Heterochrony underpins natural variation in Cardamine hirsuta leaf form
Heterochrony underpins natural variation in Cardamine hirsuta leaf form
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DOI：
10.1073/pnas.1419791112
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发表时间：
2015-08-18
影响因子：
11.1
通讯作者：
Tsiantis, Miltos
中科院分区：
文献类型：
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作者：
Cartolano, Maria;Pieper, Bjorn;Tsiantis, Miltos
生物学中的一个关键问题是物种之间和物种内部的形态变化是否存在相同的过程。在这里，以植物叶片为例，我们表明这两个进化尺度上的多样性原因可能是不同的。一些物种，如拟南芥，只有简单的叶子，而另一些物种，如拟南芥的近亲小豆豆，则有包含小叶的复杂叶子。先前的研究表明，这些种间差异主要是由局部组织生长和模式的变化引起的。现在，通过克隆和表征毛草叶片形状的数量性状位点（QTL），我们发现一个不同的过程，即叶片形状的年龄依赖进程，是该性状在物种内变化的基础。这种QTL效应是由花抑制因子ChFLC的顺式调控变异引起的，因此具有低表达ChFLC等位基因的基因型既能提前开花，又能加速叶形的年龄依赖性变化，包括更快的小叶生成。我们提供的证据表明，这一机制协调了叶片发育与生殖时间，可能有助于优化资源分配给下一代。
A key problem in biology is whether the same processes underlie morphological variation between and within species. Here, by using plant leaves as an example, we show that the causes of diversity at these two evolutionary scales can be divergent. Some species like the model plant Arabidopsis thaliana have simple leaves, whereas others like the A. thaliana relative Cardamine hirsuta bear complex leaves comprising leaflets. Previous work has shown that these interspecific differences result mostly from variation in local tissue growth and patterning. Now, by cloning and characterizing a quantitative trait locus (QTL) for C. hirsuta leaf shape, we find that a different process, age-dependent progression of leaf form, underlies variation in this trait within species. This QTL effect is caused by cis-regulatory variation in the floral repressor ChFLC, such that genotypes with low-expressing ChFLC alleles show both early flowering and accelerated age-dependent changes in leaf form, including faster leaflet production. We provide evidence that this mechanism coordinates leaf development with reproductive timing and may help to optimize resource allocation to the next generation.