Host adaptation is contingent upon the infection route taken by pathogens

PLoS Pathog. 2013;9(9):e1003601. doi: 10.1371/journal.ppat.1003601. Epub 2013 Sep 26.

Abstract

Evolution of pathogen virulence is affected by the route of infection. Also, alternate infection routes trigger different physiological responses on hosts, impinging on host adaptation and on its interaction with pathogens. Yet, how route of infection may shape adaptation to pathogens has not received much attention at the experimental level. We addressed this question through the experimental evolution of an outbred Drosophila melanogaster population infected by two different routes (oral and systemic) with Pseudomonas entomophila. The two selection regimes led to markedly different evolutionary trajectories. Adaptation to infection through one route did not protect from infection through the alternate route, indicating distinct genetic bases. Finally, relatively to the control population, evolved flies were not more resistant to bacteria other than Pseudomonas and showed higher susceptibility to viral infections. These specificities and trade-offs may contribute to the maintenance of genetic variation for resistance in natural populations. Our data shows that the infection route affects host adaptation and thus, must be considered in studies of host-pathogen interaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological / immunology*
  • Animals
  • Drosophila melanogaster
  • Immunity, Innate*
  • Pseudomonas / immunology*
  • Pseudomonas Infections / genetics
  • Pseudomonas Infections / immunology*

Grants and funding

This work was supported by the Fundação para a Ciência e a Tecnologia (FCT, Portugal) funds NM (#SFRH/BPD/62964/2009) and VF (#SFRH/BD/82299/2011). This work was supported by Instituto Gulbenkian de Ciência/Fundação Calouste Gulbenkian and FCT (#POCTI/BIA -BDE/60950/2004) to ES. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.