Comparative genomics of parasitic silkworm microsporidia reveal an association between genome expansion and host adaptation.
Comparative genomics of parasitic silkworm microsporidia reveal an association between genome expansion and host adaptation.
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寄生蚕微孢子虫的比较基因组学揭示了基因组扩展与宿主适应之间的关联
DOI：
10.1186/1471-2164-14-186
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发表时间：
2013-03-16
期刊：
影响因子：
4.4
通讯作者：
Zhou Z
中科院分区：
文献类型：
--
作者：
Pan G;Xu J;Li T;Xia Q;Liu SL;Zhang G;Li S;Li C;Liu H;Yang L;Liu T;Zhang X;Wu Z;Fan W;Dang X;Xiang H;Tao M;Li Y;Hu J;Li Z;Lin L;Luo J;Geng L;Wang L;Long M;Wan Y;He N;Zhang Z;Lu C;Keeling PJ;Wang J;Xiang Z;Zhou Z
家蚕微孢子虫（MicrosporidianNosemaBombycis）是家蚕微孢子虫病的重要病原之一，它的发生给养蚕业造成了巨大的经济损失。到目前为止，还没有找到有效的治疗微粒子病的方法。与其他已知的微孢子虫相比，N.家蚕可以不寻常地寄生在广泛的宿主中。为了深入了解这种寄生虫的病理能力和宿主范围扩展的潜在遗传机制，进行了比较基因组学方法。本文报道了两种微孢子虫（Nosema parasites，N. bombycis和N. antheraeae（一种非驯养家蚕的专性寄生虫）的基因组序列，并与它们的远亲种，即家蚕N.蜜蜂寄生虫（蜜蜂的寄生虫）。我们的比较基因组学分析表明，N。家蚕基因组的扩增主要是由于以下三种分子机制：1）宿主来源的转座因子的增殖，2）从细菌获得许多水平转移的基因，3）产生大量的基因重复。据我们所知，复制的基因不仅来自小规模事件（例如，串联重复）而且来自大规模事件（例如，片段复制）从未在任何报道的微孢子虫基因组中如此丰富。我们的相对测年分析进一步表明，这些重复事件最近出现在非常短的进化时间。此外，一些涉及细胞毒性代谢途径的重复基因被发现经历正选择，提示重复基因在致病能力的适应性进化中的作用。基因组扩增很少被认为是作用于高度简化和紧凑的寄生微孢子虫基因组的进化结果。这项研究首次表明，寄生虫基因组可以通过几种常见的分子机制（如基因复制、水平基因转移和转座因子扩增）扩展而不是缩小。我们还表明，重复的基因可以作为进化创新的原材料，可能有助于增加致病能力。基于我们的研究，我们提出了N。家蚕应作为微粒子病治疗设计的主要目标。
Microsporidian Nosema bombycis has received much attention because the pébrine disease of domesticated silkworms results in great economic losses in the silkworm industry. So far, no effective treatment could be found for pébrine. Compared to other known Nosema parasites, N. bombycis can unusually parasitize a broad range of hosts. To gain some insights into the underlying genetic mechanism of pathological ability and host range expansion in this parasite, a comparative genomic approach is conducted. The genome of two Nosema parasites, N. bombycis and N. antheraeae (an obligatory parasite to undomesticated silkworms Antheraea pernyi), were sequenced and compared with their distantly related species, N. ceranae (an obligatory parasite to honey bees). Our comparative genomics analysis show that the N. bombycis genome has greatly expanded due to the following three molecular mechanisms: 1) the proliferation of host-derived transposable elements, 2) the acquisition of many horizontally transferred genes from bacteria, and 3) the production of abundnant gene duplications. To our knowledge, duplicated genes derived not only from small-scale events (e.g., tandem duplications) but also from large-scale events (e.g., segmental duplications) have never been seen so abundant in any reported microsporidia genomes. Our relative dating analysis further indicated that these duplication events have arisen recently over very short evolutionary time. Furthermore, several duplicated genes involving in the cytotoxic metabolic pathway were found to undergo positive selection, suggestive of the role of duplicated genes on the adaptive evolution of pathogenic ability. Genome expansion is rarely considered as the evolutionary outcome acting on those highly reduced and compact parasitic microsporidian genomes. This study, for the first time, demonstrates that the parasitic genomes can expand, instead of shrink, through several common molecular mechanisms such as gene duplication, horizontal gene transfer, and transposable element expansion. We also showed that the duplicated genes can serve as raw materials for evolutionary innovations possibly contributing to the increase of pathologenic ability. Based on our research, we propose that duplicated genes of N. bombycis should be treated as primary targets for treatment designs against pébrine.
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影响因子：
5.4
作者：
Archibald JM;Richards TA
通讯作者：
Richards TA
影响因子：
10.7
作者：
Castresana, J
通讯作者：
Castresana, J
影响因子：
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作者：
Gill, Erin E.;Fast, Naomi M.
通讯作者：
Fast, Naomi M.
影响因子：
7
作者：
Li, Ruiqiang;Zhu, Hongmei;Wang, Jun
通讯作者：
Wang, Jun
影响因子：
3.3
作者：
Keeling PJ;Corradi N;Morrison HG;Haag KL;Ebert D;Weiss LM;Akiyoshi DE;Tzipori S
通讯作者：
Tzipori S