Homologous recombination and retention of a single form of most genes shape the highly chimeric mitochondrial genome of a cybrid plant.
Homologous recombination and retention of a single form of most genes shape the highly chimeric mitochondrial genome of a cybrid plant.
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DOI：
10.1111/nph.13188
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发表时间：
2015-04
期刊：
影响因子：
--
通讯作者：
Palmer JD
中科院分区：
文献类型：
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作者：
Sanchez-Puerta MV;Zubko MK;Palmer JD
·被子植物线粒体基因组的结构和进化是由极高的重组和重排速度驱动的。苏铁类植物为研究这些事件提供了一个很好的实验系统，在这个系统中，亲代线粒体通常会融合，它们的基因组会进行重组。人们对这些植物线粒体重组的程度、性质和后果知之甚少。·我们进行了第一项研究，对烟草和黑夜蛾之间的一种囊线虫的细胞器基因组进行了测序，并将其与双亲的基因组进行了比较。·这个线虫基因组是高度重组的，反映了其亲代基因组之间的至少30个交叉和5个基因转换。它也令人惊讶地大(比亲本基因组大41%和%)，但包含90%线粒体基因的单等位基因。·重组产生了一个显著嵌合的线粒体基因组，并完全通过涉及双链断裂修复和/或断裂诱导的复制途径的同源机制发生。保留单一形式的大多数基因可能有利于最小化细胞内的不亲和性和/或反映优先消除重复区域的中性作用力。我们讨论了这些发现与被子植物线粒体DNA中令人惊讶地频繁发生的水平基因和基因组转移的相关性。
• The structure and evolution of angiosperm mitochondrial genomes are driven by extremely high rates of recombination and rearrangement. An excellent experimental system for studying these events is offered by cybrid plants, in which parental mitochondria usually fuse and their genomes recombine. Little is known about the extent, nature, and consequences of mitochondrial recombination in these plants. • We conducted the first study in which the organellar genomes of a cybrid – between Nicotiana tabacum and Hyoscyamus niger – were sequenced and compared to those of its parents. • This cybrid mitochondrial genome is highly recombinant, reflecting at least 30 crossovers and five gene conversions between its parental genomes. It is also surprisingly large (41 and 64% larger than the parental genomes), yet contains single alleles for 90% of mitochondrial genes. • Recombination produced a remarkably chimeric cybrid mitochondrial genome and occurred entirely via homologous mechanisms involving the double-strand break repair and/or break-induced replication pathways. Retention of a single form of most genes could be advantageous to minimize intracellular incompatibilities and/or reflect neutral forces that preferentially eliminate duplicated regions. We discuss the relevance of these findings to the surprisingly frequent occurrence of horizontal gene – and genome – transfer in angiosperm mitochondrial DNAs.