Multi-layered genome defences in bacteria
Aleksei Agapov, Kate S. Baker, Paritosh Bedekar, Rama P. Bhatia, Tim R. Blower, Michael A. Brockhurst, Cooper Brown, Charlotte E. Chong, Joanne L. Fothergill, Shirley Graham, James P. J. Hall, Alice Maestri, Stuart McQuarrie, Anna Olina, Stefano Pagliara, Mario Recker, Anna Richmond, Steven J. Shaw, Mark D. Szczelkun, Tiffany Taylor, Stineke van Houte, Sam C Went, Edze R. Westra, Malcolm F. White, Rosanna Wright
Abstract
Bacteria have evolved a variety of defence mechanisms to protect against mobile genetic elements, including restriction-modification systems and CRISPR-Cas. In recent years, dozens of previously unknown defence systems (DSs) have been discovered. Notably, diverse DSs often coexist within the same genome, and some co-occur at frequencies significantly higher than would be expected by chance, implying potential synergistic interactions. Recent studies have provided evidence of defence mechanisms that enhance or complement one another. Here, we review the interactions between DSs at the mechanistic, regulatory, ecological and evolutionary levels.