Postdoctoral Research Associate in Evolution of Host–Microbe Symbioses - QMUL Jobs

ID: 10612. Title: Postdoctoral Research Associate in Evolution of Host–Microbe Symbioses. Application Deadline:

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Mobility shapes plasmid GC content evolution

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

doi.org

How to give a bad talk - Nature Reviews Cancer

Effective presentations require clarity and audience awareness. In this Comment, Itai Yanai outlines common misconceptions about presentations and how to address them to deliver more impactful and ins...

nature.com

Why does altruism exist? at University College London on FindAPhD.com

PhD Project - Why does altruism exist? at University College London, listed on FindAPhD.com

findaphd.com

OrthoFinder: improved phylogenetic orthology inference with enhanced accuracy and scalability - Nature Methods

The updated OrthoFinder v3 software boosts accuracy and scalability in phylogenetic orthology inference with massive and diverse datasets.

nature.com

Social immunity can be a consequence and cause of social evolution | PNAS

Many social insects respond to pathogens in ways that reduce pathogen transmission within their social groups, with behaviors such as grooming or r...

pnas.org

Professors Tim Coulson, Stuart West, and Kathy Willis elected as Fellows of the Royal Society

biology.ox.ac.uk

Job Details

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Bacterial weaponry and the ecological factors of competitive success

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...

portlandpress.com

How social is social resistance?

Abstract. β-lactamases are central to bacterial resistance against β-lactam antibiotics and are often treated as a textbook example of cooperative resistance. The cooperative aspect of their action ar...

portlandpress.com

Career Opportunities: Postdoctoral positions in predictive modelling of antibiotic resistance spread (22755)

tinyurl.com

biorxiv.org

Phenotypic divergence is driven by mobile genetic elements in a heritable insect symbiont

Heritable microbes profoundly influence insect biology, yet the traits they confer often evolve rapidly and differ among closely related symbiont strains. Despite their importance, we lack a clear understanding of how novel traits arise in symbiosis and how this diversity influences host ecology in natural populations. The aphid facultative symbiont Regiella insecticola is ideally suited to this question because of its strong lineage-specific variation in host benefits. By generating 20 high-quality genomes, we found that Regiella ’s evolution is driven largely by gene gains mediated by mobile genetic elements. We identified a plasmid (pRILSR1) that encodes a type IV secretion system and a highly expressed predicted effector that has been convergently acquired by Regiella strains from pea aphids. Notably, only pRILSR1-bearing strains confer protection against the specialist fungal pathogen Pandora neoaphidis , indicating that gains and losses of the plasmid underlie the evolution of this key defensive phenotype. Using a multi-year field study, we further show that the pRILSR1 plasmid is strongly associated with Regiella found in pea aphid populations adapted to specific host plants, driving variation in symbiont-mediated defense across populations. Together, our results show that mobile genetic elements generate key adaptive traits in microbial symbionts and, in doing so, drive phenotypic divergence among host populations. ### Competing Interest Statement The authors have declared no competing interest.

biorxiv.org

Community conservatism is widespread across microbial phyla and environments - Nature Ecology & Evolution

This study reveals that closely related microorganisms tend to inhabit similar communities across all major environments and phyla. The authors term this phenomenon ‘community conservatism’, extending...

nature.com

Job profile

hrwebapp.qub.ac.uk

Bacterial immune systems as causes and consequences of microbiome structure

Bacterial immune systems have evolved in response to diverse molecular "parasites", yet their ecological roles remain poorly understood. This Essay explores how interactions between mobile genetic ele...

journals.plos.org

findaphd.com

MRC DiMeN Doctoral Training Partnership: Resistant zombies: how drug-resistance plasmids manipulate the behaviour of the opportunistic pathogen Pseudomonas aeruginosa at University of Liverpool on Fin...

PhD Project - MRC DiMeN Doctoral Training Partnership: Resistant zombies: how drug-resistance plasmids manipulate the behaviour of the opportunistic pathogen Pseudomonas aeruginosa at University of Li...

findaphd.com

PhyloWeaver – Interactive phylogenetic tree editor

Edit and visualize phylogenetic trees directly in your browser. PhyloWeaver lets you interactively rearrange tree topologies and export high-quality figures for publications and presentations.

yawak.jp