The novel anti-phage system Shield co-opts an RmuC domain to mediate phage defense across < i > Pseudomonas < /i > species

by Elliot Macdonald, Rosanna Wright, James P. R. Connolly, Henrik Strahl, Michael Brockhurst, Stineke van Houte, Tim R. Blower, Tracy Palmer, Giuseppina Mariano

Competitive bacteria-bacteriophage interactions have resulted in the evolution of a plethora of bacterial defense systems preventing phage propagation. In recent years, computational and bioinformatic approaches have underpinned the discovery of numerous novel bacterial defense systems. Anti-phage systems are frequently encoded together in genomic loci termed defense islands. Here we report the identification and characterisation of a novel anti-phage system, that we have termed Shield, which forms part of thePseudomonas defensive arsenal. The Shield system comprises the core component ShdA, a membrane-bound protein harboring an RmuC domain. Heterologous production of ShdA alone is sufficient to mediate bacterial immunity against several phages. We demonstrate that Shield and ShdA confer population-level immunity and that they can also decrease transformation efficiency. We further show that ShdA homologues can degrade DNAin vitro and, when expressed in a heterologous host, can alter the organisation of the host chromosomal DNA. Use of comparative genomic approaches identified how Shield can be divided into four subtypes, three of which contain additional components that in some cases can negatively affect the activity of ShdA and/or provide additional lines of phage defense. Collectively, our results identify a new ...

Source: PLoS Genetics - June 5, 2023 Category: Genetics & Stem Cells Authors: Elliot Macdonald Source Type: research