Multilocus DNA sequencing of the whiskey fungus reveals a continental-scale speciation pattern.

Baudoinia was described to accommodate a single species, B. compniacensis. Known as the 'whiskey fungus', this species is the predominant member of a ubiquitous microbial community known colloquially as 'warehouse staining' that develops on outdoor surfaces subject to periodic exposure to ethanolic vapours near distilleries and bakeries. Here we examine 19 strains recovered from environmental samples near industrial settings in North America, South America, the Caribbean, Europe and the Far East. Molecular phylogenetic analysis of a portion of the nucLSU rRNA gene confirms that Baudoinia is a monophyletic lineage within the Teratosphaeriaceae (Capnodiales). Multilocus phylogenetic analysis of nucITS rRNA (ITS1-5.8S-ITS2) and partial nucLSU rRNA, beta-tubulin (TUB) and elongation factor 1-alpha (TEF1) gene sequences further indicates that Baudoinia consists of five strongly supported, geographically patterned lineages representing four new species (viz. Baudoinia antilliensis, B. caledoniensis, B. orientalis and B. panamericana).

A rock-inhabiting ancestor for mutualistic and pathogen-rich fungal lineages.

Rock surfaces are unique terrestrial habitats in which rapid changes in the intensity of radiation, temperature, water supply and nutrient availability challenge the survival of microbes. A specialised, but diverse group of free-living, melanised fungi are amongst the persistent settlers of bare rocks. Multigene phylogenetic analyses were used to study relationships of ascomycetes from a variety of substrates, with a dataset including a broad sampling of rock dwellers from different geographical locations. Rock-inhabiting fungi appear particularly diverse in the early diverging lineages of the orders Chaetothyriales and Verrucariales. Although these orders share a most recent common ancestor, their lifestyles are strikingly different. Verrucariales are mostly lichen-forming fungi, while Chaetothyriales, by contrast, are best known as opportunistic pathogens of vertebrates (e.g. Cladophialophora bantiana and Exophiala dermatitidis, both agents of fatal brain infections) and saprophytes. The rock-dwelling habit is shown here to be key to the evolution of these two ecologically disparate orders. The most recent common ancestor of Verrucariales and Chaetothyriales is reconstructed as a non-lichenised rock-inhabitant. Ancestral state reconstructions suggest Verrucariales as one of the independent ascomycetes group where lichenisation has evolved on a hostile rock surface that might have favored this shift to a symbiotic lifestyle. Rock-inhabiting fungi are also ancestral to opportunistic pathogens, as they are found in the early diverging lineages of Chaetothyriales. In Chaetothyriales and Verrucariales, specific morphological and physiological traits (here referred to as extremotolerance) evolved in response to stresses in extreme conditions prevailing on rock surfaces. These factors facilitated colonisation of various substrates including the brains of vertebrates by opportunistic fungal pathogens, as well as helped establishment of a stable lichen symbiosis.

Determination of keratin degradation by fungi using keratin azure.

Azure dye-impregnated sheep's wool keratin (keratin azure) was incorporated in a high pH medium and overlaid on a keratin-free basal medium. The release and diffusion of the azure dye into the lower layer indicated production of keratinase. Fifty-eight fungal taxa, including 49 members of the Arthrodermataceae, Gymnoascaceae and Onygenaceae (Order Onygenales), were assessed for keratin degradation using this method. The results were comparable to measures of keratin utilization reported in studies using tests based on the perforation or erosion of human hair in vitro.

Molecular phylogeny and taxonomy of medically important fungi.

Some recent advances in study of molecular evolution and taxonomy of human pathogens are discussed. In systemic Onygenales as well as in Chaetothyriales, pathogenic species are phylogenetically intermingled with non-pathogenic taxa. When a teleomorph of Coccidioides immitis is eventually found, it is predicted to resemble Uncinocarpus, a genus otherwise comprising environmental species. In the dermatophytes, Trichophyton and Microsporum are paraphyletic, whereas Epidermophyton is polyphyletic. On the basis of 18S and ITS rDNA sequencing data, Exophiala anamorphs (black yeasts) are confirmed to be closely related to the ascomycete genus Capronia. The related neurotropic species Cladophialophora bantiana is remarkable in consistently having introns in its 18S rDNA gene.

Fruiting studies in species of Capronia (Herpotrichiellaceae).

A recently described protocol for the in vitro production of ascomata was employed to determine the sexual incompatibility systems of five species of Capronia. The formation of mature ascomata in isolates derived from single ascospores demonstrated that C. epimyces, C. mansonii, and C. munkii n. sp. are homothallic. In contrast, fertile ascomata were observed only in mass-ascospore isolates and pairwise crosses between specific single-ascospore isolates in C. dactylotricha n. sp. and C. moravica. The Exophiala anamorphs of C. dactylotricha and C. munkii are described and a Phialophora-like synanamorph is reported for the former species. Germinating ascospores of C. munkii formed conidiogenous cells directly, while the ascospores of the remaining species germinated to produce germ tubes and hyphae. The application of the terms 'microcyclic conidiation' to secondary conidium production and 'sclerotial body' and 'stroma' to the multicellular structures produced by species of Capronia and Exophiala are discussed.

Nutritional physiology of type isolates of currently accepted species of Exophiala and Phaeococcomyces.

Nutritional physiological and tolerance tests were performed for all type strains of species currently classified in the black yeast genera Exophiala and Phaeococcomyces, including some additional type strains of taxa recently reidentified as Exophiala species. Most described Exophiala species can be distinguished by physiological characters. Exophiala jeanselmei with its varieties, and E. castellanii should all be retained as separate taxa. The pairs of strains Mycotorula schawii/Exophiala dermatitidis, Hormodendrum negronii/Exophiala jeanselmei var. lecaniicorni and Sporotrichum gougerotii/Torulabergeri were found to be conspecific. Phenetic analyses of physiological data support the identity of Phaeococcomyces exophialae as a yeast-like synanamorph of Exophiala spinifera. The taxonomic positions of the genera Nadsoniella, Phaeoannellomyces and Wangiella are discussed. The genera Exophiala and Phaeococcomyces are unrelated.