DISCOVERY OF NEW BACTERIAL ANTI-PHAGE DEFENSE SYSTEMS - BREX AND DISARM

The perpetual arms eace between bacteria and phages has resulted in the evolution of efficient resistance systems, such as CRISPR and restriction enzymes, that protect bacteria against phage infection. Due to the strong selection pressure exerted by phages, and the rapid evolution of their genome, the defense systems are fast evolving and diverging. We utilized the tendency of bacterial and archaeal defense-related genes to cluster together on prokaryotic genomes to identify two novel defense systems, BREX (Bacteriophage Exclusion) and DISARM (Defense Islands System Associated with Restriction-Modification). We demonstrate that introducing these multi-gene complex defense systems into the genome of the model organism Bacillus subtilis provides protection against attacks by a diverse set of viruses.