Environmental regulation of lateral root initiation in Arabidopsis
Environmental regulation of lateral root initiation in Arabidopsis
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DOI：
10.1104/pp.010406
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发表时间：
2001-11-01
期刊：
影响因子：
7.4
通讯作者：
Ryan, KS
中科院分区：
文献类型：
--
作者：
Malamy, JE;Ryan, KS
植物的形态受到环境信号的显著影响。根系的生长和发育是这种发育可塑性的一个很好的例子。侧根的数量和位置对营养线索都有很高的反应。这表明，一定有一条信号转导通路，解释复杂的环境条件，并在特定的时间和地点做出形成侧根的“决定”。侧根起源于成体组织中的分化细胞。这些细胞必须重新进入细胞周期，增殖和再分化，以产生构成新器官的所有细胞类型。侧根的发生是如何受生长条件的调控或协调的，目前几乎还不清楚。在这里，我们报告了一种新的生长测定，允许这种调节机制在拟南芥被解剖。当拟南芥幼苗生长在高蔗糖氮比的营养培养基上时，侧根的发生被显著抑制。生长素定位似乎是这种营养介导的抑制侧根发生的关键因素。我们已经分离出一个突变体，侧根起始1（林1），克服了压抑的条件。该突变体在高蔗糖氮比的培养基上产生高度分枝的根系。lin1表型是特定于这些生长条件，这表明lin1基因参与协调侧根发生与营养线索。因此，这些研究提供了新的见解的机制，调节侧根发生的最早的步骤，并协调植物发育与环境。
Plant morphology is dramatically influenced by environmental signals. The growth and development of the root system is an excellent example of this developmental plasticity. Both the number and placement of lateral roots are highly responsive to nutritional cues. This indicates that there must be a signal transduction pathway that interprets complex environmental conditions and makes the "decision" to form a lateral root at a particular time and place. Lateral roots originate from differentiated cells in adult tissues. These cells must reenter the cell cycle, proliferate, and redifferentiate to produce all of the cell types that make up a new organ. Almost nothing is known about how lateral root initiation is regulated or coordinated with growth conditions. Here, we report a novel growth assay that allows this regulatory mechanism to be dissected in Arabidopsis. When Arabidopsis seedlings are grown on nutrient media with a high sucrose to nitrogen ratio, lateral root initiation is dramatically repressed. Auxin localization appears to be a key factor in this nutrient-mediated repression of lateral root initiation. We have isolated a mutant, lateral root initiation 1 (lin1), that overcomes the repressive conditions. This mutant produces a highly branched root system on media with high sucrose to nitrogen ratios. The lin1 phenotype is specific to these growth conditions, suggesting that the lin1 gene is involved in coordinating lateral root initiation with nutritional cues. Therefore, these studies provide novel insights into the mechanisms that regulate the earliest steps in lateral root initiation and that coordinate plant development with the environment.