A functional circadian clock regulates composition and daily bacterial load of the gut microbiome inDrosophila melanogaster

Abstract

AbstractWhileDrosophila melanogasterserves as a crucial model for investigating both the circadian clock and gut microbiome, our understanding of their relationship in this organism is still limited. Recent analyses suggested that theDrosophilagut microbiome modulates the host circadian tran-scriptome to minimize rapid oscillations in response to changing environments. To delve deeper into the potential relationship between the gut microbiota and circadian clock inDrosophila, we examined the composition and abundance of the gut microbiota in wild-type and arrhythmicper01flies, under 12 h:12 h light: dark (12:12 LD) and constant darkness (DD) conditions. The gut microbiota of wild-type andper01flies showed differences in composition, suggesting that theD. melanogastercircadian clock has a role in shaping the gut microbiome. In 12:12 LD and DD conditions,per01mutants showed significant daily variations in gut bacterial quantity, unlike wild-type flies. This suggests that the circadian clock inD. melanogasterplays a role in maintaining daily stability in gut microbiome load. Finally, some gut bacteria exhibited significant 24 h fluctuations in their relative abundance, which appeared independent from the fly circadian clock, suggesting that certain gut commensal bacteria inDrosophilamay possess a host-independent circadian clock.