High-throughput discovery of phage receptors using transposon insertion sequencing of bacteria

As the most abundant microbes on earth, novel bacteriophage (phage;
bacteria-specific viruses) are readily isolated from environmental
samples. However, it remains challenging to characterize phage-bacteria
interactions, such as the host receptor(s) phage bind to initiate
infection. Here, we tested whether transposon insertion sequencing, INSeq,
could be used to identify bacterial genes involved in phage binding. As
proof of concept, results showed that INSeq screens successfully
identified genes encoding known receptors for previously characterized
viruses of Escherichia coli (phage T6, T2, T4 and T7). INSeq screens were
then used to identify genes involved during infection of six newly
isolated coliphage. Results showed that candidate receptors could be
successfully identified for the majority (five of six) of the phage;
furthermore, genes encoding the phage receptor(s) were the top hit(s) in
the analyses of the successful screens. INSeq screens provide a generally
useful method for high-throughput discovery of phage receptors. We discuss
limitations of our approach when examining uncharacterized phage, as well
as usefulness of the method for exploring the evolution of broad versus
narrow use of cellular receptors among phage in the biosphere.