Laboratoire de Biogenèse Membranaire, UMR5200, CNRS, Université de Bordeaux, Villenave d'Ornon, France.
Bordeaux Imaging Center, UAR 3420, CNRS-INSERM-University of Bordeaux-INRAE, Bordeaux, France.
Science. 2024 Nov;386(6721):538-545. doi: 10.1126/science.adn4630. Epub 2024 Oct 31.
Diverging from conventional cell division models, plant cells undergo incomplete division to generate plasmodesmata communication bridges between daughter cells. Although fundamental for plant multicellularity, the molecular events leading to bridge stabilization, as opposed to severing, remain unknown. Using electron tomography, we mapped the transition from cell plate fenestrae to plasmodesmata. We show that the endoplasmic reticulum (ER) connects daughter cells across fenestrae, and as the cell plate matures, fenestrae contract, causing the plasma membrane (PM) to mold around constricted ER tubes. The ER's presence prevents fenestrae fusion, forming plasmodesmata, whereas its absence results in closure. The ER-PM protein tethers MCTP3, MCTP4, and MCTP6 further stabilize nascent plasmodesmata during fenestrae contraction. Genetic deletion in reduces plasmodesmata formation. Our findings reveal how plants undergo incomplete division to promote intercellular communication.
与传统的细胞分裂模式不同，植物细胞会进行不完全分裂，从而在子细胞之间产生胞间连丝通讯桥。尽管这对植物的多细胞性至关重要，但导致桥接稳定而不是切断的分子事件仍然未知。使用电子断层扫描技术，我们绘制了从细胞板窗格到胞间连丝的转变过程。我们表明，内质网（ER）将子细胞连接在窗格的两侧，随着细胞板的成熟，窗格收缩，导致质膜（PM）围绕收缩的 ER 管成型。ER 的存在阻止了窗格的融合，形成胞间连丝，而 ER 的缺失则导致其关闭。ER-PM 蛋白的连接蛋白 MCTP3、MCTP4 和 MCTP6 在窗格收缩过程中进一步稳定新形成的胞间连丝。缺失减少了胞间连丝的形成。我们的发现揭示了植物如何进行不完全分裂以促进细胞间通讯。
