Hazak Ora, Brandt Benjamin, Cattaneo Pietro, Santiago Julia, Rodriguez-Villalon Antia, Hothorn Michael, Hardtke Christian S
Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland.
Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland.
EMBO Rep. 2017 Aug;18(8):1367-1381. doi: 10.15252/embr.201643535. Epub 2017 Jun 12.
root development is orchestrated by signaling pathways that consist of different CLAVATA3/EMBRYO SURROUNDING REGION (CLE) peptide ligands and their cognate CLAVATA (CLV) and BARELY ANY MERISTEM (BAM) receptors. How and where different CLE peptides trigger specific morphological or physiological changes in the root is poorly understood. Here, we report that the receptor-like protein CLAVATA 2 (CLV2) and the pseudokinase CORYNE (CRN) are necessary to fully sense root-active CLE peptides. We uncover BAM3 as the CLE45 receptor in the root and biochemically map its peptide binding surface. In contrast to other plant peptide receptors, we found no evidence that SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) proteins act as co-receptor kinases in CLE45 perception. CRN stabilizes BAM3 expression and thus is required for BAM3-mediated CLE45 signaling. Moreover, protophloem-specific expression complements resistance of the mutant to root-active CLE peptides, suggesting that protophloem is their principal site of action. Our work defines a genetic framework for dissecting CLE peptide signaling and CLV/BAM receptor activation in the root.
根的发育由信号通路精心调控，这些信号通路由不同的CLAVATA3/胚周围区域（CLE）肽配体及其同源的CLAVATA（CLV）和几乎无分生组织（BAM）受体组成。不同的CLE肽如何以及在何处触发根中特定的形态或生理变化，目前还知之甚少。在这里，我们报告受体样蛋白CLAVATA 2（CLV2）和假激酶CORYNE（CRN）对于充分感知根活性CLE肽是必需的。我们发现BAM3是根中CLE45的受体，并通过生化方法绘制了其肽结合表面。与其他植物肽受体不同，我们没有发现体细胞胚胎发生受体激酶（SERK）蛋白在CLE45感知中作为共受体激酶起作用的证据。CRN稳定BAM3的表达，因此是BAM3介导的CLE45信号传导所必需的。此外，原生韧皮部特异性表达补充了突变体对根活性CLE肽的抗性，表明原生韧皮部是它们的主要作用部位。我们的工作定义了一个遗传框架，用于剖析根中CLE肽信号传导和CLV/BAM受体激活。
