IMA Fungus 8(2): 299-315, doi: 10.5598/imafungus.2017.08.02.05
A new family and genus in Dothideales for Aureobasidium-like species isolated from house dust
Zoë Humphries‡, Keith A. Seifert‡, Yuuri Hirooka§, Cobus M. Visagie|‡ Agriculture and Agri-Food Canada, Biodiversity (Mycology), Ottawa Research and Development Centre, Ottawa, Canada§ Hosei University, Department of Clinical Plant Science, Faculty of Bioscience, Koganei, Tokyo, Japan| Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Department of Biochemistry, Genetics and Microbiology, Pretoria, South Africa
© Zoë Humphries, Keith Seifert, Yuuri Hirooka, Cobus Visagie. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY-NC 4.0), which permits to copy and distribute the article for non-commercial purposes, provided that the article is not altered or modified and the original author and source are credited. Citation:
Humphries Z, Seifert KA, Hirooka Y, Visagie CM (2017) A new family and genus in Dothideales for Aureobasidium-like species isolated from house dust. IMA Fungus 8(2): 299-315. https://doi.org/10.5598/imafungus.2017.08.02.05 |  |
Abstract
An international survey of house dust collected from eleven countries using a modified dilution-to-extinction method yielded 7904 isolates. Of these, six strains morphologically resembled the asexual morphs of Aureobasidium and Hormonema (sexual morphs ?Sydowia), but were phylogenetically distinct. A 28S rDNA phylogeny resolved strains as a distinct clade in Dothideales with families Aureobasidiaceae and Dothideaceae their closest relatives. Further analyses based on the ITS rDNA region, p-tubulin, 28S rDNA, and RNA polymerase II second largest subunit confirmed the distinct status of this clade and divided strains among two consistent subclades. As a result, we introduce a new genus and two new species as Zalaria alba and Z. obscura, and a new family to accommodate them in Dothideales. Zalaria is a black yeast-like fungus, grows restrictedly and produces conidiogenous cells with holoblastic synchronous or percurrent conidiation. Zalaria microscopically closely resembles Hormonema by having only one to two loci per conidiogenous cell, but species of our new genus generally has more restricted growth. Comparing the two species, Z. obscura grows faster on lower water activity (aw) media and produces much darker colonies than Z. alba after 7 d. Their sexual states, if extant, are unknown.
Keywords
18S, 28S, BenA, black yeast, Dothidiomycetes, ITS, RPB2, xerotolerant fungi, Zalaria