Shaping of a three-dimensional carnivorous trap through modulation of a planar growth mechanism
Shaping of a three-dimensional carnivorous trap through modulation of a planar growth mechanism
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DOI：
10.1371/journal.pbio.3000427
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发表时间：
2019-10-01
期刊：
影响因子：
9.8
通讯作者：
Coen, Enrico
中科院分区：
文献类型：
--
作者：
Lee, Karen J. I.;Bushell, Claire;Coen, Enrico
树叶的形状多种多样，从简单轮廓的平板到杯状的陷阱。虽然对平面叶片发育机制的了解已经取得了很大进展，但尚不清楚在更复杂的曲形发育过程中，形状变化是由相似的还是独特的机制造成的。在这里，我们使用三维成像和细胞和克隆分析，结合计算模型，分析了肉食性植物吉巴盘藻的杯状陷阱的发展。我们发现，从早期发育阶段的近球形到成熟时腹中线拉直的扁球体的转变可以用生长速度和取向的空间差异来解释。关于时空控制的不同假设预测了细胞形状和大小的不同模式，并通过量化细胞和克隆的各向异性进行了实验验证。我们认为生长方向是由近端极场指定的，类似于解释拟南芥叶片发育的假设，不同的是，在拟南芥中，场通过高度弯曲的组织片传播。通过陷阱内表面上腺毛的取向提供了极性场的独立证据。综上所述，我们的结果表明，复杂的3D叶片形状的形态发生可以用与平面叶片相似的机制来解释，这表明对共同生长框架的简单调制是形成各种形态的基础。
Leaves display a remarkable range of forms, from flat sheets with simple outlines to cup-shaped traps. Although much progress has been made in understanding the mechanisms of planar leaf development, it is unclear whether similar or distinctive mechanisms underlie shape transformations during development of more complex curved forms. Here, we use 3D imaging and cellular and clonal analysis, combined with computational modelling, to analyse the development of cup-shaped traps of the carnivorous plant Utricularia gibba. We show that the transformation from a near-spherical form at early developmental stages to an oblate spheroid with a straightened ventral midline in the mature form can be accounted for by spatial variations in rates and orientations of growth. Different hypotheses regarding spatiotemporal control predict distinct patterns of cell shape and size, which were tested experimentally by quantifying cellular and clonal anisotropy. We propose that orientations of growth are specified by a proximodistal polarity field, similar to that hypothesised to account for Arabidopsis leaf development, except that in Utricularia, the field propagates through a highly curved tissue sheet. Independent evidence for the polarity field is provided by the orientation of glandular hairs on the inner surface of the trap. Taken together, our results show that morphogenesis of complex 3D leaf shapes can be accounted for by similar mechanisms to those for planar leaves, suggesting that simple modulations of a common growth framework underlie the shaping of a diverse range of morphologies.