Metagenome assembled genomes targeting viruses from Southern Ontario sanitary landfill leachate. landfill metagenome

Viruses are the most abundant microbial guild on the planet, impacting microbial community structure and ecosystem services. Viruses are underrepresented in databases and specifically understudied in engineered environments. We examined host-associated viruses from a municipal landfill across two years via CRISPR spacer to viral protospacer mapping. Viruses comprised ~5% of the assembled community DNA sequence. A total of 506 unique virus-host connections capture hypertargeted viral populations and host CRISPR array adaptation over time, as well as viruses predicted to infect across multiple phyla, suggesting that some viruses may be far less host-specific than is currently understood. We detected 190 viral elements that encode CRISPR arrays, including the longest virally-encoded CRISPR array described to date. CRISPR-encoding proviruses integrated into host chromosomes were observed, as examples of CRISPR-immunity-based superinfection exclusion. Our networks highlight virus-host interactions that are rare or have not previously been described, but which influence the ecology of this dynamic engineered system.