Subdomains for transport via plasmodesmata corresponding to the apical-basal axis are established during Arabidopsis embryogenesis
Subdomains for transport via plasmodesmata corresponding to the apical-basal axis are established during Arabidopsis embryogenesis
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DOI：
10.1073/pnas.0505622102
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发表时间：
2005-08-16
影响因子：
11.1
通讯作者：
Zambryski, PC
中科院分区：
文献类型：
--
作者：
Kim, I;Kobayashi, K;Zambryski, PC
拟南芥胚胎发育过程中，生长素信号和差异基因表达决定了拟南芥的轴向体模式。在这里，我们证明了另一种途径，细胞间的沟通，通过胞间连丝（PD），在顶端-基底图案的形成过程中进行调节。SHOOT MERISTEMLESS（STM）启动子用于驱动1 ×、2 ×和3 ×可溶性绿色荧光蛋白（sGFP）和与1 ×和2 × sGFP特异性融合的烟草花叶病毒（TMV）的P30运动蛋白在茎顶端分生组织（SAM）和下胚轴基部的细胞亚群中的表达。在早期心脏阶段，2X sGFP（54 kDa）在整个胚胎中移动，而3X sGFP（81 kDa）显示出更受限制的移动。随着胚胎的发育，PD孔被下调以形成局部子域，从而允许不同大小的示踪剂的运输。例如，2x sGFP向子叶的移动和3X sGFP向根尖的移动受到限制。细胞到细胞运输的亚结构域与顶端-基部胚体轴对齐，并对应于茎尖、子叶、下胚轴和根。P30-GFP融合的研究加强了胚胎共质体亚结构域之间的区别。虽然P30的目标是胚胎细胞壁作为puncta（诊断功能定位的P30 PD在成年植物），P30不能扩张胚胎PD克服共质体亚域之间的运输障碍，这表明特定的边界分离共质体亚域的胚胎。因此，细胞与细胞之间的通讯通过胞间连丝传递的位置信息，在拟南芥胚胎发生过程中建立轴体模式至关重要。
The axial body pattern of Arabidopsis is determined during embryogenesis by auxin signaling and differential gene expression. Here we demonstrate that another pathway, cell-to-cell communication through plasmodesmata (PD), is regulated during apical-basal pattern formation. The SHOOT MERISTEMLESS (STM) promoter was used to drive expression in the shoot apical meristem (SAM) and a subset of cells at the base of the hypocotyl of 1 x, 2x, and 3x soluble green fluorescent proteins (sGFPs), and the P30 movement protein of Tobacco mosaic virus (TMV) translationally fused to 1 x and 2x sGFP. In the early heart stage, 2X sGFP (54 kDa) moves throughout the whole embryo, whereas 3x sGFP (81 kDa) shows more restricted movement. As the embryo develops, PD apertures are down regulated to form local subdomains allowing transport of different sized tracers. For example, movement of 2 x sGFP to the cotyledon, and 3X sGFP to root tips, becomes restricted. Subdomains of cell-to-cell transport align with the apical-basal embryo body axis and correspond to the shoot apex, cotyledons, hypocotyl, and root. Studies with P30-GFP fusions reinforce the distinction between embryonic symplastic subdomains. Although P30 targets embryo cell walls as puncta (diagnostic for functional localization of P30 to PD in adult plants), P30 cannot dilate embryonic PD to overcome the barriers for transport between symplastic subdomains, suggesting that specific boundaries separate symplastic subdomains of the embryo. Thus, cell-to-cell communication via plasmodesmata conveys positional information critical to establish the axial body pattern during embryogenesis in Arabidopsis.