Group of Plant Vascular Development, Swiss Federal Institute of Technology (ETH) Zurich, 8092 Zurich, Switzerland.
Group of Phloem Development, Swiss Federal Institute of Technology (ETH) Zurich, 8092 Zurich, Switzerland.
Curr Biol. 2020 Mar 9;30(5):755-766.e4. doi: 10.1016/j.cub.2019.12.043. Epub 2020 Feb 6.
Plant cells can change their identity based on positional information, a mechanism that confers developmental plasticity to plants. This ability, common to distinct multicellular organisms, is particularly relevant for plant phloem cells. Protophloem sieve elements (PSEs), one type of phloem conductive cells, act as the main organizers of the phloem pole, which comprises four distinct cell files organized in a conserved pattern. Here, we report how Arabidopsis roots generate a reservoir of meristematic phloem cells competent to swap their cell identities. Although PSE misspecification induces cell identity hybridism, the activity of RECEPTOR LIKE PROTEIN KINASE 2 (RPK2) by perceiving CLE45 peptide contributes to restrict PSE identity to the PSE position. By maintaining a spatiotemporal window when PSE and PSE-adjacent cells' identities are interchangeable, CLE45 signaling endows phloem cells with the competence to re-pattern a functional phloem pole when protophloem fails to form.
植物细胞可以根据位置信息改变其身份，这种机制赋予了植物发育可塑性。这种能力在不同的多细胞生物中很常见，对植物韧皮部细胞尤为重要。原韧皮部筛分子（PSEs）是一种韧皮部传导细胞，作为韧皮部极点的主要组织者，韧皮部极点由四个按保守模式组织的不同细胞层组成。在这里，我们报告了拟南芥根如何产生一个具有交换细胞身份能力的分生组织韧皮部细胞库。尽管 PSE 错位会诱导细胞身份混合，但通过感知 CLE45 肽，受体样蛋白激酶 2（RPK2）的活性有助于将 PSE 身份限制在 PSE 位置。通过维持 PSE 和 PSE 相邻细胞身份可互换的时空窗口，CLE45 信号赋予韧皮部细胞在原韧皮部不能形成时重新形成功能韧皮部极点的能力。
