Cross-kingdom Interactions between Candida albicans and Enterococcus faecalis in the Gut Microbiome

Candida albicans and Enterococcus faecalis are both common members of the human gut microbiome. Previous studies have suggested that this yeast and bacteria species interact as commensal members in the gut, however the mechanisms behind these interactions have yet to be elucidated. By measuring gene expression of these species in co-culture, we can start to tease apart the genetic underpinnings of this interaction. Using Dual RNA-seq, we characterized the transcriptional profiles of both C. albicans and E. faecalis during growth together and separately in two conditions – 1) gut-like in-vitro culture and 2) Germ-free (GF) mouse gut. The transcriptional response of C. albicans to E. faecalis is very similar across in vitro and GF gut conditions, with over 300 genes up-regulated > 4-fold in either condition. Up-regulated genes include a group of seven transcription factors which are induced exclusively in the presence of E. faecalis. Many of these transcription factors are currently uncharacterized, indicating a possible function in mediating interkingdom interactions with bacteria in biologically relevant environments, such as the gut. Future work is ongoing to determine the transcriptional networks controlled by these upregulated transcription factors and the role of those networks in the interactions between Candida albicans and Enterococcus faecalis.