Novel integrative elements and genomic plasticity in ocean ecosystems
Novel integrative elements and genomic plasticity in ocean ecosystems
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DOI：
10.1016/j.cell.2022.12.006
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发表时间：
2023-01-05
期刊：
影响因子：
64.5
通讯作者：
Chisholm，Sallie W.
中科院分区：
文献类型：
--
作者：
Hackl，Thomas;Laurenceau，Raphael;Chisholm，Sallie W.
水平基因转移加速了微生物的进化。海洋picocyanobacteriumProchlorococcus具有很高的基因组可塑性，但其潜在的机制是难以捉摸的。在这里，我们报告了一个新的DNA转座子家族-“类型转座子”-其中一些是病毒卫星，而另一些携带货物，如营养获取基因，这塑造了这个全球丰富的属的遗传变异性。Tycheposons共享独特的移动生命周期相关的标志基因，包括深分支位点特异性酪氨酸重组酶。它们在tRNA基因上的切除和整合似乎驱动了基因组岛的重塑，基因组岛是细菌中柔性基因的关键储存库。在选择实验中，含有硝酸盐同化盒的类型座子动态地获得和丢失，从而促进染色体重排和宿主适应。从海水中收获的囊泡和噬菌体颗粒富含类型座子，为它们在野外的传播提供了一种手段。在与原绿球藻共生的微生物中发现了类似的元素，这表明在广阔的贫营养海洋中微生物多样化的共同机制。
Horizontal gene transfer accelerates microbial evolution. The marine picocyanobacteriumProchlorococcusexhibits high genomic plasticity, yet the underlying mechanisms are elusive. Here, we report a novel family of DNA transposons—"tycheposons"—some of which are viral satellites while others carry cargo, such as nutrient-acquisition genes, which shape the genetic variability in this globally abundant genus. Tycheposons share distinctive mobile-lifecycle-linked hallmark genes, including a deep-branching site-specific tyrosine recombinase. Their excision and integration at tRNA genes appear to drive the remodeling of genomic islands—key reservoirs for flexible genes in bacteria. In a selection experiment, tycheposons harboring a nitrate assimilation cassette were dynamically gained and lost, thereby promoting chromosomal rearrangements and host adaptation. Vesicles and phage particles harvested from seawater are enriched in tycheposons, providing a means for their dispersal in the wild. Similar elements are found in microbes co-occurring withProchlorococcus, suggesting a common mechanism for microbial diversification in the vast oligotrophic oceans.