The honey bee, a model organism for exploring epigenomic mechanisms in immune priming inheritance

Abstract

Invertebrates were thought to rely only in their innate immune system to combat infections. However, recent findings show that Immune Priming (IP), a phenomenon that allows invertebrates to enhance their immune response against a previously encountered pathogen, provides long-term protective effects not only in the primed individuals but also their offspring. Alterations in gene expression patterns and their inheritance are likely mediated by epigenetic mechanisms, but mechanistic details are unknown. Therefore, the aim of this proposal is to investigate how IP is generated and inherited at molecular and behavioral levels. To this end, the highly eusocial honey bee, Apis mellifera, will be used as a model organism to study the potential physiological costs of IP on reproduction and behavior. First, the specificity, duration, and costs of IP on honey bee reproduction will be determined. Next, a list of differentially expressed genes will be generated by sequencing the brain transcriptomes of primed and control workers. This information will be contrasted with chromatin maps for histone post-translational modifications associated with IP. Finally, behavioral assays will determine whether IP affects the social organization of honey bees. With these latter experiments, we will determine, for the first time in any invertebrate, whether changes in social behavior driven by IP are in fact inherited. Therefore, this project represents a first effort to understand how IP is not only reflected in chromatin reprogramming to regulate gene expression, but also whether and how it can be inherited in a model organism of social insects. (AU)