Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Korea.
Mol Cells. 2010 Aug;30(2):113-9. doi: 10.1007/s10059-010-0095-y. Epub 2010 Jul 23.
Development of the vascular tissues is a dynamic process that integrates extrinsic and intrinsic factors to control vascular tissue formation throughout the plant life cycle. During vascular tissue formation in Arabidopsis roots, radial and longitudinal signals, including nuclear factors and plant hormones, control the developmental processes involved in the specification, differentiation, and maintenance of the correct cell types. SHR, a GRAS transcription factor, has been known to regulate the specification of the stem cell niche and ground tissue identity in the root meristem in a non-cell-autonomous manner. However, the role of SHR in the root vasculature is relatively overlooked, despite localization of its mRNA and protein in the stele. Here, we investigated the role of SHR in the vascular system of the primary root using a reverse genetic approach and detailed phenotypic analysis. A novel, loss-of-function null mutant, shr-6, was isolated in the Columbia background, and vascular patterning was characterized in detail. Our results reveal that shr mutants have developmental defects in both protophloem and protoxylem elements. Our study also suggests that SHR plays a central role in the root vascular system to control patterning processes, possibly regulated by longitudinal and radial signals.
血管组织的发育是一个动态的过程，它整合了外在和内在因素，以控制植物整个生命周期中的血管组织形成。在拟南芥根中的血管组织形成过程中，包括核因子和植物激素在内的径向和纵向信号，控制着参与特定细胞类型的指定、分化和维持的发育过程。SHR 是一种 GRAS 转录因子，它被认为以非细胞自主的方式调节根分生组织中干细胞龛和基础组织身份的指定。然而，尽管 SHR 的 mRNA 和蛋白质在中柱中定位，但它在根脉管系统中的作用相对被忽视。在这里，我们使用反向遗传学方法和详细的表型分析研究了 SHR 在主根血管系统中的作用。在哥伦比亚背景下分离出一种新型的功能丧失型 null 突变体 shr-6，并详细描述了其血管模式。我们的结果表明 shr 突变体在原韧皮部和原木质部元素中都有发育缺陷。我们的研究还表明，SHR 在根脉管系统中发挥着核心作用，以控制模式形成过程，可能受到纵向和径向信号的调节。
