Deep-sea bacteriophages facilitate host utilization of polysaccharides

Bacteriophages are ubiquitous in nature and play key roles in various ecosystems. They impact microbial community composition and reprogram the metabolism of diverse host cells using auxiliary metabolic genes (AMGs). Whether bacteriophages can reprogram host polysaccharide metabolism through AMGs remains unclear, however. Here, we found for the first time that polysaccharides induce the production of different types of bacteriophages in two deep-sea Lentisphaerae strains (WC36 and zth2). Through physiological assays, genomic analysis and transcriptomics assays, we found that these bacteriophages might assist their hosts in metabolizing polysaccharides through AMGs. Moreover, the isolated bacteriophages could effectively assist a marine bacterium ( Pseudomonas stutzeri 273) in metabolizing and utilizing polysaccharide to promote its growth. These findings shed light on the importance of atypical and poorly understood virus-host interactions and bring us closer to understanding the potential role of deep-sea viruses in marine ecosystems.