Transcriptional landscape of trans‐kingdom communication between C andida albicans and S treptococcus gordonii

Summary Recent studies have shown that the transcriptional landscape of the pleiomorphic fungus Candida albicans is highly dependent upon growth conditions. Here using a dual RNA ‐seq approach we identified 299 C. albicans and 72 Streptococcus gordonii genes that were either upregulated or downregulated specifically as a result of co‐culturing these human oral cavity microorganisms. Seventy‐five C. albicans genes involved in responses to chemical stimuli, regulation, homeostasis, protein modification and cell cycle were significantly ( P  ≤ 0.05) upregulated, whereas 36 genes mainly involved in transport and translation were downregulated. Upregulation of filamentation‐associated TEC 1 and FGR 42 genes, and of ALS 1 adhesin gene, concurred with previous evidence that the C. albicans yeast to hypha transition is promoted by S. gordonii . Increased expression of genes required for arginine biosynthesis in C. albicans was potentially indicative of a novel oxidative stress response. The transcriptional response of S. gordonii to C. albicans was less dramatic, with only eight S. gordonii genes significantly ( P  ≤ 0.05) upregulated at least two‐fold ( glpK , rplO , celB , rplN , rplB , rpsE , ciaR and gat ). The expression patterns suggest that signals from S. gordonii cause a positive filamentation response in C. albicans , whereas S. gordonii appears to be transcriptionally less influenced by C. albicans .