Evolutionary history of Serpulaceae (Basidiomycota): molecular phylogeny, historical biogeography and evidence for a single transition of nutritional mode

<p>Abstract</p> <p>Background</p> <p>The fungal genus <it>Serpula </it>(Serpulaceae, Boletales) comprises several saprotrophic (brown rot) taxa, including the aggressive house-infecting dry rot fungus <it>Serpula lacrymans</it>. Recent phylogenetic analyses have indicated that the ectomycorrhiza forming genera <it>Austropaxillus </it>and <it>Gymnopaxillus </it>cluster within <it>Serpula</it>. In this study we use DNA sequence data to investigate phylogenetic relationships, historical biogeography of, and nutritional mode transitions in Serpulaceae.</p> <p>Results</p> <p>Our results corroborate that the two ectomycorrhiza-forming genera, <it>Austropaxillus </it>and <it>Gymnopaxillus</it>, form a monophyletic group nested within the saprotrophic genus <it>Serpula</it>, and that the <it>Serpula </it>species <it>S. lacrymans </it>and <it>S. himantioides </it>constitute the sister group to the <it>Austropaxillus</it>-<it>Gymnopaxillus </it>clade. We found that both vicariance (Beringian) and long distance dispersal events are needed to explain the phylogeny and current distributions of taxa within Serpulaceae. Our results also show that the transition from brown rot to mycorrhiza has happened only once in a monophyletic Serpulaceae, probably between 50 and 22 million years before present.</p> <p>Conclusions</p> <p>This study supports the growing understanding that the same geographical barriers that limit plant- and animal dispersal also limit the spread of fungi, as a combination of vicariance and long distance dispersal events are needed to explain the present patterns of distribution in Serpulaceae. Our results verify the transition from brown rot to ECM within Serpulaceae between 50 and 22 MyBP.</p

Spatiotemporal variation of the indoor mycobiome in daycare centers

Background Children spend considerable time in daycare centers in parts of the world and are exposed to the indoor micro- and mycobiomes of these facilities. The level of exposure to microorganisms varies within and between buildings, depending on occupancy, climate, and season. In order to evaluate indoor air quality, and the effect of usage and seasonality, we investigated the spatiotemporal variation in the indoor mycobiomes of two daycare centers. We collected dust samples from different rooms throughout a year and analyzed their mycobiomes using DNA metabarcoding. Results The fungal community composition in rooms with limited occupancy (auxiliary rooms) was similar to the outdoor samples, and clearly different from the rooms with higher occupancy (main rooms). The main rooms had higher abundance of Ascomycota, while the auxiliary rooms contained comparably more Basidiomycota. We observed a strong seasonal pattern in the mycobiome composition, mainly structured by the outdoor climate. Most markedly, basidiomycetes of the orders Agaricales and Polyporales, mainly reflecting typical outdoor fungi, were more abundant during summer and fall. In contrast, ascomycetes of the orders Saccharomycetales and Capnodiales were dominant during winter and spring. Conclusions Our findings provide clear evidences that the indoor mycobiomes in daycare centers are structured by occupancy as well as outdoor seasonality. We conclude that the temporal variability should be accounted for in indoor mycobiome studies and in the evaluation of indoor air quality of buildings. Video abstrac