Conditionally pathogenic gut microbes promote larval growth by increasing redox-dependent fat storage in high sugar diet-fed Drosophila melanogaster. High sugar diet fed fly

Recent evidences suggest the development of obesity and subsequent complications associated with metabolic syndrome might be a consequence of gut microbial alterations. However, the impact of gut microbial alteration and potential role of increasing bacterial species during the progress of obesity still remain unclear. Here, we show that chronic feeding of high sugar diet (HSD) resulted in dominance of resident uracil-secreting bacteria in the gut of Drosophila melanogaster. Both mono-associations of the uracil-secreting bacteria and uracil supplementation to axenic animals enhance larval development on HSD. Redox signaling induced by bacterial uracil promotes larval growth by regulating sugar and lipid metabolisms through activation of p38a MAPK. These results provide a new mechanism for the redox dependent host protective role of the uracil-secreting bacteria, previously known as opportunistic pathobionts, on host metabolic perturbation.