Pseudomonas aeruginosa employs a repertoire of TonB-dependent transporters (TBDTs) to acquire essential nutrients, such as iron-siderophore complexes, enabling its adaptation to diverse and often host...

Plasmids are frequently AT-rich relative to their bacterial hosts. Despite this tendency towards lower GC content, plasmid and host chromosome GC content are positively correlated across diverse collections of plasmid-host pairs. However, the evolutionary processes underlying this pattern remain unclear. The classic model of amelioration predicts that horizontally acquired DNA gradually converges on host nucleotide composition. However, because plasmids can repeatedly transfer between bacterial hosts, the opportunity for such host-associated evolution may depend on their transmission dynamics. Using 50,936 plasmid-host pairs from a public sequence database, we found that the apparent global correlation between plasmid and host chromosome GC content was largely driven by differences between bacterial species rather than within species. We therefore accounted for plasmid and host population structure when testing how plasmid mobility shaped host-associated compositional evolution. We compared two contrasting regimes: a population of 3,682 Enterobacterales plasmids distributed across diverse host backgrounds, and six long-term host-associated plasmids from a Rhizobium leguminosarum lineage with INSeq-determined gene essentiality data. In the Enterobacterales population, GC content variation was overwhelmingly explained by plasmid lineage rather than host phylogeny, and conjugative plasmids showed greater similarity to their host chromosomes than mobilisable or non-mobilisable plasmids. In the Rhizobium leguminosarum plasmids, synonymous-site composition was more similar to the host chromosome among genes required across multiple host life stages. Together, these results support a model in which plasmid mobility influences the opportunity for host-associated evolutionary processes to alter nucleotide composition. ### Competing Interest Statement The authors have declared no competing interest. Wellcome Trust, 319534/Z/24/Z St. John's College, University of Oxford, UK

Abstract. Bacteria have evolved complex protein systems known as bacterial weapons to inhibit or kill their competitors. These bacterial weapons are a remarkably diverse arsenal that influence the com...

PhD Project - Investigating how E. coli exploits bacterial competition in the microbiome at University of Reading, listed on FindAPhD.com

Bacteriocins are toxins deployed by bacteria to kill their competitors. Here, I reflect on my laboratory’s work on protein bacteriocins and their immunity proteins from Gram-negative bacteria. We unco...

Abstract. Salmonella enterica, a prominent enteric pathogen, employs sophisticated iron acquisition mechanisms to overcome host-imposed iron limitation, no

Mathematical modelling and experimental tests reveal principles that govern displacement of a resident strain by an invader in microbial communities.

Bacteria employ a range of competition systems that deliver toxins to inhibit competing strains. This study shows that these systems are particularly important for the ecology of virulent and antibiot...