Gene Silencing in Arabidopsis Spreads from the Root to the Shoot, through a Gating Barrier, by Template-Dependent, Nonvascular, Cell-to-Cell Movement
Gene Silencing in Arabidopsis Spreads from the Root to the Shoot, through a Gating Barrier, by Template-Dependent, Nonvascular, Cell-to-Cell Movement
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DOI：
10.1104/pp.112.197129
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发表时间：
2012-07-01
期刊：
影响因子：
7.4
通讯作者：
Waterhouse, Peter M.
中科院分区：
文献类型：
--
作者：
Liang, Dacheng;White, Rosemary G.;Waterhouse, Peter M.
向上长距离移动沉默已被证明是在几种不同的茄科物种中由韧皮部介导的。我们表明，拟南芥（Arabidopsis thaliana）幼苗嫁接系统和对应的诱导系统产生向上传播的长距离沉默，这种沉默不是在韧皮部中传播，而是通过模板依赖性的反复短距离细胞间传播穿过中央中柱的细胞。检查沉默前沿的运动揭示了顶端分生组织下方的一个很大程度上未被识别的组织区域，该区域对沉默信号具有抵抗力，并且可能提供针对小RNA信号的门控或保护屏障。使用一系列生长素和肌动蛋白转运抑制剂表明，在该区域，囊泡转运的改变以及细胞骨架动力学阻止或延缓了沉默信号的传播。这表明小RNA通过胞间连丝从一个细胞转运到另一个细胞，而不是从韧皮部的来源扩散。
Upward long-distance mobile silencing has been shown to be phloem mediated in several different solanaceous species. We show that the Arabidopsis (Arabidopsis thaliana) seedling grafting system and a counterpart inducible system generate upwardly spreading long-distance silencing that travels not in the phloem but by template-dependent reiterated short-distance cell-to-cell spread through the cells of the central stele. Examining the movement of the silencing front revealed a largely unrecognized zone of tissue, below the apical meristem, that is resistant to the silencing signal and that may provide a gating or protective barrier against small RNA signals. Using a range of auxin and actin transport inhibitors revealed that, in this zone, alteration of vesicular transport together with cytoskeleton dynamics prevented or retarded the spread of the silencing signal. This suggests that small RNAs are transported from cell to cell via plasmodesmata rather than diffusing from their source in the phloem.