Toggle Main Menu Toggle Search

Open Access padlockePrints

A novel variant of the Listeria monocytogenes type VII secretion system EssC component is associated with an Rhs toxin

Lookup NU author(s): Kieran Bowran, Stephen Garrett, Professor Tracy Palmer FRS FRSE FMedSciORCiD



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


© 2023 The Authors.The type VIIb protein secretion system (T7SSb) is found in Bacillota (firmicute) bacteria and has been shown to mediate inter-bacterial competition. EssC is a membrane-bound ATPase that is a critical component of the T7SSb and plays a key role in substrate recognition. Prior analysis of available genome sequences of the foodborne bacterial pathogen Listeria monocy-togenes has shown that although the T7SSb was encoded as part of the core genome, EssC could be found as one of seven different sequence variants. While each sequence variant was associated with a specific suite of candidate substrate proteins encoded immediately downstream of essC, many LXG-domain proteins were encoded across multiple essC sequence variants. Here, we have extended this analysis using a diverse collection of 37 930 L. monocytogenes genomes. We have identified a rare eighth variant of EssC present in ten L. monocytogenes lineage III genomes. These genomes also encode a large toxin of the rearrangement hotspot (Rhs) repeat family adjacent to essC8, along with a probable immunity protein and three small accessory proteins. We have further identified nine novel LXG-domain proteins, and four additional chromosomal hotspots across L. monocytogenes genomes where LXG proteins can be encoded. The eight L. monocytogenes EssC variants were also found in other Listeria species, with additional novel EssC types also identified. Across the genus, species frequently encoded multiple EssC types, indicating that T7SSb diversity is a primary feature of the genus Listeria.

Publication metadata

Author(s): Bowran K, Garrett SR, van Vliet AHM, Palmer T

Publication type: Article

Publication status: Published

Journal: Microbial Genomics

Year: 2023

Volume: 9

Issue: 6

Print publication date: 01/06/2023

Online publication date: 06/06/2023

Acceptance date: 17/04/2023

Date deposited: 06/07/2023

ISSN (electronic): 2057-5858

Publisher: Microbiology Society


DOI: 10.1099/mgen.0.001036

PubMed id: 37278699


Altmetrics provided by Altmetric


Funder referenceFunder name
Biotechnology and Biological Sciences Research Council
Wellcome Trust