Transposable elements drive rapid phenotypic variation in Capsella rubella
Transposable elements drive rapid phenotypic variation in Capsella rubella
复制标题
转座因子驱动风荠菜的快速表型变异
DOI：
10.1073/pnas.1811498116
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发表时间：
2019-04-02
影响因子：
11.1
通讯作者：
Guo, Ya-Long
中科院分区：
文献类型：
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作者：
Niu, Xiao-Min;Xu, Yong-Chao;Guo, Ya-Long
具有适应意义的性状的快速表型变化对于生物体在不断变化的环境中茁壮成长至关重要。尽管经历遗传瓶颈的物种的遗传变异有限，但这种表型变异是如何迅速实现的尚不清楚。风信子是十字花科一年生近亲交配植物，是研究这一基本问题的一个很好的系统。它的分布比同属物种的分布更广，尽管极端的遗传瓶颈事件严重减少了它的遗传变异。在这里，我们证明了转座元件(TES)是遗传变异的一个重要来源，可以解释其高度的表型多样性。与其异交姐妹种Capsella Grand diflora相比，风疹螺旋体中的TES高度丰富，且4.2%的TES多态与其相邻基因表达水平的变化有关。此外，我们还发现，风疹杆菌自然种群中开花基因C(FLC)上频繁的TE插入可以解释12.5%的开花时间自然变异，这是与适应和适应相关的关键生活史性状。特别是，我们发现最近在FLC的3‘非编码区插入的TE影响了mRNA的稳定性，导致其稳定表达水平降低，从而促进了开花的开始。我们的结果强调，TE插入可以驱动快速的表型变异，这可能有助于在遗传变异有限的物种中适应不断变化的环境。
Rapid phenotypic changes in traits of adaptive significance are crucial for organisms to thrive in changing environments. How such phenotypic variation is achieved rapidly, despite limited genetic variation in species that experience a genetic bottleneck is unknown. Capsella rubella, an annual and inbreeding forb (Brassicaceae), is a great system for studying this basic question. Its distribution is wider than those of its congeneric species, despite an extreme genetic bottleneck event that severely diminished its genetic variation. Here, we demonstrate that transposable elements (TEs) are an important source of genetic variation that could account for its high phenotypic diversity. TEs are (i) highly enriched in C. rubella compared with its outcrossing sister species Capsella grandiflora, and (ii) 4.2% of polymorphic TEs in C. rubella are associated with variation in the expression levels of their adjacent genes. Furthermore, we show that frequent TE insertions at FLOWERING LOCUS C (FLC) in natural populations of C. rubella could explain 12.5% of the natural variation in flowering time, a key life history trait correlated with fitness and adaptation. In particular, we show that a recent TE insertion at the 3' UTR of FLC affects mRNA stability, which results in reducing its steady-state expression levels, to promote the onset of flowering. Our results highlight that TE insertions can drive rapid phenotypic variation, which could potentially help with adaptation to changing environments in a species with limited standing genetic variation.