A Mutually Inhibitory Interaction between Auxin and Cytokinin Specifies Vascular Pattern in Roots
A Mutually Inhibitory Interaction between Auxin and Cytokinin Specifies Vascular Pattern in Roots
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DOI：
10.1016/j.cub.2011.04.017
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发表时间：
2011-06-07
期刊：
影响因子：
9.2
通讯作者：
Helariutta, Yka
中科院分区：
文献类型：
--
作者：
Bishopp, Anthony;Help, Hanna;Helariutta, Yka
背景资料：尽管大多数动物朝着预定的身体计划发展，但植物表现出迭代生长，并从活跃的分生组织中不断产生新的器官和结构。这提出了一个有趣的问题：这些新发育的器官是如何形成的？在拟南芥胚胎中，径向对称性被破坏的子叶在顶端域的双对称规格。随后，这种bisymmetry传播到根promeristem.Results：在这里，我们提出了生长素和细胞分裂素之间的相互抑制的反馈回路，设置不同的激素输出的边界。细胞分裂素促进PIN形成的（PIN）生长素流出蛋白的双对称分布，其将生长素引导到中心结构域。高生长素促进细胞分裂素信号抑制剂AHP6的转录，从而关闭相互作用环。这双对称生长素反应域指定的分化原生木质部的双对称模式。在胚胎根，细胞分裂素是需要翻译的bisymmetric生长素的反应在子叶中的bisymmetric血管图案在根promeristem.Conclusions：我们的研究结果提出了一个相互作用的反馈回路激素信号和运输的激素输入的小偏见传播到不同的信号域指定的血管图案在根分生组织。这是一个有趣的可能性，这种机制可以改变放射状模式，并允许其他新出现的器官之间的连续血管连接。
Background: Whereas the majority of animals develop toward a predetermined body plan, plants show iterative growth and continually produce new organs and structures from actively dividing meristems. This raises an intriguing question: How are these newly developed organs patterned? In Arabidopsis embryos, radial symmetry is broken by the bisymmetric specification of the cotyledons in the apical domain. Subsequently, this bisymmetry is propagated to the root promeristem.Results: Here we present a mutually inhibitory feedback loop between auxin and cytokinin that sets distinct boundaries of hormonal output. Cytokinins promote the bisymmetric distribution of the PIN-FORMED (PIN) auxin efflux proteins, which channel auxin toward a central domain. High auxin promotes transcription of the cytokinin signaling inhibitor AHP6, which closes the interaction loop. This bisymmetric auxin response domain specifies the differentiation of protoxylem in a bisymmetric pattern. In embryonic roots, cytokinin is required to translate a bisymmetric auxin response in the cotyledons to a bisymmetric vascular pattern in the root promeristem.Conclusions: Our results present an interactive feedback loop between hormonal signaling and transport by which small biases in hormonal input are propagated into distinct signaling domains to specify the vascular pattern in the root meristem. It is an intriguing possibility that such a mechanism could transform radial patterns and allow continuous vascular connections between other newly emerging organs.