Translation dynamics during the innate immune response in Tribolium castaneum flour beetles

Immune dynamics during early acute infection drive disease outcomes. Upon detection of a parasitic threat, hosts activate signal transduction pathways to trigger the expression of immune effectors, the ‘first responders’ against parasite threats. While a rapid, robust, and effective activation of the host immune response is necessary to quell infection, the expression of immune effectors is costly and may result in auto-immune damage. Transcriptomic techniques have revealed thousands of genes underlying the molecular dynamics of the insect immune response, but these transcripts are still many steps away from being functional immune effectors, and cells struggle to meet this protein production demand. Deciding which transcripts to translate can then be life-or-death decisions during infection. We therefore investigated the role of differential translation and efficiency as an immune response modulator and mechanism for infection resistance in the red flour beetle (Tribolium castaneum). We adapted recent techniques in ribosome profiling (Riboseq), which selectively purify ribosome-bound transcripts to assess differential expression at the level of protein synthesis. Paired with full mRNA sequencing, Riboseq can be used to examine translation efficiency dynamics during early immune response across natural populations of beetles which vary in their susceptibility across different parasites. We are able to capture active translation of immune effectors in infected versus uninfected adults in early acute infection, and further report on considerations for method adaptation in other species.