Skoltech researchers Dmitry Sutormin and Svetlana Dubiley co-authored a novel preprint “An interplay between viruses and bacteria associated with marine sponges from the White Sea revealed by metagenomics” that has been recently released at bioRxiv. The paper is focused on interactions between sponges and their microbiome. To investigate possible interactions within the sponge-associated communities and between them, the researchers probed the microbiomes and viromes of cold-water sympatric sponges Isodictya palmata, Halichondria panicea, and Halichondria sitiens by 16S and shotgun metagenomics. The scientists showed that the bacterial and viral communities associated with these White Sea sponges are species-specific and different from the surrounding water. Interestingly, the abundance of bacterial antiphage defense systems was comparable in the metagenomes of the sponges and the surrounding water, thus distinguishing the White Sea sponges from those inhabiting the tropical seas. The authors developed a network-based approach for the combined analysis of CRISPR-spacers and protospacers. Using this approach, they showed that the virus-host interactions within the sponge-associated community are typically more abundant than the inter-community interactions. Full text of the preprint is available here.