TY - JOUR T1 - Viral coinfection is shaped by bacterial ecology and virus-virus interactions across diverse microbial taxa and environments JF - bioRxiv DO - 10.1101/038877 SP - 038877 AU - Samuel L. Díaz-Muñoz Y1 - 2016/01/01 UR - http://biorxiv.org/content/early/2016/02/07/038877.abstract N2 - Viral coinfection is a common across taxa and environments. Coinfection can enable genetic exchange, alter the dynamics of infections, and change the course of viral evolution. Despite the importance of coinfection to viral ecology and evolution, the factors that influence the frequency and extent of viral coinfection remain largely unexplored. Here I employ an extensive data set of virus-host interactions representing 6,564 microbial hosts and 13,103 viruses, to test the importance of bacterial traits and virus-virus interactions in shaping coinfection dynamics across a wide variety of taxa and environments. Using data from phage-host infection matrices, I found that bacterial ecology was the most important factor explaining variation (>28%) in the potential for coinfection. Realized (actual) coinfection was affected by bacterial defense mechanisms at the single-cell level. In a natural environment, the presence of CRISPR spacers in marine bacteria limited coinfections with active viruses by ∽50%, despite the absence of spacer matches in any active infection. Analysis of viral infections mined from published bacterial and archaeal sequence data (n= 5,492 hosts), showed prophages limited coinfection of host cultures by other prophages, but not extrachromosomal viruses. At the single-cell level, prophages virtually eliminated coinfection. Virus-virus interactions also enhanced coinfection with culture coinfection by ssDNA and dsDNA viruses twice as likely to occur than ssDNA-only coinfections. Collectively, these results suggest bacterial ecology and virus-virus interactions are strong drivers of coinfection across different taxa and environments. These findings highlight that virus-virus interactions constitute an important selective pressure on viruses that is often underappreciated. ER -