Cytonuclear Evolution of Rubisco in Four Allopolyploid Lineages
Cytonuclear Evolution of Rubisco in Four Allopolyploid Lineages
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DOI：
10.1093/molbev/msu207
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发表时间：
2014-10-01
影响因子：
10.7
通讯作者：
Wendel, Jonathan F.
中科院分区：
文献类型：
--
作者：
Gong, Lei;Olson, Mischa;Wendel, Jonathan F.
植物中的异源多倍化需要两个不同的核基因组的合并，通常只有一组（通常是母本）亲本质体和线粒体基因组，并具有改变的细胞核化学计量。因此，我们可以预期细胞核的协同进化是异源多倍体进化的一个重要方面。在这里，我们研究了关键叶绿体蛋白rubisco（1，5-二磷酸核酮糖羧化酶/加氧酶）的细胞核协调，该蛋白由核编码的小亚基（SSU）和质体编码的大亚基组成。通过研究基因的组成和多样性以及基因表达在四个模型异源多倍体谱系，拟南芥，花生，芸苔属，烟草，我们表明，旁系同源核编码的rbcS基因二倍体内受到同质化通过基因转换和这种协同进化通过基因转换的特点重复基因（同源）在多倍体水平。多倍体中的许多基因转换是相对于二倍体祖基因组的基因组间转换，发生在同源异型SSU的功能结构域中，并且是定向偏向的，使得母体氨基酸状态是有利的。这种一致的优先母系到父系的基因转换反映在转录水平上，具有母系样rbcS同源物的均匀转录偏好。这些数据，重复在多个不同的被子植物属的一个重要的光合酶，表明细胞核的协同进化可能介导的基因组间的基因转换和改变转录的重复，现在homoeopathic核基因。
Allopolyploidization in plants entails the merger of two divergent nuclear genomes, typically with only one set (usually maternal) of parental plastidial and mitochondrial genomes and with an altered cytonuclear stoichiometry. Thus, we might expect cytonuclear coevolution to be an important dimension of allopolyploid evolution. Here, we investigate cytonuclear coordination for the key chloroplast protein rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase), which is composed of nuclear-encoded, small subunits (SSUs) and plastid-encoded, large subunits. By studying gene composition and diversity as well as gene expression in four model allopolyploid lineages, Arabidopsis, Arachis, Brassica, and Nicotiana, we demonstrate that paralogous nuclear-encoded rbcS genes within diploids are subject to homogenization via gene conversion and that such concerted evolution via gene conversion characterizes duplicated genes (homoeologs) at the polyploid level. Many gene conversions in the polyploids are intergenomic with respect to the diploid progenitor genomes, occur in functional domains of the homoeologous SSUs, and are directionally biased, such that the maternal amino acid states are favored. This consistent preferential maternal-to-paternal gene conversion is mirrored at the transcriptional level, with a uniform transcriptional bias of the maternal-like rbcS homoeologs. These data, repeated among multiple diverse angiosperm genera for an important photosynthetic enzyme, suggest that cytonuclear coevolution may be mediated by intergenomic gene conversion and altered transcription of duplicated, now homoeologous nuclear genes.