Metabolic cooperation among commensal bacteria supportsDrosophilajuvenile growth under nutritional stress

SUMMARYThe gut microbiota shapes animal growth trajectory in stressful nutritional environments, but the molecular mechanisms behind such physiological benefits remain poorly understood. The gut microbiota is mostly composed of bacteria, which construct metabolic networks among themselves and with the host. Until now, how the metabolic activities of the microbiota contribute to host juvenile growth remains unknown. Here, usingDrosophilaas a host model, we report that two of its major bacterial partners,Lactobacillus plantarumandAcetobacter pomorumengage in a beneficial metabolic dialogue that boosts host juvenile growth despite nutritional stress. We pinpoint that lactate, produced byL. plantarum, is utilized byA. pomorumas an additional carbon source, andA. pomorumprovides essential amino-acids and vitamins toL. plantarum. Such bacterial cross-feeding provisions a set of anabolic metabolites to the host, which may foster host systemic growth despite poor nutrition.GRAPHICAL HIGHLIGHTSL. plantarumfeeds lactate toA. pomorumA. pomorumsupplies essential amino acids and vitamins toL. plantarumMicrobiota metabolic dialogue boosts Drosophila’s larval growthLactate utilization byAcetobacterreleases anabolic metabolites to larvae