Comparative Genome Analysis Reveals Divergent Genome Size Evolution in a Carnivorous Plant Genus
Comparative Genome Analysis Reveals Divergent Genome Size Evolution in a Carnivorous Plant Genus
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DOI：
10.3835/plantgenome2015.04.0021
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发表时间：
2015-11
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通讯作者：
G. H. Vu;Thomas Schmutzer;F. Bull;H. X. Cao;J. Fuchs;Trung D. Tran;G. Jovtchev;K. Pistrick;N. Stein;A. Pečinka;P. Neumann;P. Novák;J. Macas;P. Dear;F. Blattner;U. Scholz;I. Schubert
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作者：
G. H. Vu;Thomas Schmutzer;F. Bull;H. X. Cao;J. Fuchs;Trung D. Tran;G. Jovtchev;K. Pistrick;N. Stein;A. Pečinka;P. Neumann;P. Novák;J. Macas;P. Dear;F. Blattner;U. Scholz;I. Schubert
C值悖论在超过40年后仍未完全解决，开花植物基因组大小的2,350倍变异就是例证。肉食性的Lentibulariaceae Genlisea属，显示出25倍的基因组大小范围，是研究进化基因组大小变化的机制和后果的一个有前途的主题。应用基因组，系统发育和细胞遗传学的方法，我们发现了双向基因组大小的进化属Genlisea。黑刺木基因组（86 Mbp）可能通过逆转录元件沉默和缺失偏置双链断裂（DSB）修复而缩小，从祖先的400 Mbp缩小到800 Mbp，成为显花植物中最小的基因组之一。共和党Hispidula Stapf基因组通过全基因组复制（WGD）和反转录转座扩增至1550 Mbp。毛节藻（Genlisea hispidula）从毛节藻（G. nigroplasticclade 29 Ma.矮毛蕨圣希尔(179 Mbp），是G. nigroplasty，证明是最近的（自体）四倍体。我们的分析表明，一个共同的祖先属Genlisea与一个中间的1C值（400-800 Mbp）和随后的快速基因组大小的进化方向相反。较大基因组的许多丰富的重复序列在较小的基因组中不存在，这使人们对它们对生物体的功能产生了怀疑，而复发性WGD似乎可以防止基因组萎缩时基本元素的丢失。我们无法确定与基因组大小变化相关的栖息地或生活策略的任何一致差异，这增加了这些变化可能是选择性中性的可能性。
The C‐value paradox remains incompletely resolved after >40 yr and is exemplified by 2,350‐fold variation in genome sizes of flowering plants. The carnivorous Lentibulariaceae genus Genlisea, displaying a 25‐fold range of genome sizes, is a promising subject to study mechanisms and consequences of evolutionary genome size variation. Applying genomic, phylogenetic, and cytogenetic approaches, we uncovered bidirectional genome size evolution within the genus Genlisea. The Genlisea nigrocaulis Steyerm. genome (86 Mbp) has probably shrunk by retroelement silencing and deletion‐biased double‐strand break (DSB) repair, from an ancestral size of 400 to 800 Mbp to become one of the smallest among flowering plants. The G. hispidula Stapf genome has expanded by whole‐genome duplication (WGD) and retrotransposition to 1550 Mbp. Genlisea hispidula became allotetraploid after the split from the G. nigrocaulis clade ∼29 Ma. Genlisea pygmaea A. St.‐Hil. (179 Mbp), a close relative of G. nigrocaulis, proved to be a recent (auto)tetraploid. Our analyses suggest a common ancestor of the genus Genlisea with an intermediate 1C value (400–800 Mbp) and subsequent rapid genome size evolution in opposite directions. Many abundant repeats of the larger genome are absent in the smaller, casting doubt on their functionality for the organism, while recurrent WGD seems to safeguard against the loss of essential elements in the face of genome shrinkage. We cannot identify any consistent differences in habitat or life strategy that correlate with genome size changes, raising the possibility that these changes may be selectively neutral.