title: Gut physiology mediates a trade-off between adaptation to malnutrition and susceptibility to food-borne pathogens.
abstract: The animal gut plays a central role in tackling two common ecological challenges, nutrient shortage and food-borne parasites, the former by efficient digestion and nutrient absorption, the latter by acting as an immune organ and a barrier. It remains unknown whether these functions can be independently optimised by evolution, or whether they interfere with each other. We report that Drosophila melanogaster populations adapted during 160 generations of experimental evolution to chronic larval malnutrition became more susceptible to intestinal infection with the opportunistic bacterial pathogen Pseudomonas entomophila. However, they do not show suppressed immune response or higher bacterial loads. Rather, their increased susceptibility to P. entomophila is largely mediated by an elevated predisposition to loss of intestinal barrier integrity upon infection. These results may reflect a trade-off between the efficiency of nutrient extraction from poor food and the protective function of the gut, in particular its tolerance to pathogen-induced damage.
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, CH, 1015, Lausanne, Switzerland.
authors.forename: Roshan K
authors.initials: RK
authors.lastname: Vijendravarma
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, CH, 1015, Lausanne, Switzerland.
authors.forename: Sunitha
authors.initials: S
authors.lastname: Narasimha
authors.affiliation: Global Health Institute, EPFL, CH 1015, Lausanne, Switzerland.
authors.forename: Sveta
authors.initials: S
authors.lastname: Chakrabarti
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, CH, 1015, Lausanne, Switzerland.
authors.forename: Aurelie
authors.initials: A
authors.lastname: Babin
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, CH, 1015, Lausanne, Switzerland.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Kolly
authors.affiliation: Global Health Institute, EPFL, CH 1015, Lausanne, Switzerland.
authors.forename: Bruno
authors.initials: B
authors.lastname: Lemaitre
authors.affiliation: Department of Ecology and Evolution, University of Lausanne, CH, 1015, Lausanne, Switzerland.
authors.forename: Tadeusz J
authors.initials: TJ
authors.lastname: Kawecki
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D058491:Bacterial Load; D005075:Biological Evolution; D004198:Disease Susceptibility; D004331:Drosophila melanogaster / Q000276:immunology / Q000382:microbiology / Q000502:physiology*; D007422:Intestines / Q000382:microbiology / Q000502:physiology*; D007814:Larva / Q000502:physiology; D044342:Malnutrition; D011549:Pseudomonas
keywords: Adaptation; Drosophila; Pseudomonas entomophila; enteric infections; experimental evolution; host-parasite interactions; innate immunity; nutritional stress; stress tolerance; trade-offs