Regulatory role of Mss11 in virulence: adhesion and biofilm formation.

Introduction: has emerged as a fungal pathogen with high infection and mortality rates, and its primary virulence factors are related to adhesion and biofilm formation. These virulence factors in are primarily mediated by epithelial adhesins (Epas), most of which are encoded in subtelomeric regions and regulated by subtelomeric silencing mechanisms. The transcription factor Mss11, known for its regulatory role in adhesion, biofilm formation, and filamentous growth in and , has also been implicated in the expression of , suggesting its potential influence on virulence. The present study aims to determine the regulatory role of Mss11 in the virulence of .

Methods: In this work, a null mutant and its complemented strain were constructed from a standard strain. The impact of the transcription factor Mss11 on the virulence of was investigated through a series of phenotypic experiments, including the microbial adhesion to hydrocarbons (MATH) test, adherence assay, biofilm assay, scanning electron microscopy and virulence assay. Furthermore, transcriptome sequencing, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and chromatin immunoprecipitation sequencing (ChIP-seq) were employed to investigate the molecular mechanisms behind the regulation of Mss11.

Results: In , the loss of led to a significant reduction in several virulence factors including cell surface hydrophobicity, epithelial cell adhesion, and biofilm formation. These observations were consistent with the decreased virulence of the mutant observed in the infection model. Further exploration demonstrated that Mss11 modulates virulence by regulating and expression. It binds to the upstream regions of and , as well as the promoter regions of the subtelomeric silencing-related genes , , and , indicating the dual regulatory role of Mss11.

Conclusion: Mss11 plays a crucial role in adhesion and biofilm formation, and thus has a broad influence on virulence. This regulation is achieved by regulating the expression of and through both promoter-specific regulation and subtelomeric silencing.