Genomic Insights into Lipid Dependency in Atypical Strains of Malassezia pachydermatis

The yeasts of the genus Malassezia are part of the normal skin microbiota of a wide range of warm-blooded animals including humans. Within this genus, Malassezia pachydermatis is commonly found in the normal skin microbiota of a variety of animal hosts. Malassezia yeasts are considered lipid-dependent due to their inability to synthesize long chain fatty acids de novo. While M. pachydermatis is typically able to grow on Sabouraud's agar (SGA) without lipid supplementation, certain strains display an atypical lipid dependency and are unable to grow on SGA. The aim of this work was to study the genomic differences between atypical M. pachydermatis strains unable to grow on SGA and the reference strain. The genomes of three atypical lipid-dependent M. pachydermatis strains were sequenced using Illumina technology and compared with the reference genome of M. pachydermatis neotype strain CBS 1879. A total of 397 small variants with a high or moderate impact on the protein were observed in genes involved in lipid metabolism. Of those small variants observed we highlight the ones observed in 12 out of the 13 genes encoding secretory lipases and in the CKI1 gene that is unique to M. pachydermatis within the genus. The analysis of those small variations suggested a variation in their ability to adapt to environmental changes and their requirements to grow in different culture media.