CRISPR-Cas immune systems are widespread in bacteria and archaea, but not ubiquitous.
Previous work has demonstrated that CRISPR immunity is associated with an infection-
induced fitness cost, which may help explain the patchy distribution observed. However, the
mechanistic basis of this cost has remained unclear. Using Pseudomonas aeruginosa PA14
and its phage DMS3vir as a model, we perform a 30-day evolution experiment under phage
mediated selection. We demonstrate that although CRISPR is initially selected for, bacteria …

The article “Phage gene expression and host responses lead to infection-dependent costs of
CRISPR immunity,” written by Sean Meaden, Loris Capria, Ellinor Alseth, Sylvain Gandon,
Ambarish Biswas, Luca Lenzi, Stineke van Houte, and Edze R. Westra, was originally
published online on 3rd October 2020 without open access. With the author (s), decision to
opt for Open Choice, the copyright of the article changed on 30th October 2020 to© The
Author (s) 2020 and the article is forthwith distributed under a Creative Commons Attribution …