Root system architecture from coupling cell shape to auxin transport.
Root system architecture from coupling cell shape to auxin transport.
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DOI：
10.1371/journal.pbio.0060307
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发表时间：
2008-12-16
期刊：
影响因子：
9.8
通讯作者：
Scheres B
中科院分区：
文献类型：
--
作者：
Laskowski M;Grieneisen VA;Hofhuis H;Hove CA;Hogeweg P;Marée AF;Scheres B
侧生器官沿着根和枝的位置在很大程度上决定了植物的构型，并取决于生长素的分布模式。迄今为止，确定潜在的图案化机制是复杂的，因为它们在生长和分裂期间起作用。在这里，我们通过实验和计算建模表明，拟南芥根的曲率影响细胞大小，这与组织特性，确定生长素运输，诱导更高的生长素水平在外廓细胞的曲线。生长素转运蛋白的丰度和位置限制了这种反应的区域主管侧根的形成。生长素输入促进剂AUX 1被生长素上调，导致额外的局部生长素输入，从而产生新的生长素最大值，触发器官形成。侧根的纵向间距是由PIN蛋白，促进生长素流出调制，和pin 2，3，7三重突变体显示受损的侧抑制。因此，侧根图案结合了一个触发器，如细胞大小的差异，由于弯曲，与自组织系统，介导的生长素运输的改变。植物的构型取决于沿着主轴的芽或根的形成位置，但侧根发生的机制长期以来一直困扰着生物学家。在这里，我们表明，伸展根细胞启动激素运输的变化，导致侧根在植物中的启动，从而解决了一个120年的谜团：侧根启动的机制。我们的数据显示，物理组织变形足以引起化学变化，释放生物反应，导致新器官形成。当根弯曲时，植物激素生长素的浓度沿着弯曲的外侧增加。产生复杂的生长素通量模式，其通过局部回流回路进一步提高生长素水平。生长素的输入者-AUX 1-和外排载体-PIN蛋白-已知受生长素调节。AUX 1的上调增强了生长素的最大值，该生长素的最大值指定了在弯曲处的侧根建立者细胞，而PIN的下调调节了根沿着主根轴的横向间距。这项研究表明，模式形成背后的生物调节可以是纠缠层次的结果，解释了内/外间距，侧抑制和侧根发生的动力学。实验数据和计算机模拟表明，侧根定位可以控制的物理刺激的根弯曲，引发自组织改变生长素运输。
Lateral organ position along roots and shoots largely determines plant architecture, and depends on auxin distribution patterns. Determination of the underlying patterning mechanisms has hitherto been complicated because they operate during growth and division. Here, we show by experiments and computational modeling that curvature of the Arabidopsis root influences cell sizes, which, together with tissue properties that determine auxin transport, induces higher auxin levels in the pericycle cells on the outside of the curve. The abundance and position of the auxin transporters restricts this response to the zone competent for lateral root formation. The auxin import facilitator, AUX1, is up-regulated by auxin, resulting in additional local auxin import, thus creating a new auxin maximum that triggers organ formation. Longitudinal spacing of lateral roots is modulated by PIN proteins that promote auxin efflux, and pin2,3,7 triple mutants show impaired lateral inhibition. Thus, lateral root patterning combines a trigger, such as cell size difference due to bending, with a self-organizing system that mediates alterations in auxin transport. Plant architecture is determined by where shoots or roots form along the main axis, but the mechanism responsible for lateral root initiation has long puzzled biologists. Here, we show that stretching root cells initiates changes in hormone transport, leading to lateral root initiation in plants, thereby solving a 120-year-old mystery: the mechanism of lateral root initiation. Our data reveal that physical tissue deformation is sufficient to induce chemical changes that unleash biological responses leading to new organ formation. When roots bend, concentrations of the plant hormone auxin increase along the outside of the bend. A complex auxin flux pattern is generated that further enhances auxin levels through localized reflux loops. Auxin importers—AUX1—and efflux carriers—PIN proteins—are known to be regulated by auxin. AUX1 up-regulation enhances the auxin maxima that specify the lateral root founder cells at the bend, while PIN down-regulation modulates the lateral spacing of the roots along the main root axis. This study shows that the biological regulation behind pattern formation can be a result of entangled hierarchies, explaining both the inner/outer spacing, lateral inhibition, and dynamics of lateral root initiation. Experimental data and computer modeling show that lateral root positioning can be controlled by the physical stimulus of root curvature, which triggers self-organizing alterations in auxin transport.
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