Department of Experimental Plant Biology, Faculty of Science, Charles University, Vinicná, Czech Republic.
Institute of Experimental Botany, AS CR, Rozvojová, Czech Republic.
Ann Bot. 2018 Nov 3;122(5):777-789. doi: 10.1093/aob/mcx178.
The cytoskeleton plays an important role in the synthesis of plant cell walls. Both microtubules and actin cytoskeleton are known to be involved in the morphogenesis of plant cells through their role in cell wall building. The role of ARP2/3-nucleated actin cytoskeleton in the morphogenesis of cotyledon pavement cells has been described before. Seedlings of Arabidopsis mutants lacking a functional ARP2/3 complex display specific cell wall-associated defects.
In three independent Arabidopsis mutant lines lacking subunits of the ARP2/3 complex, phenotypes associated with the loss of the complex were analysed throughout plant development. Organ size and anatomy, cell wall composition, and auxin distribution were investigated.
ARP2/3-related phenotype is associated with changes in cell wall composition, and the phenotype is manifested especially in mature tissues. Cell walls of mature plants contain less cellulose and a higher amount of homogalacturonan, and display changes in cell wall lignification. Vascular bundles of mutant inflorescence stems show a changed pattern of AUX1-YFP expression. Plants lacking a functional ARP2/3 complex have decreased basipetal auxin transport.
The results suggest that the ARP2/3 complex has a morphogenetic function related to cell wall synthesis and auxin transport.
细胞骨架在植物细胞壁的合成中起着重要作用。众所周知，微管和肌动蛋白细胞骨架都通过在细胞壁构建中的作用参与植物细胞的形态发生。ARP2/3 核化肌动蛋白细胞骨架在子叶铺砌细胞形态发生中的作用以前已经被描述过。缺乏功能性 ARP2/3 复合物的拟南芥突变体幼苗表现出特定的与细胞壁相关的缺陷。
在三个缺乏 ARP2/3 复合物亚基的独立拟南芥突变系中，在整个植物发育过程中分析了与复合物缺失相关的表型。研究了器官大小和解剖结构、细胞壁组成和生长素分布。
与 ARP2/3 相关的表型与细胞壁组成的变化有关，该表型尤其表现在成熟组织中。成熟植物的细胞壁含有较少的纤维素和更多的同质半乳糖醛酸，并且显示出细胞壁木质素化的变化。突变体花序茎的维管束显示出 AUX1-YFP 表达模式的改变。缺乏功能性 ARP2/3 复合物的植物生长素的向基运输减少。
结果表明，ARP2/3 复合物具有与细胞壁合成和生长素运输相关的形态发生功能。
