Microbiome modulation in regeneration in jellyfish.

The moon jelly Aurelia coerulea does not typically regenerate appendages. A previous study found that increasing nutrient availability promotes the activation of appendage regeneration. In this study, we found that changes in nutrient availability alter microbiome composition. Genome-scale metabolic modeling of the microbial symbionts suggests that the microbiome modulation reduces the abundance of a symbiont that competes with the host for metabolic resources. Antibiotic treatment that recapitulates the microbiome shift significantly promotes regeneration. Transcriptomic analysis of the host shows an upregulation of genes involved in the arginine biosynthetic pathway, including argininosuccinate synthase and carbamoyl phosphate synthase. Exogenous arginine supplementation promotes appendage regeneration. These findings suggest that microbiome composition, influenced by nutrient availability, contributes to the activation of host regeneration, and identify a role for arginine in promoting regeneration.