1] Cell Biology Division, Department of Biology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany [2].
1] Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki FIN-00014, Finland [2].
Nat Commun. 2014 Jul 10;5:4276. doi: 10.1038/ncomms5276.
Phloem, a plant tissue responsible for long-distance molecular transport, harbours specific junctions, sieve areas, between the conducting cells. To date, little is known about the molecular framework related to the biogenesis of these sieve areas. Here we identify mutations at the CHER1/AtCTL1 locus of Arabidopsis thaliana. The mutations cause several phenotypic abnormalities, including reduced pore density and altered pore structure in the sieve areas associated with impaired phloem function. CHER1 encodes a member of a poorly characterized choline transporter-like protein family in plants and animals. We show that CHER1 facilitates choline transport, localizes to the trans-Golgi network, and during cytokinesis is associated with the phragmoplast. Consistent with its function in the elaboration of the sieve areas, CHER1 has a sustained, polar localization in the forming sieve plates. Our results indicate that the regulation of choline levels is crucial for phloem development and conductivity in plants.
韧皮部是负责长距离分子运输的植物组织，其中存在着特定的连接结构——筛管区域，位于传导细胞之间。迄今为止，人们对与这些筛管区域生物发生相关的分子框架知之甚少。在这里，我们鉴定了拟南芥 CHER1/AtCTL1 基因座的突变。这些突变导致了几种表型异常，包括筛管区域中孔隙密度降低和结构改变，从而影响韧皮部功能。CHER1 编码植物和动物中胆碱转运体样蛋白家族中一个特征不明显的成员。我们表明，CHER1 促进胆碱转运，定位于反式高尔基体网络，并在胞质分裂期间与成膜体相关。与其在筛管区域形成中的作用一致，CHER1 在形成的筛板中具有持续的极性定位。我们的结果表明，胆碱水平的调节对植物韧皮部发育和导性至关重要。
