Automated analysis of hypocotyl growth dynamics during shade avoidance in Arabidopsis.
Automated analysis of hypocotyl growth dynamics during shade avoidance in Arabidopsis.
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DOI：
10.1111/j.1365-313x.2010.04476.x
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发表时间：
2011-03
期刊：
影响因子：
--
通讯作者：
Chory J
中科院分区：
文献类型：
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作者：
Cole B;Kay SA;Chory J
适应光照充足环境的植物对来自邻近植被的光竞争特别敏感。因此，这些植物开始了一系列被称为避荫综合征的变化，在此期间，植物以牺牲叶片发育为代价延长其茎和叶柄。虽然暴露在长时间荫蔽下的发育结果是已知的，但幼苗最初暴露在荫蔽下的信号动力学研究较少。在这里，我们报告了一种新的基于软件的工具，称为HyDE（下胚轴确定引擎）的开发，用于测量拟南芥野生型和突变苗的时间分辨图像堆栈的下胚轴长度。我们发现拟南芥在荫蔽刺激下生长迅速，仅在荫蔽下暴露45分钟后就有可测量的生长。与其他芥菜品种相似，这种生长反应发生在多个不同的阶段，包括两个快速生长阶段和一个生长较慢的阶段。利用受遮荫影响的突变体，我们证明了大多数这种早期生长需要通过吲哚-3-丙酮酸途径合成新的生长素。当这一途径的活性降低时，延长生长的第一阶段就会缺失，这与生长素调节基因的活性降低有关。最后，我们发现不同的遮荫强度和持续时间会影响生长响应的形状和大小，这表明遮荫对伸长响应的动态谱。
Plants adapted to environments where light is abundant are especially sensitive to competition for light from neighboring vegetation. As a result, these plants initiate a series of changes known as the shade avoidance syndrome, during which plants elongate their stems and petioles at the expense of leaf development. While the developmental outcomes of exposure to prolonged shade are known, the signaling dynamics during the initial exposure of seedlings to shade is less well studied. Here, we report the development of a new software-based tool, called HyDE (Hypocotyl Determining Engine) to measure hypocotyl lengths of time-resolved image stacks of Arabidopsis wild-type and mutant seedlings. We show that Arabidopsis grows rapidly in response to the shade stimulus, with measurable growth after just 45 minutes of shade exposure. Similar to other mustard species, this growth response occurs in multiple distinct phases, including two phases of rapid growth and one phase with slower growth. Using mutants affected in shade avoidance, we demonstrate that most of this early growth requires new auxin biosynthesis via the indole-3-pyruvate pathway. When activity of this pathway is reduced, the first phase of elongation growth is missing and this is correlated with reduced activity of auxin-regulated genes. Finally, we show that varying shade intensity and duration can affect the shape and magnitude of the growth response, indicating a dynamic spectrum of elongation response to shade.