Genetic Tools in the Nakaseomyces clade for Evolutionary Comparisons of Signal Transduction Pathways.

The genus Nakaseomyces provides four species that are closely related but have different characteristics. For example, N. glabratus (formerly known as Candida glabrata) is a common human pathogen, whereas N. bracarensis and N. nivariensis have been isolated in clinical settings but are not common human pathogens. N. delphensis was isolated from fruit and there is no evidence it is pathogenic. Given the differences, we developed the clade as a molecular genetic system where we could introduce plasmids and assess transcriptional output from cloned promoters. We engineered a CRISPR/Cas9 plasmid that allows for rapid Gibson cloning of gRNAs, generated auxotrophic strains for amino acids and nucleotides, and introduced plasmids into each species. We used promoter-YFP plasmids to determine that while there are differences between the species, each species likely has intact thiamine and phosphate (THI and PHO) signal transduction pathways, and that gene expression in N. glabratus and N. bracarensis is more similar to one another than to the other two species. Finally, we determine that N. glabratus, N. bracarensis, and N. nivariensis persist in a murine macrophage for 24 h, whereas N. delphensis does not. This work describes new molecular tools for genetic manipulation in the Nakaseomyces clade and allows for evolutionary questions to be explored.