Here's another example of the interplay between microbes and phage. The authors call it BREX (for BacteRiophage EXclusion, emphasis mine) and unlike other phage resistance systems, BREX doesn't seem to cleave viral DNA. It doesn't appear to be as consistently conserved as CRISPR, either - its components may primarily be exchanged horizontally (see Fig 6 in the paper) among many bacterial and archaeal genomes.


Goldfarb, T. et al. BREX is a novel phage resistance system widespread in microbial genomes. EMBO J. e201489455 (2014). doi:10.15252/embj.201489455