Chi Zhihai, Ambrose Chris
Department of Biology, The University of Saskatchewan, College of Arts and Science, Saskatoon, Canada.
State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2025 Sep 8;20(9):e0325015. doi: 10.1371/journal.pone.0325015. eCollection 2025.
Plasmodesmata are specialized structures in plant cell walls that mediate intercellular communication by regulating the trafficking of molecules between adjacent cells. The actin cytoskeleton plays a pivotal role in controlling plasmodesmatal permeability, but the molecular mechanisms underlying this regulation remain unclear. Here, we report that BRK1, a component of the WAVE/SCAR complex involved in Arp2/3-mediated actin nucleation, localizes to PD and primary pit fields in A. thaliana cotyledons, leaves, and hypocotyls. Using a BRK1-YFP reporter line, we detected BRK1 enrichment at cell edges and in primary pit fields, identified by regions of reduced propidium iodide staining. We also observed colocalization between BRK1-YFP and the plasmodesmatal callose stain aniline blue, further supporting BRK1's association with Plasmodesmata. Together, these findings suggest that the WAVE/SCAR complex participates in plasmodesmatal regulation by promoting ARP2/3-dependent actin filament branching at plasmodesmata, complementing the role of linear actin stabilization by formins.
胞间连丝是植物细胞壁中的特殊结构，通过调节相邻细胞间分子的运输来介导细胞间通讯。肌动蛋白细胞骨架在控制胞间连丝通透性方面起着关键作用，但这种调节的分子机制仍不清楚。在这里，我们报道BRK1，一种参与Arp2/3介导的肌动蛋白成核的WAVE/SCAR复合体的组分，定位于拟南芥子叶、叶片和下胚轴的胞间连丝和初生纹孔场。使用BRK1-YFP报告株系，我们在细胞边缘和初生纹孔场检测到BRK1富集，初生纹孔场由碘化丙啶染色减少的区域确定。我们还观察到BRK1-YFP与胞间连丝胼胝质染料苯胺蓝的共定位，进一步支持BRK1与胞间连丝的关联。总之，这些发现表明WAVE/SCAR复合体通过促进胞间连丝处ARP2/3依赖的肌动蛋白丝分支参与胞间连丝调节，补充了formin对线性肌动蛋白稳定的作用。
