Reductions in complexity of mitochondrial genomes in lichen-forming fungi shed light on genome architecture of obligate symbioses
Reductions in complexity of mitochondrial genomes in lichen-forming fungi shed light on genome architecture of obligate symbioses
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DOI：
10.1111/mec.14519
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发表时间：
2018-03-01
影响因子：
4.9
通讯作者：
Tripp，Erin A.
中科院分区：
文献类型：
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作者：
Pogoda，Cloe S.;Keepers，Kyle G.;Tripp，Erin A.
共同进化类群之间的共生通常以基因组减少为标志，例如至少一个伙伴中蛋白质编码基因的丢失，作为减少冗余或基因组间冲突的一种手段。为了探索一组标志性但尚未充分研究的专性共生生物中的这一现象，我们将 22 个新测序和注释的地衣真菌物种的线粒体基因组与 167 个非地衣真菌的线粒体基因组进行了比较。我们的结果证明了地衣真菌线粒体中 atp9 的首次大规模丢失。尽管 atp9 在线粒体能量产生中具有关键功能，但我们发现 atp9 在 22 个研究物种中的 10 个物种的 3 个不同谱系中独立丢失。在每个地衣所涉及的其他共生体基因组中搜索预测的 atp9 功能副本，揭示了所有 10 个实例中光合藻类伴侣或其他共生真菌中 atp9 的全长、推测功能副本。总之，这些数据提供了必然共生关系的证据，其中核心基因组过程已被简化，这可能是由于共同进化。
Symbioses among co‐evolving taxa are often marked by genome reductions such as a loss of protein‐coding genes in at least one of the partners as a means of reducing redundancy or intergenomic conflict. To explore this phenomenon in an iconic yet under‐studied group of obligate symbiotic organisms, mitochondrial genomes of 22 newly sequenced and annotated species of lichenized fungi were compared to 167 mitochondrial genomes of nonlichenized fungi. Our results demonstrate the first broad‐scale loss ofatp9from mitochondria of lichenized fungi. Despite key functions in mitochondrial energy production, we show thatatp9has been independently lost in three different lineages spanning 10 of the 22 studied species. A search for predicted, functional copies ofatp9among genomes of other symbionts involved in each lichen revealed the full‐length, presumably functional copies ofatp9in either the photosynthetic algal partner or in other symbiotic fungi in all 10 instances. Together, these data yield evidence of an obligate symbiotic relationship in which core genomic processes have been streamlined, likely due to co‐evolution.