title: From the Tunnels into the Treetops: New Lineages of Black Yeasts from Biofilm in the Stockholm Metro System and Their Relatives among Ant-Associated Fungi in the Chaetothyriales.
abstract: Rock-inhabiting fungi harbour species-rich, poorly differentiated, extremophilic taxa of polyphyletic origin. Their closest relatives are often well-known species from various biotopes with significant pathogenic potential. Speleothems represent a unique rock-dwelling habitat, whose mycobiota are largely unexplored. Isolation of fungi from speleothem biofilm covering bare granite walls in the Kungsträdgården metro station in Stockholm yielded axenic cultures of two distinct black yeast morphotypes. Phylogenetic analyses of DNA sequences from six nuclear loci, ITS, nuc18S and nuc28S rDNA, rpb1, rpb2 and β-tubulin, support their placement in the Chaetothyriales (Ascomycota). They are described as a new genus Bacillicladium with the type species B. lobatum, and a new species Bradymyces graniticola. Bacillicladium is distantly related to the known five chaetothyrialean families and is unique in the Chaetothyriales by variable morphology showing hyphal, meristematic and yeast-like growth in vitro. The nearest relatives of Bacillicladium are recruited among fungi isolated from cardboard-like construction material produced by arboricolous non-attine ants. Their sister relationship is weakly supported by the Maximum likelihood analysis, but strongly supported by Bayesian inference. The genus Bradymyces is placed amidst members of the Trichomeriaceae and is ecologically undefined; it includes an opportunistic animal pathogen while two other species inhabit rock surfaces. ITS rDNA sequences of three species accepted in Bradymyces and other undescribed species and environmental samples were subjected to phylogenetic analysis and in-depth comparative analysis of ITS1 and ITS2 secondary structures in order to study their intraspecific variability. Compensatory base change criterion in the ITS2 secondary structure supported delimitation of species in Bradymyces, which manifest a limited number of phenotypic features useful for species recognition. The role of fungi in the speleothem biofilm and relationships of Bacillicladium and Bradymyces with other members of the Chaetothyriales are discussed.
authors.affiliation: Department of Taxonomy, Institute of Botany of the Czech Academy of Sciences, 252 43, Průhonice, Czech Republic.
authors.forename: Martina
authors.identifier: http://orcid.org/0000-0001-5229-1709
authors.initials: M
authors.lastname: Réblová
authors.affiliation: Department of Botany, Faculty of Science, Charles University in Prague, 128 01, Prague, 2, Czech Republic.|Laboratory of Fungal Genetics and Metabolism, Institute of Microbiology of the Czech Academy of Sciences, 142 20, Prague, 4, Czech Republic.
authors.forename: Vit
authors.initials: V
authors.lastname: Hubka
authors.affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91, Stockholm, Sweden.
authors.forename: Olle
authors.initials: O
authors.lastname: Thureborn
authors.affiliation: Department of Botany, Swedish Museum of Natural History, 104 05, Stockholm, Sweden.
authors.forename: Johannes
authors.initials: J
authors.lastname: Lundberg
authors.affiliation: Department of Biology, University of Southern Denmark, 5230, Odense, Denmark.|Department of Palaeobiology, Swedish Museum of Natural History, 104 05, Stockholm, Sweden.
authors.forename: Therese
authors.initials: T
authors.lastname: Sallstedt
authors.affiliation: Department of Botany, Swedish Museum of Natural History, 104 05, Stockholm, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Wedin
authors.affiliation: Department of Palaeobiology, Swedish Museum of Natural History, 104 05, Stockholm, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Ivarsson
mesh_terms: D000818:Animals; D001000:Ants / Q000382:microbiology*; D001203:Ascomycota / Q000145:classification / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D001499:Bayes Theorem; D018441:Biofilms; D004271:DNA, Fungal / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D012319:RNA Polymerase II / Q000235:genetics; D016415:Sequence Alignment; D013548:Sweden; D014404:Tubulin / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D005656:Fungal Proteins; D014404:Tubulin; D012319:RNA Polymerase II