FLO8 deletion leads to decreased adhesion and virulence with downregulated expression of EPA1, EPA6, and EPA7 in Candida glabrata.

Background: The Candida glabrata does not develop into a pathogenic hiphal form; however, it has become the second most common pathogen of fungal infections in humans, partly because of its adhesion ability and virulence.

Objectives: The present study aimed to determine whether Flo8, a transcription factor that plays an important role in the virulence and drug resistance in Candida albicans, has a similar role in C. glabrata.

Methods: We constructed FLO8 null strains of a C. glabrata standard strain and eight clinical strains from different sources, and a FLO8 complemented strain. Real-time quantitative PCR, biofilm formation assays, hydrophobicity tests, adhesion tests, Caenorhabditis elegans survival assay, and drug-susceptibility were then performed.

Results: Compared with the wild-type strains, the biofilm formation, hydrophobicity, adhesion, and virulence of the FLO8-deficient strains decreased, accompanied by decreased expression of EPA1, EPA6, and EPA7. On the other hand, it showed no changes in antifungal drug resistance, although the expression levels of CDR1, CDR2, and SNQ2 increased after FLO8 deletion.

Conclusions: These results indicated that Flo8 is involved in the adhesion and virulence of C. glabrata, with FLO8 deletion leading to decreased expression of EPA1, EPA6, and EPA7 and decreased biofilm formation, hydrophobicity, adhesion, and virulence.