Author(s): L'Amat Rosales, Sarah J. Gottfredson Morgan, Brittany S. Burnside
Mentor(s): John Chaston
Institution BYU
We sought to better understand how diet and microbiota interactions shape fundamental aspects of health, development, and adaptability. We examined how different fruit and vegetable diets impact the microbiota composition and life history traits of D. melanogaster flies reared under varying microbial treatments. The treatments were axenic (bacteria-free), conventional (natural microbiome), and gnotobiotic (inoculated with specific bacterial strains) flies. Then, to determine how the diets influenced the phenotypes of the flies under these conditions, we measured fly development times and starvation resistance, two readily-measured traits that reflect the flies’ life history. We also sequenced the flies microbiota, which is known to influence their life history traits. Fly development times varied with diet and microbial treatment, with axenic flies showing slower development rates, while conventional and gnotobiotic flies showed diet-dependent differences in development time. Many conventional flies developed faster than gnotobiotic flies on several diets, suggesting a microbiome-driven effect on life history traits. There were also significant diet and microbial treatment influences on fly starvation resistance. Studying the microbiota using 16S rRNA sequencing showed that each diet also shaped the microbial community composition, and identified microbial amplicon sequence variants that varied significantly in response to diet. These results show that the combination of the different diets and microbial treatments resulted in distinct changes to microbial community composition as well as development and starvation resistance. Taken together, our results support the expectation that diet-microbiota interactions are important determinants of fly fitness. They also emphasize that feeding on different diets is likely to have consequences on the flies’ adaptive responses to their wild environments.