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Abstract
Microbial communities are responsible for global and local chemical cycling in the environment and in association with larger organisms. Microbial communities found in the digestive system of animals play particularly important roles in the health of their host. However, our understanding of forces driving microbial community dynamics and stability in these complex ecosystems is limited.The American cockroach is an omnivorous insect with complex microbial community found in its hindgut that contains lineages related to those found in mammalian omnivores, although with phylogeny indicating an evolutionary history of insect association. As these organisms are represented by few published isolates, our ability to infer the functional potential of these microbes is limited. To characterize phylogenetic and functional aspects of these taxa in vivo, we sequenced 96 high-quality single cell-amplified genomes (SAGs) of cockroach gut microbes and mapped hindgut metagenome and metatranscriptome sequence libraries to our SAGs. Our results provide a valuable set of cockroach-specific reference genomes and uncovers new insights in functional specializations of taxa found here and creates a framework for future studies of stability in hindgut metabolism.
Diet-shift studies of the 16S rRNA gene profile in the hindgut of the American cockroach have revealed remarkable stability of this community. To discover sources of this stability, we analyzed transcriptional activities of microbial groups in cockroaches on diets with divergent nutritional profiles. We discovered that dietary complex carbohydrate and fat content were drivers of community’s response, including its overall stability and transcribed functions. These results uncover dynamic activities underlying the homeostasis of the cockroach gut microbiome and introduce avenues for furthering our understanding of stability in this environment.