Biology subjects

Aparicio-Maldonado, C.

Publications and source records attributed to Aparicio-Maldonado, C..

2 recordsLinked to original sources

bioRxiv2022

Defence systems provide synergistic anti-phage activity in E. coli

Bacterial defence against phage predation involves diverse defence systems acting both individually and concurrently, yet their interactions remain poorly understood. We investigated >100 defence systems in 42,925 bacterial genomes and identified numerous instances of their non-random co-occurrence and mutual exclusion. For several pairs of defence systems significantly co-occurring in Escherichia coli strains, we demonstrate synergistic anti-phage activity, including tmn synergising with defence systems containing sensory switch ATPase domains. Some of the defence system pairs that are mutually exclusive in E. coli significantly co-occur in other taxa, and one tested mutually exclusive pair showed synergy. These findings demonstrate compatibility and synergy between defence systems, allowing bacteria to adopt flexible strategies for phage defence, driven by specific environmental pressures. The evolution of bacterial immune repertoires seems to be shaped largely by selection for resistance to host-specific phages rather than by negative epistasis.

microbiology↗

bioRxiv2021

Class I DISARM provides anti-phage and anti-conjugation activity by unmethylated DNA recognition

Bacteriophages impose a strong evolutionary pressure on microbes for the development of mechanisms of survival. Multiple new mechanisms of innate defense have been described recently, with the molecular mechanism of most of them remaining uncharacterized. Here, we show that a Class 1 DISARM (defense island system associated with restriction-modification) system from Serratia sp. provides broad protection from double-stranded DNA phages, and drives a population of single-stranded phages to extinction. We identify that protection is not abolished by deletion of individual DISARM genes and that the absence of methylase genes drmMI and drmMII does not result in autoimmunity. In addition to antiphage activity we also observe that DISARM limits conjugation, and this activity is linked to the number of methylase cognate sites in the plasmid. Overall, we show that Class 1 DISARM provides robust anti-phage and anti-plasmid protection mediated primarily by drmA and drmB, which provide resistance to invading nucleic acids using a mechanism enhanced by the recognition of unmethylated cognate sites of the two methylases drmMI and drmMII.

microbiology↗