Extreme genome reduction in Buchnera spp.:: Toward the minimal genome needed for symbiotic life
Extreme genome reduction in Buchnera spp.:: Toward the minimal genome needed for symbiotic life
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DOI：
10.1073/pnas.062067299
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发表时间：
2002-04-02
影响因子：
11.1
通讯作者：
Moya, A
中科院分区：
文献类型：
--
作者：
Gil, R;Sabater-Muñoz, B;Moya, A
Buchnera 是蚜虫的一种互利的细胞内共生体。它们的联系始于大约 2 亿年前，从那时起，宿主和共生体谱系就并行进化。在这个共同进化过程中，布赫内拉经历了基因组大小的急剧减小，只保留了其特殊生活方式所必需的基因。先前的研究报告称，Buchnera spp 的基因组大小。非常一致，表明基因组收缩发生在进化早期，并且现代谱系保留了共同祖先的基因组大小。我们对从五个蚜虫谱系获得的 Buchnera 基因组的物理图谱表明，它们之间的基因组大小并不保守，但在某些物种中已减少到 450 kb。在这里，我们展示了 6 个物种的证据，其基因组大小小于生殖支原体，这是迄今为止报道的最小细菌基因组 (580 kb)。我们的研究结果强烈表明，布赫内拉基因组仍在经历一个还原过程，朝着共生生活方式所需的最低限度基因组发展。
Buchnera is a mutualistic intracellular symbiont of aphids. Their association began about 200 million years ago, with host and symbiont lineages evolving in parallel since that time. During this coevolutionary process, Buchnera has experienced a dramatic decrease of genome size, retaining only essential genes for its specialized lifestyle. Previous studies reported that genome size in Buchnera spp. is very uniform, suggesting that genome shrinkage occurred early in evolution, and that modern lineages retain the genome size of a common ancestor. Our physical mapping of Buchnera genomes obtained from five aphid lineages shows that the genome size is not conserved among them, but has been reduced down to 450 kb in some species. Here we show evidence of six species with a genome size smaller than Mycoplasma genitalium, the smallest bacterial genome reported thus far (580 kb). Our findings strongly suggest that the Buchnera genome is still experiencing a reductive process toward a minimum set of genes necessary for its symbiotic lifestyle.