Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Mol Plant. 2015 Apr;8(4):612-21. doi: 10.1016/j.molp.2014.10.008. Epub 2014 Dec 13.
During vascular development, procambial and cambial cells give rise to xylem and phloem cells. Because the vascular tissue is deeply embedded, it has been difficult to analyze the processes of vascular development in detail. Here, we establish a novel in vitro experimental system in which vascular development is induced in Arabidopsis thaliana leaf-disk cultures using bikinin, an inhibitor of glycogen synthase kinase 3 proteins. Transcriptome analysis reveals that mesophyll cells in leaf disks synchronously turn into procambial cells and then differentiate into tracheary elements. Leaf-disk cultures from plants expressing the procambial cell markers TDR(pro):GUS and TDR(pro):YFP can be used for spatiotemporal visualization of procambial cell formation. Further analysis with the tdr mutant and TDIF (tracheary element differentiation inhibitory factor) indicates that the key signaling TDIF-TDR-GSK3s regulates xylem differentiation in leaf-disk cultures. This new culture system can be combined with analysis using the rich material resources for Arabidopsis including cell-marker lines and mutants, thus offering a powerful tool for analyzing xylem cell differentiation.
在血管发育过程中，原形成层和形成层细胞分别产生木质部和韧皮部细胞。由于维管束组织深埋在植物体内，因此很难对其发育过程进行详细分析。在这里，我们建立了一种新的体外实验系统，利用 bikinin（一种糖原合成激酶 3 蛋白抑制剂）诱导拟南芥叶片圆盘培养物中的血管发育。转录组分析表明，叶片圆盘的叶肉细胞同步转变为原形成层细胞，然后分化为导管分子。表达原形成层细胞标记物 TDR(pro):GUS 和 TDR(pro):YFP 的植株叶片圆盘培养物可用于原形成层细胞形成的时空可视化。对 tdr 突变体和 TDIF（导管分化抑制因子）的进一步分析表明，关键信号 TDIF-TDR-GSK3s 调控叶片圆盘培养物中的木质部分化。这种新的培养系统可以与拟南芥丰富的材料资源（包括细胞标记系和突变体）相结合，为分析木质部细胞分化提供了有力工具。
