A WOPR transcriptional regulatory network controls the virulence of the opportunistic fungal pathogen Nakaseomyces glabratus

The WOPR family of transcription factors regulates morphological transitions and virulence in diverse fungal pathogens, yet their roles in Nakaseomyces glabratus —the second leading cause of candidiasis—remain uncharacterized. Through homology searches, we identified two WOPR domain-containing proteins in N. glabratus : Wor1 (CAGL0L02453g) and Pth2 (CAGL0C03740g), and found both are upregulated during invasive infection. Genetic deletion experiments revealed that Wor1, but not Pth2, is critical for pathogenicity. A wor1 mutant strain showed significantly reduced fungal burden in a murine model of systemic infection and impaired adhesion to human epithelial cells. These virulence defects were not associated with changes in morphology or stress tolerance. RNA-Seq analysis of the wor1 mutant during infection identified 400 downregulated and 175 upregulated genes, indicating that Wor1 functions primarily as a transcriptional activator. Among its targets, Wor1 directly bound the promoters of PDR1 and UPC2A . Functional analysis of these downstream targets showed that Upc2A is critical for virulence and adhesion, while Pdr1 expression levels are also critical for these processes. Additionally, Wor1 regulates cell wall proteins involved in host interactions. In conclusion, our study establishes Wor1 as a pivotal regulator of a transcriptional network governing virulence in N. glabratus , controlling host colonization and adhesion by modulating key downstream transcription factors and cell wall components.

IMPORTANCE

Fungal infections are a growing threat, especially for patients with weakened immune systems. Nakaseomyces glabratus is particularly dangerous because it resists many common antifungal drugs and is increasingly difficult to treat. Despite this, we know relatively little about how this pathogen causes disease. Here, we identify a critical protein, Wor1, that controls the pathogenicity of N. glabratus . When WOR1 is disrupted, the fungus becomes significantly less harmful in animal models and loses much of its ability to adhere to human cells—a crucial first step for infection. Understanding how pathogens activate their disease-causing machinery is essential for finding new drug targets. Because Wor1 and the proteins it controls are specific to fungi and absent in humans, they represent promising candidates for developing therapies that attack the fungus without harming the patient.