State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
Plant Cell Environ. 2013 Feb;36(2):484-97. doi: 10.1111/j.1365-3040.2012.02592.x. Epub 2012 Sep 13.
The reorganization of actin filaments (AFs) and vacuoles in guard cells is involved in the regulation of stomatal movement. However, it remains unclear whether there is any interaction between the reorganization of AFs and vacuolar changes during stomatal movement. Here, we report the relationship between the reorganization of AFs and vacuolar fusion revealed in pharmacological experiments, and characterizing stomatal opening in actin-related protein 2 (arp2) and arp3 mutants. Our results show that cytochalasin-D-induced depolymerization or phalloidin-induced stabilization of AFs leads to an increase in small unfused vacuoles during stomatal opening in wild-type (WT) Arabidopsis plants. Light-induced stomatal opening is retarded and vacuolar fusion in guard cells is impaired in the mutants, in which the reorganization and the dynamic parameters of AFs are aberrant compared with those of the WT. In WT, AFs tightly surround the small separated vacuoles, forming a ring that encircles the boundary membranes of vacuoles partly fused during stomatal opening. In contrast, in the mutants, most AFs and actin patches accumulate abnormally around the nuclei of the guard cells, which probably further impair vacuolar fusion and retard stomatal opening. Our results suggest that the reorganization of AFs regulates vacuolar fusion in guard cells during stomatal opening.
肌动蛋白丝（AFs）和保卫细胞液泡的重排参与了气孔运动的调节。然而，AFs 的重排和气孔运动过程中液泡变化之间是否存在相互作用尚不清楚。在这里，我们报告了药理学实验中揭示的 AFs 重排与液泡融合之间的关系，并对肌动蛋白相关蛋白 2（arp2）和 arp3 突变体的气孔开放进行了特征描述。我们的结果表明，细胞松弛素 D 诱导的 AFs 解聚或鬼笔环肽诱导的稳定导致在野生型（WT）拟南芥植物气孔开放过程中小的未融合液泡增加。光诱导的气孔开放在突变体中受到阻滞，保卫细胞中的液泡融合受损，与 WT 相比，AFs 的重排和动态参数异常。在 WT 中，AFs 紧密包围小的分离液泡，形成一个环，环绕部分融合的液泡的边界膜。相比之下，在突变体中，大多数 AFs 和肌动蛋白斑点异常地积累在保卫细胞的核周围，这可能进一步损害液泡融合并延迟气孔开放。我们的结果表明，AFs 的重排调节了气孔开放过程中保卫细胞液泡的融合。
