Adsorption sequencing (AdsorpSeq) as a rapid method to link environmental bacteriophages to hosts

Through metagenomics, bacteriophage communities across the biosphere are being characterised in great detail. It remains an ongoing challenge to computationally predict phage hosts. Meanwhile, experimental determination of phage-host interactions is currently slow and challenging. To circumvent this challenge, we developed adsorption sequencing (AdsorpSeq), a novel and readily implementable method to measure the key initial step in the infection cycle, the adsorption of phages to host cell surface. In AdsorpSeq, a phage mixture is added to bacterial cell envelope suspensions. Phages that are bound to the cell envelope suspensions are separated from unbound phages through agarose gel electrophoresis, after which isolated DNA from slowly migrating phages is sequenced. Here, we present a proof of concept for AdsorpSeq and show that the technique allows for the separation of model phages based on receptor-adsorbing capabilities. With AdsorpSeq, we identified 26 novel interactions between bacteriophages in a hospital wastewater virome and nine taxonomically distinct bacteria. Characterisation of the phages involved in these novel interactions uncovered, amongst others, a novel biodiversity of jumbo phages. We conclude that AdsorpSeq is an effective new tool to rapidly characterise the adsorption of environmental phages to host cell envelope suspensions.