All animals are colonized by microorganisms that play an important but poorly-understood role in sustaining the health and fitness of their animal host. The fruit fly Drosophila melanogaster and related drosophilid flies offer uniquely tractable systems to study how animals interact with their resident microbiota.
We have demonstrated that the microbiota in drosophilid flies is of low diversity, dominated by readily-culturable bacteria. Our experiments using axenic (germ-free) flies and flies bearing specific bacteria have revealed the pervasive effects of the microbiota on nutritional health. Certain bacterial species and bacterial communities promote host growth and development, protect the host against excessive lipid accumulation on high-sugar diets, and provide B vitamins important for host health on low-nutrient diets.
We are using the natural genetic variation in both Drosophila and its bacterial partners to identify the host and microbial genes that influence the composition of the microbiota and their effects on host nutritional health. Genome-wide association studies (GWAS) using flies from the Drosophila Genetic Reference Panel and metagenome-wide association studies (MGWAS) of Drosophila colonized by different bacteria are revealing candidate genes that we are validating.
In parallel, we are interrogating the microbiota in natural populations of Drosophila species and the relationship between the taxonomic diversity of the microorganisms and the functional traits of both the microbiota and the host. These analyses provide the mechanistic underpinning to understand how the microbiota influence ecologically-important traits of their insect hosts, including food choice, competitive interactions and susceptibility to pathogens and parasites.
Selected Recent Publications
Dobson AD, Chaston JM and Douglas AE 2016. The Drosophila transcriptional network is structured by microbiota. BMC Genomics 17, 975.
Adair KL and Douglas AE 2016. Making a microbiome: The many determinants of host-associated microbial community composition. Current Opinion in Microbiology 35, 23-29.
Chaston JM, Dobson AJ, Newell PD and Douglas AE 2015. Hostgenetic control of the microbiota mediates Drosophila nutritional phenotype. Applied and Environmental Microbiology 82, 671-9.
Overend G, Luo Y, Henderson L, Douglas AE and Dow JAT. 2016. Molecular mechanism and functional significance of acid generation in the Drosophila midgut. Scientific Reports 6, 27242.
Chaston JM, Dobson AJ, Newell PD and Douglas AE 2016. Host genetic control of the microbiota mediates Drosophila nutritional phenotype. Applied and Environmental Microbiology 82, 671-9.
Huang J-H and Douglas AE 2015. Consumption of dietary sugar by gut bacteria determines Drosophila lipid content. Biology Letters 11, 20150469.
Wong C-N*, Luo Y*, Jing X, Franzenburg S, Bost A and Douglas AE 2015. The host as driver of the microbiota in the gut and external environment of Drosophila melanogaster. Applied and Environmental Microbiology 81, 6232-6240.
Dobson AJ*, Chaston JM*, Newell PD, Donahue L, Hermann SL, Sannino DR, Westmiller S, Wong C-N, Clark AG, Lazzaro BP and Douglas AE 2015. Host genetic determinants of microbiota-dependent nutrition revealed by genome-wide analysis of Drosophila melanogaster. Nature Communications 6, 6312.
For financial support of our research on Drosophila and its microbiome, we thank:
NSF BIO 1241099 Animal-microbial interactions as an engine of phylogenetic and functional diversity (with J. Jaenike and G. Loeb, current)