Cytokinin regulates root meristem activity via modulation of the polar auxin transport
Cytokinin regulates root meristem activity via modulation of the polar auxin transport
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DOI：
10.1073/pnas.0900060106
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发表时间：
2009-03-17
影响因子：
11.1
通讯作者：
Benkova, Eva
中科院分区：
文献类型：
--
作者：
Ruzicka, Kamil;Simaskova, Maria;Benkova, Eva
植物的发育受称为植物激素的信号分子控制。通常，在某些发育过程中，涉及超过1种激素，因此，它们的重叠活动的协调对于正确的植物发育至关重要。然而，激素串扰的分子机制还知之甚少。包括细胞分裂素和生长素在内的多种激素都参与了根发育的调节。在这里，我们剖析的作用，细胞分裂素在调节生长的主根。我们发现，细胞分裂素对根伸长的影响发生通过乙烯信号，而细胞分裂素对根分生组织大小的影响涉及乙烯的非依赖性调节运输依赖的不对称生长素分布。细胞分裂素水平和细胞分裂素信号传导的外源或内源修饰导致来自PIN家族的几种生长素流出载体基因的转录的特异性变化，其对生长素从培养细胞流出和生长素在根尖中的分布具有直接影响。我们提出了一个新的模型细胞分裂素的行动在调节根的生长：细胞分裂素的影响细胞到细胞的生长素运输的几个生长素运输组件的表达的修改，从而调制生长素的分布重要的活性和大小的根分生组织的调节。
Plant development is governed by signaling molecules called phytohormones. Typically, in certain developmental processes more than 1 hormone is implicated and, thus, coordination of their overlapping activities is crucial for correct plant development. However, molecular mechanisms underlying the hormonal crosstalk are only poorly understood. Multiple hormones including cytokinin and auxin have been implicated in the regulation of root development. Here we dissect the roles of cytokinin in modulating growth of the primary root. We show that cytokinin effect on root elongation occurs through ethylene signaling whereas cytokinin effect on the root meristem size involves ethylene-independent modulation of transport-dependent asymmetric auxin distribution. Exogenous or endogenous modification of cytokinin levels and cytokinin signaling lead to specific changes in transcription of several auxin efflux carrier genes from the PIN family having a direct impact on auxin efflux from cultured cells and on auxin distribution in the root apex. We propose a novel model for cytokinin action in regulating root growth: Cytokinin influences cell-to-cell auxin transport by modification of expression of several auxin transport components and thus modulates auxin distribution important for regulation of activity and size of the root meristem.