Gut physiology mediates a trade-off between adaptation to malnutrition and susceptibility to food-borne pathogens
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.
Keywords: Adaptation ; Drosophila ; enteric infections ; experimental evolution ; host-parasite interactions ; innate immunity ; nutritional stress ; Pseudomonas entomophila ; stress tolerance ; trade-offs
Record created on 2015-12-02, modified on 2016-08-09