|Title||Gene and genome-centric analyses of koala and wombat fecal microbiomes point to metabolic specialization for Eucalyptus digestion|
|Publication Type||Journal Article|
|Year of Publication||2017|
|Authors||Shiffman ME, Soo RM, Dennis PG, Morrison M, Tyson GW, Hugenholtz P|
|Keywords||Eucalyptus, Herbivory, Koala, Marsupials, Metagenomics, Microbiome, PSM, Wombat|
The koala has evolved to become a specialist \textitEucalyptus herbivore since diverging from its closest relative, the wombat, a generalist herbivore. This niche adaptation involves, in part, changes in the gut microbiota. The goal of this study was to compare koala and wombat fecal microbiomes using metagenomics to identify potential differences attributable to dietary specialization. Several populations discriminated between the koala and wombat fecal communities, most notably \textitS24-7 and \textitSynergistaceae in the koala, and \textitChristensenellaceae and \textitRF39 in the wombat. As expected for herbivores, both communities contained the genes necessary for lignocellulose degradation and urea recycling partitioned and redundantly encoded across multiple populations. Secondary metabolism was overrepresented in the koala fecal samples, consistent with the need to process \textitEucalyptus secondary metabolites. The \textitSynergistaceae population encodes multiple pathways potentially relevant to \textitEucalyptus compound metabolism, and is predicted to be a key player in detoxification of the koala’s diet. Notably, characterized microbial isolates from the koala gut appear to be minor constituents of this habitat, and the metagenomes provide the opportunity for genome-directed isolation of more representative populations. Metagenomic analysis of other obligate and facultative \textitEucalyptus folivores will reveal whether putatively detoxifying bacteria identified in the koala are shared across these marsupials.