Auxin influx carriers stabilize phyllotactic patterning
Auxin influx carriers stabilize phyllotactic patterning
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DOI：
10.1101/gad.462608
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发表时间：
2008-03-15
影响因子：
10.5
通讯作者：
Kuhlemeier, Cris
中科院分区：
文献类型：
--
作者：
Bainbridge, Katherine;Guyomarc'h, Soazig;Kuhlemeier, Cris
植物结构最显著的特征之一是叶和花围绕茎的规则排列，称为叶序。植物激素生长素浓度的峰值，由PIN1生长素流出载体的极性定位产生，为原基起始提供指导信号。这种机制产生相邻原基之间的间距，这导致规则的叶序。生长素运输在叶序格局中的作用的研究集中在PIN1介导的外排。最近的计算机模拟表明，运输介导的生长素摄取的额外作用。然而，还没有报道AUX 1生长素流入载体中的突变会引起气生表型。在这里，我们研究了AUX 1及其旁系同源物LAX1，LAX2和LAX3的作用。四倍体突变体的分析揭示连续原基之间的不规则发散角。表型的一个非常不寻常的方面是原基簇的出现，违反了经典理论。在分子水平上，生长素水平的尖峰和协调的PIN极化减少或消失。此外，在短日照条件下表型的增加的迁移率表明AUX LAX转运蛋白起缓冲PIN介导的图案化机制以对抗环境或发育影响的作用。
One of the most striking features of plant architecture is the regular arrangement of leaves and flowers around the stem, known as phyllotaxis. Peaks in concentration of the plant hormone auxin, generated by the polar localization of the PIN1 auxin efflux carrier, provide the instructive signal for primordium initiation. This mechanism generates the spacing between neighboring primordia, which results in regular phyllotaxis. Studies of the role of auxin transport in phyllotactic patterning have focused on PIN1-mediated efflux. Recent computer simulations indicate an additional role for transporter-mediated auxin uptake. Mutations in the AUX1 auxin influx carrier have not, however, been reported to cause an aerial phenotype. Here, we study the role of AUX1 and its paralogs LAX1, LAX2, and LAX3. Analysis of the quadruple mutant reveals irregular divergence angles between successive primordia. A highly unusual aspect of the phenotype is the occurrence of clusters of primordia, in violation of classical theory. At the molecular level, the sharp peaks in auxin levels and coordinated PIN polarization are reduced or lost. In addition, the increased penetrance of the phenotype under short-day conditions suggests that the AUX LAX transporters act to buffer the PIN-mediated patterning mechanism against environmental or developmental influences.