Genome-wide Characterization of Diverse Bacteriophages Enabled by RNA-Binding CRISPRi

Bacteriophages constitute one of the largest sources of unknown gene content in the biosphere. Even for well-studied model phages, robust experimental approaches to identify and study their essential genes remain elusive. We uncover and exploit the conserved vulnerability of the phage transcriptome to facilitate genome-wide protein expression knockdown via programmable RNA-binding protein dRfxCas13d (CRISPRi-ART) across diverse phages and their host. Establishing the first broad-spectrum phage functional genomics platform, we predict over 90 essential genes across four phage genomes, a third of which have no known function. These results highlight hidden infection strategies encoded in the most abundant biological entities on earth and provide a facile platform to study them.