Plant stems comprise nodes and internodes that specialize in solute exchange and elongation. However, their boundaries are not well defined, and how these basic units arise remains elusive. In rice with clear nodes and internodes, we found that one subclade of class I knotted1-like homeobox ( KNOX1 ) genes for shoot meristem indeterminacy restricts node differentiation and allows internode formation by repressing YABBY genes for leaf development and genes from another node-specific KNOX1 subclade. YABBY s promote nodal vascular differentiation and limit stem elongation. YABBY and node-specific KNOX1 genes specify the pulvinus, which further elaborates the nodal structure for gravitropism. Notably, this KNOX1 subclade organization is specific to seed plants. We propose that nodes and internodes are distinct domains specified by YABBY – KNOX1 cross-regulation that diverged in early seed plants.

中文翻译：

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YABBY 和分化的 KNOX1 基因塑造茎中的节和节间


植物茎包括专门从事溶质交换和伸长的节和节间。然而，它们的边界并没有明确界定，这些基本单位是如何产生的仍然难以捉摸。在具有清晰节和节间的水稻中，我们发现 I 类的一个分支结1样同源框（诺克斯1 ）茎分生组织不确定性的基因限制节分化并通过抑制允许节间形成雅比叶子发育的基因和来自另一个特定节点的基因诺克斯1亚支。雅比促进淋巴结血管分化并限制茎伸长。雅比和特定于节点的诺克斯1基因指定了枕骨，进一步阐述了向地性的节点结构。值得注意的是，这诺克斯1支系组织是种子植物特有的。我们建议节点和节点间是由以下指定的不同域雅比–诺克斯1交叉调节在早期种子植物中有所不同。