Deep-sea hydrothermal vents harbour diverse and abundant animals and their symbiotic microorganisms, which together comprise holobionts. The interplay between bacterial members of holobionts and their viruses (phages) is important for maintaining these symbiotic systems; however, phage–bacterium interactions in deep-sea vent holobionts are not well understood. Marine sponges serve as good models for such studies and are used to unveil phage–bacterium interplay via metagenomic analysis. In three demosponges from deep-sea hydrothermal vent fields in the southern Okinawa Trough, the genomes of a diverse array of symbiotic bacteria, including 10 bacterial phyla, were found to lack intact prophages. Genes related to diverse anti-viral defence systems, for example, the restriction–modification and toxin–antitoxin systems, were abundant in the bacterial communities. We also detected phage genes that could complement or compensate host bacterial metabolism, indicating beneficial roles of phage infection. Our findings provide insight into phage–bacterium interplay in sponges from deep-sea hydrothermal vents.

中文翻译：

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冲绳海槽南部热液喷口海绵全生物中独特的噬菌体-细菌相互作用

深海热液喷口蕴藏着多样而丰富的动物及其共生微生物，它们共同组成了全生物。holobionts 的细菌成员与其病毒（噬菌体）之间的相互作用对于维持这些共生系统很重要；然而，深海喷口全生物中的噬菌体-细菌相互作用尚不清楚。海洋海绵可作为此类研究的良好模型，并用于通过宏基因组分析揭示噬菌体-细菌的相互作用。在冲绳海槽南部深海热液喷口场的三个演示海绵中，发现包括 10 个细菌门在内的多种共生细菌的基因组缺乏完整的前噬菌体。与多种抗病毒防御系统相关的基因，例如限制性修饰和毒素-抗毒素系统，在细菌群落中含量丰富。我们还检测到可以补充或补偿宿主细菌代谢的噬菌体基因，表明噬菌体感染的有益作用。我们的研究结果提供了对深海热液喷口海绵中噬菌体-细菌相互作用的深入了解。