ORCID Profile
0000-0003-1393-9220
Current Organisation
University of Oxford
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Publisher: Wiley
Date: 10-2019
DOI: 10.1002/ECE3.5704
Publisher: Springer Science and Business Media LLC
Date: 15-11-2016
DOI: 10.1038/NCOMMS13430
Abstract: Microbes that protect their hosts from pathogens are widespread in nature and are attractive disease control agents. Given that pathogen adaptation to barriers against infection can drive changes in pathogen virulence, ‘defensive microbes’ may shape disease severity. Here we show that co-evolving a microbe with host-protective properties ( Enterococcus faecalis ) and a pathogen ( Staphylococcus aureus ) within Caenorhabditis elegans hosts drives the evolution of reduced pathogen virulence as a by-product of adaptation to the defensive microbe. Using both genomic and phenotypic analyses, we discover that the production of fewer iron-scavenging siderophores by the pathogen reduces the fitness of the defensive microbe and underpins the decline in pathogen virulence. These data show that defensive microbes can shape the evolution of pathogen virulence and that the mechanism of pathogen resistance can determine the direction of virulence evolution.
Publisher: Public Library of Science (PLoS)
Date: 08-04-2016
Publisher: Cold Spring Harbor Laboratory
Date: 02-05-2023
DOI: 10.1101/2023.05.02.539033
Abstract: Endosymbiosis – where a microbe lives and replicates within a host – is an important contributor to organismal function that has accelerated evolutionary innovations and catalysed the evolution of complex life. The evolutionary processes associated with transitions to endosymbiosis, however, are poorly understood. Here, we use comparative genomics of the genus Arsenophonus to reveal the complex processes that occur on evolution of an endosymbiotic lifestyle. We compared the genomes of 38 strains spanning erse lifestyles from environmentally acquired infections to obligate inter-dependent endosymbionts. We observed recent endosymbionts had larger genome sizes than closely related environmentally acquired strains, consistent with evolutionary innovation and rapid gain of new function. Increased genome size was a consequence of prophage and plasmid acquisition including a cargo of type III effectors, and concomitant loss of CRISPR-Cas genome defence systems enabling mobile genetic element expansion. Persistent endosymbiosis was also associated with loss of type VI secretion, likely reflecting reduced microbe-microbe competition. Thereafter, the transition to stable endosymbiosis and vertical inheritance was associated with the expected relaxation of purifying selection, pseudogenisation of genes and reduction of metabolism, leading to genome reduction. However, reduced %GC that is typically considered a progressive linear process was observed only in obligate interdependent endosymbionts. We argue that a combination of the need for rapid horizontal gene transfer-mediated evolutionary innovation together with reduced phage predation in endosymbiotic niches drives loss of genome defence systems and rapid genome expansion upon adoption of endosymbiosis. These remodelling processes precede the reductive evolution traditionally associated with adaptation to endosymbiosis.
Publisher: Wiley
Date: 05-12-2016
DOI: 10.1111/MEC.13906
Publisher: Springer Science and Business Media LLC
Date: 18-02-2021
DOI: 10.1038/S41396-021-00911-3
Abstract: Pathogens continue to emerge from increased contact with novel host species. Whilst these hosts can represent distinct environments for pathogens, the impacts of host genetic background on how a pathogen evolves post-emergence are unclear. In a novel interaction, we experimentally evolved a pathogen ( Staphylococcus aureus ) in populations of wild nematodes ( Caenorhabditis elegans ) to test whether host genotype and genetic ersity affect pathogen evolution. After ten rounds of selection, we found that pathogen virulence evolved to vary across host genotypes, with differences in host metal ion acquisition detected as a possible driver of increased host exploitation. Diverse host populations selected for the highest levels of pathogen virulence, but infectivity was constrained, unlike in host monocultures. We hypothesise that population heterogeneity might pool together in iduals that contribute disproportionately to the spread of infection or to enhanced virulence. The genomes of evolved populations were sequenced, and it was revealed that pathogens selected in distantly-related host genotypes erged more than those in closely-related host genotypes. S. aureus nevertheless maintained a broad host range. Our study provides unique empirical insight into the evolutionary dynamics that could occur in other novel infections of wildlife and humans.
Publisher: Springer Science and Business Media LLC
Date: 15-03-2016
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Kayla King.