Mechanisms of leaf tooth formation in Arabidopsis
Mechanisms of leaf tooth formation in Arabidopsis
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DOI：
10.1111/j.1365-313x.2010.04156.x
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发表时间：
2010-05-01
期刊：
影响因子：
7.2
通讯作者：
Tsukaya, Hirokazu
中科院分区：
文献类型：
--
作者：
Kawamura, Eiko;Horiguchi, Gorou;Tsukaya, Hirokazu
沿着叶缘的锯齿显示种特异性。虽然复叶的发育研究得很好，但锯齿形成的过程在很大程度上是未知的。为了了解锯齿发育的机制，我们研究了单叶植物拟南芥中可能引起牙齿突出的细胞的独特特征。在牙齿出现后，除了窦和尖端的细胞外，边缘细胞开始迅速伸长。局部细胞分裂似乎使窦部的细胞变小，而不是阻止细胞伸长。随着叶片的成熟，牙齿之间的边缘细胞数量在任何给定的牙齿变得相似。这些结果表明，牙齿是通过重复一种未知的机制形成的，这种机制在空间上监测细胞数量并调节细胞分裂。然后，我们研究了杯形子叶2（CUC 2）在锯齿发育中的作用。cuc 2 -3在叶缘形成较少的根和生长素最大值，通过DR 5 rev：：GFP可见，表明CUC 2通过生长素的调节形成锯齿状图案。与先前的解释相反，叶片轮廓的比较显示，CUC 2促进牙齿的生长，而不是抑制鼻窦的生长。我们发现，突变体与CUC 2表达增加形成异位组织和错误表达SHOOT MERISTEMLESS（STM）之间的窦增强牙齿。在野生型中发现了类似但不频繁的STM表达，表明STM参与单叶的锯齿。我们的研究提供了深入了解叶发育和牙齿形成的形态和分子机制，并强调锯齿和复叶发育之间的相似性。
P>Serration found along leaf margins shows species-specific characters. Whereas compound leaf development is well studied, the process of serration formation is largely unknown. To understand mechanisms of serration development, we investigated distinctive features of cells that could give rise to tooth protrusion in the simple-leaf plant Arabidopsis. After the emergence of a tooth, marginal cells, except for cells at the sinuses and tips, started to elongate rapidly. Localized cell division seemed to keep cells at the sinus smaller, rather than halt cell elongation. As leaves matured, the marginal cell number between teeth became similar in any given tooth. These results suggest that teeth are formed by repetition of an unknown mechanism that spatially monitors cell number and regulates cell division. We then examined the role of CUP-SHAPED COTYLEDON 2 (CUC2) in serration development. cuc2-3 forms fewer hydathodes and auxin maxima, visualized by DR5rev::GFP, at the leaf margin, suggesting that CUC2 patterns serration through the regulation of auxin. In contrast to a previous interpretation, comparison of leaf outlines revealed that CUC2 promotes outgrowth of teeth rather than suppression of growth at the sinuses. We found that mutants with increased CUC2 expression form ectopic tissues and mis-express SHOOT MERISTEMLESS (STM) at the sinus between the enhanced teeth. Similar but infrequent STM expression was found in the wild type, indicating STM involvement in the serration of simple leaves. Our study provides insights into the morphological and molecular mechanisms for leaf development and tooth formation, and highlights similarities between serration and compound leaf development.