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In the fungal kingdom there is a high prevalence of morphologically defined species that includes closely related 'cryptic' biological species with similar phenotypes. Due to evolutionary processes like incomplete lineage sorting and introgression through hybridization, several independent DNA markers are essential to resolve closely related fungal species. In this study we wanted to analyze how many independent loci are necessary to reveal the cryptic species, using the genus Serpula as a model system. DNA sequences from ten different DNA loci, eight nuclear and two mitochondrial DNA markers, were obtained from various cryptic species within Serpula. The inclusion of five loci gave a highly confident separation of the cryptic species. Several other loci performed better than the standard DNA barcoding marker ITS in separating the cryptic species. The DNA loci tub, hsp, rpb2 and tef gave, on average, best support for the different cryptic species in single gene trees. We conclude that the analyses of a few but informative independent DNA loci, such as tub, hsp, rpb2 and tef in addition to the standard DNA barcode ITS, may give a good indication about the existence of cryptic species in fungi., (Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

Background: The fungal genus Serpula (Serpulaceae, Boletales) comprises several saprotrophic (brown rot) taxa, including the aggressive house-infecting dry rot fungus Serpula lacrymans. Recent phylogenetic analyses have indicated that the ectomycorrhiza forming genera Austropaxillus and Gymnopaxillus cluster within Serpula. In this study we use DNA sequence data to investigate phylogenetic relationships, historical biogeography of, and nutritional mode transitions in Serpulaceae., Results: Our results corroborate that the two ectomycorrhiza-forming genera, Austropaxillus and Gymnopaxillus, form a monophyletic group nested within the saprotrophic genus Serpula, and that the Serpula species S. lacrymans and S. himantioides constitute the sister group to the Austropaxillus-Gymnopaxillus 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., Conclusions: 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.

Serpula himantioides is a widespread saprotrophic morphospecies mainly colonising coniferous wood in nature, but it appears frequently in buildings as well. From an earlier study, it is known that at least three divergent lineages occur within the S. himantioides species complex. In this study, a broader sample of S. himantioides isolates has been analysed by multi-locus sequencing, including new isolates from Asia, North and South America. Altogether five phylogenetical species (PS1-5) were detected, all recognised across independent gene phylogenies. A new southern South American phylogenetic species (PS1) was found, representing an early diverging lineage within the S. himantioides species complex. The two closely related PS2 and PS3 lineages included isolates from North America only, and PS4 was also dominated by North American isolates. Most of the investigated isolates (76%) clustered into PS5, a lineage that has been found on most continents, including North America. Overall, little phylogeographical structure was found in PS5, indicating frequent and recent long-distance dispersal events within this widespread lineage. Our analyses indicate that South and North America are the centres of divergence for the S. himantioides species complex. Some of the lineages seem adapted to various substrates, but PS5 is able to decay a wide array of angiosperms and gymnosperms, which may have facilitated the spread of this lineage throughout the world., (Copyright © 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.)