A1 Journal article (refereed)
Broad thermal tolerance is negatively correlated with virulence in an opportunistic bacterial pathogen (2018)

Ashrafi, R., Bruneaux, M., Sundberg, L.-R., Pulkkinen, K., Valkonen, J., & Ketola, T. (2018). Broad thermal tolerance is negatively correlated with virulence in an opportunistic bacterial pathogen. Evolutionary Applications, 11(9), 1700-1714. https://doi.org/10.1111/eva.12673

JYU authors or editors

Publication details

All authors or editors: Ashrafi, Roghaieh; Bruneaux, Matthieu; Sundberg, Lotta-Riina; Pulkkinen, Katja; Valkonen, Janne; Ketola, Tarmo

Journal or series: Evolutionary Applications

ISSN: 1752-4571

eISSN: 1752-4571

Publication year: 2018

Volume: 11

Issue number: 9

Pages range: 1700-1714

Publisher: Wiley-Blackwell Publishing, Inc.

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1111/eva.12673

Research data link: https://doi.org/10.5061/dryad.858j5m7

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/60061

Abstract

Predicting the effects of global increase in temperatures on disease virulence is challenging, especially for environmental opportunistic bacteria, because pathogen fitness may be differentially affected by temperature within and outside host environment. So far, there is very little empirical evidence on the connections between optimal temperature range and virulence in environmentally growing pathogens. Here, we explored whether the virulence of an environmentally growing opportunistic fish pathogen, Flavobacterium columnare, is malleable to evolutionary changes via correlated selection on thermal tolerance. To this end, we experimentally quantified the thermal performance curves (TPCs) for maximum biomass yield of 49 F. columnare isolates from eight different geographic locations in Finland over ten years (2003–2012). We also characterized virulence profiles of these strains in a zebra fish (Danio rerio) infection model. We show that virulence among the strains increased over the years, but thermal generalism, and in particular tolerance to higher temperatures, was negatively associated with virulence. Our data suggest that temperature has a strong effect on the pathogen genetic diversity and therefore presumably also on disease dynamics. However, the observed increase in frequency and severity of F. columnare epidemics over the last decade cannot be directly linked to bacterial evolution due to increased mean temperature, but is most likely associated with factors related to increased length of growing season, or other time‐dependent change in environment. Our study demonstrates that complex interactions between the host, the pathogen and the environment influence disease virulence of an environmentally growing opportunistic pathogen.

Keywords: pathogens; bacteria; virulence; heat resistance; climate changes

Free keywords: thermal tolerance; opportunistic pathogen; thermal performance curves; climate change

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Ministry reporting: Yes

VIRTA submission year: 2018

JUFO rating: 1