DISCOVERY OF NEW ANTI-PHAGE DEFENSE SYSTEMS ENCODING GENES WITH NO DOMAIN ANNOTATION

In order to survive phage infections, bacteria have developed multiple lines of defense, including restriction-modification, CRISPR-Cas, and abortive infection systems. Although these systems have been studied intensively, there is evidence that many new anti-phage defense systems remain to be discovered. In a previous study we showed that new defense systems can be discovered based on the tendency of certain gene families (pfams) to be co-localized in genomic defense islands [1]. Here we extend the search also for new defense systems that do not encode defined proteins domain. Our search reveals a new set of phage resistance systems, bringing us closer into realizing the complete “immune-system” of bacteria, and understanding the various factors that influence the ongoing phage-bacteria arms race.

[1] Doron et al. Systematic discovery of antiphage defense systems in the microbial pangenome. Science, 359(6379), pii: eaar4120 (2018).