Exophiala dermatitidis is a polymorphic black yeast found in various habitats such as soil, leaf litter and man-made environments including sinks, dishwashers and saunas. E. dermatitidis is also an opportunistic pathogen of humans where it can cause phaeohyphomycosis and skin infections. 1,8-DHN melanin found in E. dermatitidis has been shown to provide various functions that range from protection against cellular damage to conversion of visible UV energy into heat. Although the E. dermatitidis genome sequence has revealed the presence of genes responsible for production of melanin via three different pathways, relatively little is known about the relative contribution of these pathways to melanization. The aim of this study was to address this issue by using an unbiased genetic approach to determine which pathways are essential for melanin production. To this end, albino mutants lacking the ability to produce melanin were obtained using UV irradiation. Based on genome re-sequencing and SNVs analysis, all the albino mutants showed variants in the PKS1 gene including mutations ranging from missense base substitutions to frameshifts and short deletions. When grown on different carbon sources, some albino mutants were able to recover melanin production. Ultimately, comparative transcriptomics was used as a tool to examine differentially expressed genes when the various albino mutants were grown on different carbon sources. Transcriptomics analysis allowed us to investigate the expression of alternative genes/pathways that can promote the recovery of melanin production in the conditional albino mutants.National Science Foundation award number 2434259.February 202
