Sedentary chromosomal integrons as biobanks of bacterial antiphage defense systems

Science

Baptiste Darracq, Eloi Littner, Manon Brunie, Julia Bos, Pierre Alexandre Kaminski, Florence Depardieu, Weronika Slesak, Kevin Debatisse, Marie Touchon, Aude Bernheim, David Bikard, Frédérique Le Roux, Didier Mazel, Eduardo P. C. Rocha, and Céline Loot 

Summary

Integrons are genetic elements that enable bacteria to rapidly adapt by acquiring and expressing gene cassettes, playing a crucial role in the emergence and spread of antibiotic resistance. Darracq et al. found that integrons that are located in bacterial chromosomes also act as biobanks for antiphage defense cassettes, often streamlined to fit size constraints, highlighting their adaptive importance in bacterial evolution. Mobile integrons, which reside in plasmids, efficiently capture and express genes as needed, minimizing cost. These integrons are known for spreading multidrug resistance, and Kieffer et al. found that they also harbor phage defense systems, allowing bacteria to combat phages when necessary. Thus, integrons are pivotal in both antibiotic and phage resistance.

More information at DOI: https://doi.org/10.1126/science.ads0768