Bacteriophages encoding anti-CRISPR proteins (Acrs) must cooperate to overcome phage resistance mediated by the bacterial immune system CRISPR-Cas, where the first phage blocks CRISPR-Cas immunity in order to allow a second Acr phage to successfully replicate. However, in nature, bacteria are frequently not pre-immunized, and phage populations are often not clonal, exhibiting variations in Acr presence and strength. We explored how interactions between Acr phages and initially sensitive bacteria evolve, both in the presence and absence of competing phages lacking Acrs. We find that Acr phages benefit "Acr-negative" phages by limiting the evolution of CRISPR-based resistance and helping Acr-negative phages to replicate on resistant host sub-populations. These benefits depend on the strength of CRISPR-Cas inhibitors and result in strong Acrs providing smaller fitness advantages than weaker ones when Acr phages compete with Acr-negative phages. These results indicate that different Acr types shape the evolutionary dynamics and social interactions of phage populations in natural communities.

中文翻译：

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利用抗CRISPR噬菌体的协同行为。

编码抗CRISPR蛋白（Acrs）的噬菌体必须协同克服细菌免疫系统CRISPR-Cas介导的噬菌体抗性，其中第一个噬菌体会阻断CRISPR-Cas免疫，以使第二个Acr噬菌体成功复制。但是，在自然界中，细菌通常不进行预免疫，噬菌体种群通常也不克隆，在Acr的存在和强度方面表现出差异。我们探索了在存在和不存在缺乏Acrs的竞争性噬菌体的情况下，Acr噬菌体与最初的敏感细菌之间的相互作用如何进化。我们发现，Acr噬菌体通过限制基于CRISPR的抗性进化并帮助Acr阴性噬菌体在抗性宿主亚群上复制而使“ Acr阴性”噬菌体受益。这些好处取决于CRISPR-Cas抑制剂的强度，当Acr噬菌体与Acr阴性噬菌体竞争时，强大的Acrs会提供比较弱的Acrs更小的适应性优势。这些结果表明，不同的Acr类型影响着自然社区中噬菌体种群的进化动力学和社会互动。