CONICET | Buscador de Institutos y Recursos Humanos

Caenorhabditis elegans, encounters a wide variety of microbes including yeasts in its natural habitat. Some benign and others pathogenic that reduce lifespan andfecundity. When C. elegans consumes a pathogen, its intestine is colonized which mounts an immune response to eliminate clear the infection and restore normalphysiological activities. In parallel, the nervous system is also activated, allowing the nematode to escape the pathogen. Pathogen avoidance is not only a learnedbehavior but also one that is transmitted to the progeny. We leverage the powerful genetics and simple systems of C. elegans to study hostmicrobialinteractions. Presenting a choice of microbial foods to naïve C. elegans wediscovered that worms initially prefer Candida albicans over nonpathogenic,Escherichia coli (OP50), or even the pathogenic bacteria Pseudomonas aeruginosa.Subsequently, within 68hrs., nematodes sense the C. albicans infection and, in parallel with the immune activation, display aversive behavior to escape C. albicans.We observed that the ASI sensory neurons promote this aversive behavior. Furthermore, worms that are trained for 24 hrs. on C. albicans learn to avoid C. albicansand lose the preference for C. albicans. Interestingly, this learned avoidance behavior is transmitted to the progeny for at least two generations. Our studies integrate twokey biological systems, innate immunity, and neural network, with environmental cues of infection and provide a systems level understanding of the hostmicroberelationship over multiple generations. These studies inform how the memory of pathogenic stress is inherited and how such population level decisions increase hostsurvival in fluctuating environmental conditions.