Phage defense mechanism and genome editing using novel retrons sourced from isolated environmental bacteria

Retrons are reverse transcription systems that bacteria use to defend against phage predation. To better understand retron biology and the diversity of retrons in the environment, six novel retrons were isolated from their host bacteria in environmental soil/water samples. We characterized the operons of these retrons and tested their ability to defend against a panel of E. coli phages. For two of these retrons, we further unraveled the mechanism of defense by identifying the phage genes responsible for triggering the system. Finally, we also engineered our novel retrons to serve as tools for gene editing (retron recombineering) and benchmarked their efficiency in editing a site on the E. coli genome.