Biogeography and host interactions of CPR and DPANN viruses in acid mine drainage sediments

The CPR and DPANN superphyla are globally distributed in anoxic habitats including extreme environments. However, the biogeography and potential ecological functions of their viruses remain unexplored. Here, we recover diverse CPR/DPANN metagenomic viral genomes from 90 acid mine drainage (AMD) sediments sampled across southeast China. Our data reveal deterministic processes as the primary driver of virome assembly shaping the distinct distribution patterns of CPR and DPANN viruses. While lifestyle prediction shows higher lytic virus diversity associated with DPANN, both CPR/DPANN viruses likely use the Piggyback-the-winner (PtW) strategy to co-exist with hosts in AMD sediments, with CPR viromes exhibiting increased lysis in low host-density regimes under intensive acidity/salinity conditions. A subsequent metatranscriptomic analysis uncovers diverse functional genes encoded by CPR and DPANN viruses actively expressed in situ, potentially supplementing host metabolisms yet diverging in replication, transcription, and translation-related functions. Furthermore, partial correlation network analysis suggests that putative symbiotic hosts of the CPR/DPANN may confer protection against viral infection through enhanced antiviral defense. Our results highlight the complex interplays between viruses, DPANN and CPR organisms, and their symbiotic hosts.