Toggle Main Menu Toggle Search

Open Access padlockePrints

The novel anti-phage system Shield co-opts an RmuC domain to mediate phage defense across Pseudomonas species.

Lookup NU author(s): Elliot Macdonald, Dr James ConnollyORCiD, Dr Henrik Strahl von SchultenORCiD, Dr Giusy MarianoORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


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 the Pseudomonas 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 DNA in 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 player within the Pseudomonas bacterial immunity arsenal that displays a novel mechanism of protection, and reveals a role for RmuC domains in phage defense.

Publication metadata

Author(s): Macdonald E, Wright R, Connolly JPR, Strahl H, Brockhurst M, van Houte S, Blower TR, Palmer T, Mariano G

Publication type: Article

Publication status: Published

Journal: PLOS Genetics

Year: 2023

Volume: 19

Issue: 6

Pages: e1010784

Online publication date: 05/06/2023

Acceptance date: 12/05/2023

Date deposited: 04/06/2023

ISSN (electronic): 1553-7404

Publisher: Public Library of Science


DOI: 10.1371/journal.pgen.1010784


Altmetrics provided by Altmetric


Funder referenceFunder name
218622/Z/19/ZWellcome Trust