Genetically similar temperate phages form coalitions with their shared host that lead to niche-specific fitness effects
Genetically similar temperate phages form coalitions with their shared host that lead to niche-specific fitness effects
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DOI：
10.1038/s41396-020-0637-z
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发表时间：
2020-04-02
期刊：
影响因子：
11
通讯作者：
Buchan, Alison
中科院分区：
文献类型：
--
作者：
Basso, Jonelle T. R.;Ankrah, Nana Y. D.;Buchan, Alison
温带噬菌体与宿主进行长期联系，可能导致互利的相互作用，其全部程度目前尚不清楚。在这里，我们描述了一个具有单一宿主的环境相关模型系统，一种海洋细菌的玫瑰杆菌分支，两个遗传相似的噬菌体（-A和-D）。-D溶原菌株（CB-D）与-A颗粒的重复感染导致了裂解感染，原噬菌体诱导和宿主群体亚群的转化，从而分离出新的-A溶原菌株（CB-A）。表型差异是由不同的溶原-裂解开关机制导致的，在这些溶原之间是明显的，其中CB-A表现出更高的自发诱导发生率。CB-D和CB-A在液体培养中的倍增时间分别为75 min和100 min。当细胞培养进入固定期时，CB-A活菌数为CB-D的一半。与先前的细胞裂解促进生物膜形成的证据一致，CB-A产生的生物膜生物量是CB-D的两倍。由于菌株易受相反噬菌体类型的感染，因此进行共培养竞争以测试适合度效果。当浮游生长时，CB-A的竞争优势是CB-D的三倍。然而，在生物膜生长过程中，CB-D的竞争优势是CB-A的三倍。这些结果表明，基因相似的噬菌体可能由于噬菌体介导的化感作用的复杂形式，在不同的环境生态位中对其共同宿主的竞争力产生不同的影响。这些发现对增强对所有生态系统中普遍存在的宿主-噬菌体相互作用的生态进化动力学的理解具有重要意义。
Temperate phages engage in long-term associations with their hosts that may lead to mutually beneficial interactions, of which the full extent is presently unknown. Here, we describe an environmentally relevant model system with a single host, a species of the Roseobacter clade of marine bacteria, and two genetically similar phages (-A and -D). Superinfection of a -D lysogenized strain (CB-D) with -A particles resulted in a lytic infection, prophage induction, and conversion of a subset of the host population, leading to isolation of a newly -A lysogenized strain (CB-A). Phenotypic differences, predicted to result from divergent lysogenic-lytic switch mechanisms, are evident between these lysogens, with CB-A displaying a higher incidence of spontaneous induction. Doubling times of CB-D and CB-A in liquid culture are 75 and 100 min, respectively. As cell cultures enter stationary phase, CB-A viable counts are half of CB-D. Consistent with prior evidence that cell lysis enhances biofilm formation, CB-A produces twice as much biofilm biomass as CB-D. As strains are susceptible to infection by the opposing phage type, co-culture competitions were performed to test fitness effects. When grown planktonically, CB-A outcompeted CB-D three to one. Yet, during biofilm growth, CB-D outcompeted CB-A three to one. These results suggest that genetically similar phages can have divergent influence on the competitiveness of their shared hosts in distinct environmental niches, possibly due to a complex form of phage-mediated allelopathy. These findings have implications for enhanced understanding of the eco-evolutionary dynamics of host-phage interactions that are pervasive in all ecosystems.