Center for Frontier Research, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-Ku, Tokyo 113-0033, Japan.
Plant Cell. 2017 Dec;29(12):3123-3139. doi: 10.1105/tpc.17.00663. Epub 2017 Nov 13.
Proper patterning of the cell wall is essential for plant cell development. Cortical microtubule arrays direct the deposition patterns of cell walls at the plasma membrane. However, the precise mechanism underlying cortical microtubule organization is not well understood. Here, we show that a microtubule-associated protein, CORD1 (CORTICAL MICROTUBULE DISORDERING1), is required for the pitted secondary cell wall pattern of metaxylem vessels in Loss of and its paralog, , led to the formation of irregular secondary cell walls with small pits in metaxylem vessels, while overexpressing led to the formation of abnormally enlarged secondary cell wall pits. Ectopic expression of disturbed the parallel cortical microtubule array by promoting the detachment of microtubules from the plasma membrane. A reconstructive approach revealed that CORD1-induced disorganization of cortical microtubules impairs the boundaries of plasma membrane domains of active ROP11 GTPase, which govern pit formation. Our data suggest that CORD1 promotes cortical microtubule disorganization to regulate secondary cell wall pit formation. The Arabidopsis genome has six paralogs that are expressed in various tissues during plant development, suggesting they are important for regulating cortical microtubules during plant development.
细胞壁的正确模式对于植物细胞的发育至关重要。皮层微管阵列指导质膜处细胞壁的沉积模式。然而，皮层微管组织的精确机制尚不清楚。在这里，我们表明微管相关蛋白 CORD1（皮层微管紊乱 1）对于木质部导管的凹陷次生细胞壁模式是必需的。CORD1 的缺失及其同源物 导致木质部导管中出现不规则的次生细胞壁和小凹陷，而过表达 则导致次生细胞壁凹陷异常增大。异位表达 通过促进微管从质膜上脱离，扰乱了平行的皮层微管阵列。重建方法表明，CORD1 诱导的皮层微管解聚会损害 ROP11 GTPase 活性的质膜域边界，而 ROP11 GTPase 控制凹陷的形成。我们的数据表明，CORD1 促进皮层微管解聚以调节次生细胞壁凹陷的形成。拟南芥基因组有六个 同源物，它们在植物发育的不同组织中表达，这表明它们在植物发育过程中对于调节皮层微管很重要。
