Defining the Candidozyma auris pan-genome and essentiality

Candidozyma auris is an emerging multi-drug resistant fungal pathogen characterized by high mortality and rapid transmission in healthcare settings, but the genetic drivers of phenotypic variation between strains and the landscape of gene essentiality in this organism remain undercharacterized. Here, we integrate pangenomic analysis with global essentiality screening to establish a foundational understanding of the C. auris genome and identify potential therapeutic targets. We performed pangenome analysis on 695 outbreak strains of C. auris selected to be genetically representative of publicly sequenced genomes. After using BLAST to refine the pangenome, we found that 96.8% of gene families were core, with the remaining high-confidence accessory gene families primarily consisting of gene loss events or clade-specific genes. The high proportion of core genes emphasizes the clonal nature of these outbreak strains, but comparative analysis with the closely related C. haemuli species complex suggested that most of these core genes are functionally dispensible. To examine this hypothesis, we developed a novel insertional mutagenesis approach that leverages the promiscuous integration of linear DNA in the C. auris genome. This global analysis identified 614 high-confidence essential genes. Crucially, nearly one-third of these genes, including the conserved translation initiation factor Sui1, exhibit divergent essentiality patterns compared to the model yeasts Candida albicans and Saccharomyces cerevisiae . These findings highlight organism-specific biology that would be overlooked by orthology alone. By combining pangenomic diversity with functional essentiality, this study provides a comprehensive resource for identifying species-specific determinants of virulence and prioritizing novel targets for antifungal drug development.