Chapter 12 397 The Malassezia globosa Genome In order to further our understanding of Malassezia and human scalp biology and their unique lipid dependence, we sequenced the complete genomes of M. globosa and M. restricta.46 The M. globosa genome is 9 Mb, among the smallest of free-living fungi.47-48 To assist in identification of protein open coding frames, we sequenced a cDNA library, resulting in the prediction of 4,289 protein coding genes. Even with this small gene compliment, the genome contains all of the necessary components for glycolysis, the TCA cycle, synthesis of all twenty amino acids and the five nucleic acid bases, among others. The key deficiencies linked to lipid dependence are the absence of a fatty acid synthase and a Δ-9 desaturase. Malassezia seem to have complimented their need for fatty acid assimilation by duplicating a high number of secreted lipases (13) and phospholipases (9). Reverse transcription Polymerase Chain Reaction (RT-PCR) and proteomics experiments from cultured cells and isolated from human scalp confirm the expression of multiple lipase and phospholipase genes. Also, multiple genes for generation of peroxides were identified, making it likely that Malassezia are involved in damage to the hair shaft as well as the scalp. This hypothesis is also supported by recent work indicating that hair sampled from dandruff sufferers was less healthy than that isolated from non-dandruff subjects.49 Of course, these hydrolytic enzymes require extracellular secretion to interact with host skin. We therefore performed proteomics experiments (on cultured cells) to identify over 50 secreted proteins. The most abundant of the identifiable secreted proteins were, as hypothesized, lipases. In addition, many other secreted proteins were identified, including aspartyl proteases, members of the phospholipase C family, glucose-methanol-choline (GMC) oxidoreductases, known Malassezia allergens,50 cell wall modifying enzymes, and unknown proteins. Because these proteins are secreted, they would be the most likely to interact with skin and would therefore mediate Malassezia pathogenicity and be relevant therapeutic targets.