裂通常受到细胞外信号网络的调节，以确保在发育过程中的正确模式形成。在这里，SHORT-ROOT（SHR）/SCARECROW（SCR）转录因子二聚体激活（），以驱动根基本组织发育过程中的形成性分裂。在这里，我们表明质膜定位的 BARELY ANY MERISTEM1/2（BAM1/2）家族受体激酶对于 - 依赖性形成性分裂和 表达是必需的，但对于 - 依赖性基本组织特化不是必需的。根富集的 CLE 配体结合 BAM1 细胞外结构域，并且是激活 - 介导的分裂和 表达所必需且充分的。相应地，BAM-CLE 信号传导有助于将形成性分裂限制在根的远侧区域。此外，遗传分析表明 BAM-CLE 和 SHR 收敛以调节基本组织外的其他细胞分裂。我们的工作确定了一个调节形成性根分裂的细胞外信号通路，并为探索该通路在模式形成和进化中的作用提供了一个框架。
