Speaker
Description
Beetles have a hard cuticle that protects them against biotic and abiotic threats. Tyrosine is essential for cuticle synthesis but insects cannot synthesize it and must obtain it with their diet. Our study investigates the symbiotic relationship between Dinoderus porcellus and its two bacterial symbionts focusing on their contribution to the host’s cuticle development. The symbiont Shikimatogenerans retained the shikimate pathway that produces the precursor of tyrosine. The second symbiont, Bostrichidicola, retained genes involved in urea recycling and the biosynthesis of lysine. We assessed the symbionts’ contribution to the host by supplementing the beetle’s diet with antibiotics or inhibitors of metabolic pathways, then evaluating the effects on symbiont titers, cuticle thickness, and pigmentation. Antibiotics and glyphosate significantly reduced Shikimatogenerans titers and compromised cuticle pigmentation, supporting our hypothesis that the host benefits from symbiont-derived tyrosine precursors. Inhibitor of lysine metabolic pathway resulted in increased Bostrichidicola titers but no cuticle changes, suggesting its alternative roles for host metabolism. Furthermore, injection of 15N-urea into resulted in broad incorporation of the 15N-label into adults’ amino acids attesting to the importance of Bostrichidicola ability to recycle nitrogen and potential tripartite metabolite exchange although not necessarily in the context of cuticle synthesis.
