high-quality_bacterial_bins

The temporal dynamics of phage-host interactions in full-scale wastewater treatment plants (WWTP) remain poorly understood. Here, we investigated viral and bacterial dynamics over a nine-year period in an activated sludge WWTP employing bleach addition for sludge foaming control. Metagenomic analysis of 98 time-series samples yielded 3,486 high-quality bacterial bins and 2,435 complete or near-complete viral genomes, grouped into 361 bacterial and 889 viral clusters, respectively. Through CRISPR analysis, we identified 45 virus-host pairs (VHPs) at the bacterial species level. Our findings revealed that the primary bleaching event significantly altered both host and viral dynamics, as well as virus-host relationships as evidenced by changes in virus-to-host ratios. The viral community exhibited similar shifts to the bacterial community following bleaching, suggesting a strong coupling of phage-host interactions. Linear regression analyses of viral and bacterial abundances unveiled complex phage-host dynamics, with many VHPs exhibiting positive slopes significantly < 1, especially for viruses harboring integrase genes, suggesting the prevalence of Piggyback-the-Winner (PtW)-like temperate dynamics. Notably, we found that bleaching treatment appeared to trigger a shift from lysogeny to lysis for the viruses associated with certain foaming-related bacterial species. Such intrinsic biological interactions may contribute to the sustained control of sludge foaming issues.