Microtubules regulate tip growth and orientation in root hairs of Arabidopsis thaliana
Microtubules regulate tip growth and orientation in root hairs of Arabidopsis thaliana
复制标题
DOI：
10.1046/j.1365-313x.1999.00415.x
复制
发表时间：
1999-03-01
期刊：
影响因子：
7.2
通讯作者：
Gilroy, S
中科院分区：
文献类型：
--
作者：
Bibikova, TN;Blancaflor, EB;Gilroy, S
真菌菌丝、花粉管、藻类假根和根毛等多种细胞的极化生长的特征是细胞扩展的高度局部化调节局限于生长尖端。在顶端生长的植物细胞中，尖端聚焦的[Ca 2 +]（c）梯度和细胞骨架与生长相关。虽然肌动蛋白已被确定为是必不可少的延长的维持，微管的作用仍然不清楚。为了解决微管细胞骨架是否参与根毛的生长和方向，我们应用微管拮抗剂拟南芥根毛。在这份报告中，我们表明，解聚或稳定这些顶端生长的根毛的微管细胞骨架，导致失去方向性的增长和形成多个，独立的生长点在一个单一的根毛。每个生长点含有[Ca 2 +]（c）的尖端聚焦梯度。实验生成一个新的[Ca 2 +]（c），梯度在用微管拮抗剂预处理的根毛中，使用笼状钙离子载体Br-A23187，能够诱导形成一个新的生长点的网站上的钙离子流入升高。这些数据表明微管在调节根毛顶端生长的方向性和稳定性中的作用。此外，这些结果表明，微管的作用可能是通过与细胞机制的相互作用来介导的，细胞机制维持了尖端的[Ca 2 +]（c）梯度。
The polarized growth of cells as diverse as fungal hyphae, pollen tubes, algal rhizoids and root hairs is characterized by a highly localized regulation of cell expansion confined to the growing tip. In apically growing plant cells, a tip-focused [Ca2+](c) gradient and the cytoskeleton have been associated with growth. Although actin has been established to be essential for the maintenance of elongation, the role of microtubules remains unclear. To address whether the microtubule cytoskeleton is involved in root hair growth and orientation, we applied microtubule antagonists to root hairs of Arabidopsis. In this report, we show that depolymerizing or stabilizing the microtubule cytoskeleton of these apically growing root hairs led to a loss of directionality of growth and the formation of multiple, independent growth points in a single root hair. Each growing point contained a tip-focused gradient of [Ca2+](c). Experimental generation of a new [Ca2+](c), gradient in root hairs pre-treated with microtubule antagonists, using the caged-calcium ionophore Br-A23187, was capable of inducing the formation of a new growth point at the site of elevated calcium influx. These data indicate a role for microtubules in regulating the directionality and stability of apical growth in root hairs. In addition, these results suggest that the action of the microtubules may be mediated through interactions with the cellular machinery that maintains the [Ca2+](c) gradient at the tip.