New regulators of biofilm development in Candida glabrata.

Biofilm formation plays an important role in fungal pathogenesis. In this work, we used a genetic screen in order to identify and characterize genes involved in the formation of biofilms by the opportunistic fungal pathogen Candida glabrata. We identified the Cst6p transcription factor as a negative regulator of the EPA6 gene that encodes an adhesin central to C. glabrata biofilm formation. Analysis of single and double mutant strains showed that Cst6p acts in a pathway independent of the Yak1/Sir4 pathway also known to regulate expression of EPA6 and consequently biofilm formation. In contrast, we showed that the chromatin remodelling Swi/Snf complex positively regulates biofilm formation in C. glabrata. RT-qPCR experiments demonstrated that EPA6 expression, and thus biofilm formation, depends on the integrity of the Sir complex. Finally, we showed that Swi/Snf-dependent regulation of biofilm formation is adhesin-specific.