Multi-host environments select for hostgeneralist conjugative plasmids
Multi-host environments select for hostgeneralist conjugative plasmids
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DOI：
10.1186/s12862-016-0642-z
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发表时间：
2016-04-02
影响因子：
3.4
通讯作者：
Brockhurst, Michael A.
中科院分区：
文献类型：
--
作者：
Kottara, Anastasia;Hall, James P. J.;Brockhurst, Michael A.
背景资料：接合质粒通过在种内和种间转移重要的生态基因在细菌进化中发挥重要作用。种间水平基因转移的一个关键限制是质粒宿主范围。在这里，我们实验测试的影响，单一和多宿主环境的主机范围演变的一个大的接合汞抗性质粒，pQBR 57。具体地，pQBR 57在单一宿主物种（荧光假单胞菌或恶臭假单胞菌）的菌株之间缀合，或在荧光假单胞菌和恶臭假单胞菌之间交替缀合。至关重要的是，细菌宿主不允许演变，使我们能够观察到质粒的进化反应在isolation.Results：在所有治疗质粒演变更高的共轭率随着时间的推移。质粒在适应其宿主细菌物种的单宿主环境中进化，变得更便宜，但在荧光假单胞菌适应质粒的情况下，在恶臭假单胞菌中变得更昂贵，这表明进化的权衡。结论：在单宿主环境中，由于适应度的权衡，宿主专属性质粒在多宿主环境中进化，而在多宿主环境中，这种权衡可以被规避，导致宿主通用质粒的进化。
Background: Conjugative plasmids play an important role in bacterial evolution by transferring ecologically important genes within and between species. A key limit on interspecific horizontal gene transfer is plasmid host range. Here, we experimentally test the effect of single and multi-host environments on the host-range evolution of a large conjugative mercury resistance plasmid, pQBR57. Specifically, pQBR57 was conjugated between strains of a single host species, either P. fluorescens or P. putida, or alternating between P. fluorescens and P. putida. Crucially, the bacterial hosts were not permitted to evolve allowing us to observe plasmid evolutionary responses in isolation.Results: In all treatments plasmids evolved higher conjugation rates over time. Plasmids evolved in single-host environments adapted to their host bacterial species becoming less costly, but in the case of P. fluorescens-adapted plasmids, became costlier in P. putida, suggesting an evolutionary trade-off. When evolved in the multi-host environment plasmids adapted to P. fluorescens without a higher cost in P. putida.Conclusion: Whereas evolution in a single-host environment selected for host-specialist plasmids due to a fitness trade-off, this trade-off could be circumvented in the multi-host environment, leading to the evolution of host-generalist plasmids.