S1.3a Genetics andgenomics of Malassezia species

S1.3 MALASSEZIA: GENETICS, GENOMICS, AND BIOLOGY, SEPTEMBER 21, 2022, 11:00 AM - 12:30 PM: : Malassezia includes yeasts belonging to the subphylum Ustilaginomycotina within the Basidiomycota. Malassezia yeasts are attracting the interest of both basic and applied scientists for their unique biological features, and for their importance in clinical and cosmetic settings. Although Malassezia yeasts are commonly found as commensal on human and animal skin, they are also associated with several skin disorders, such as dandruff/seborrheic dermatitis, atopic eczema, pityriasis versicolor, and folliculitis. More recently, an association of Malassezia with Crohn's disease, pancreatic ductal adenocarcinoma, and psoriasis exacerbation has been reported. To understand the genetic basis of Malassezia commensalism and pathogenicity, the availability of genomic and molecular tools plays a crucial role. Genomics advances in Malassezia reveal karyotype variations and gene turnover events, including genes horizontally transferred from bacteria. Moreover, the increasing availability of transcriptomic data allows us to prioritize studies on novel key genes that potentially characterize the pathophysiology of Malassezia fungi. For gene function studies, protocols for Agrobacterium tumefaciens-mediated transformation were developed and utilized in strategies of random insertional mutagenesis or targeted gene replacement through CRISPR/Cas9. Developed tools can be combined with the use of host-pathogen interaction models, such as the easy-to-use wax moth larvae of Galleria mellonella or the more complex murine skin model, enabling the characterization of both the fungal components that trigger skin damage and inflammation, and the inflammatory and antifungal response of the host to prevent fungal infection through immunological and molecular analyses of experimentally infected tissue.