ABSTRACT
Under specific circumstances, symbiotic bacteria can cause fulminant, and potentially life-threatening disease in animal hosts. Despite the relevance of symbiont containment for prolonged health, we know very little about the basis for symbiont-dependent disease. We used the Drosophila model to examine the impacts of individual symbiotic species on host longevity. In this study, we found that mono-association of adult Drosophila with Lactobacillus plantarum, a widely reported fly symbiont, and member of the probiotic Lactobacillus genus, curtails adult longevity and causes extensive intestinal pathology within the host. Intestinal disease includes impaired epithelial renewal, a loss of intestinal stem cells, and a gradual erosion of epithelial integrity. Our study uncovers a previously unknown pathogenic aspect of Lactobacillus plantarum association with Drosophila and establishes a simple model for the mechanistic exploration of the biology of symbiont-mediated disease.