Meeting Abstract
The vertebrate gut microbiota plays key defensive roles by stimulating host immunity and by direct interactions with pathogens. For examples, colonization of the gut by mutualistic microbes is essential for the normal maturation of the vertebrate immune system, particularly the immune response and some microbes competitively exclude pathogens or pathobionts via interference or exploitative competition. However, multiple genes are associated with immune function and microbiota community structure, which can complicate the study of this system. Detangling the complexities of this host-microbiota relationship is important to understanding how vertebrates defend against enteric pathogens. However, many laboratory models used to study host-microbiota interactions use inbred models that lack genetic diversity, which may constrain inference regarding intra- and interpopulation differences in immune responses and pathogen susceptibility. In order to account for the effect of genetic background, we use threespine stickleback (Gasterosteus aculeatus) as a model species, because multiple populations of freshwater stickleback have evolved in isolation from common, anadromous ancestors and thus exhibit the high degrees of genetic variation. We raised two populations of stickleback in both germ-free conditions and in the presence of naturally occurring microbes and exposed them to a pathogen (Vibrio anguillarum) in a full factorial design. We measured how these treatments affected survival, immune gene expression, morphological development, and behavior. Our studies will elucidate the role of the host genetic background in the ability of the microbiota to protect the host from pathogens.
