A microbial community that alters mitochondrial morphology and age-related motor function in C. elegans

Across diverse taxa, the composition of the microbiota is associated with host fitness. A mechanistic understanding of how microbial communities influence host physiology could lead to microbiota-based interventions for lifelong health. Here, we have developed a host-microbiota model system consisting of the model organism <i>C. elegans</i> combined with a defined natural microbiota (DefNatMta) consisting of 11 bacterial strains isolated from wild <i>C. elegans</i> to study natural host-microbiota interactions in the laboratory. We show that DefNatMta persists in the <i>C. elegans</i> gut, forming a stable and distinct gut microbiota. Utilizing this host-microbiota system, we find that DefNatMta affects age-related motility and protects against age-related decline in motor function. DefNatMta acts by altering metabolism and mitochondrial network dynamics in muscle and requires dynamin-related protein 1 (DRP-1), a regulator of mitochondrial fission to protect against age-related motility decline. Our findings are consistent with microbe-mitochondria communication affecting age-related muscle function.