The U.S. Culture Collection Network Lays the Foundation for Progress in Preservation of Valuable Microbial Resources.

The U.S. Culture Collection Network was formed in 2012 by a group of culture collection scientists and stakeholders in order to continue the progress established previously through efforts of an ad hoc group. The network is supported by a Research Coordination Network grant from the U.S. National Science Foundation (NSF) and has the goals of promoting interaction among collections, encouraging the adoption of best practices, and protecting endangered or orphaned collections. After prior meetings to discuss best practices, shared data, and synergy with genome programs, the network held a meeting at the U.S. Department of Agriculture (USDA)-Agricultural Research Service (ARS) National Center for Genetic Resources Preservation (NCGRP) in Fort Collins, Colorado in October 2015 specifically to discuss collections that are vulnerable because of changes in funding programs, or are at risk of loss because of retirement or lack of funding. The meeting allowed collection curators who had already backed up their resources at the USDA NCGRP to visit the site, and brought collection owners, managers, and stakeholders together. Eight formal collections have established off-site backups with the USDA-ARS, ensuring that key material will be preserved for future research. All of the collections with backup at the NCGRP are public distributing collections including U.S. NSF-supported genetic stock centers, USDA-ARS collections, and university-supported collections. Facing the retirement of several pioneering researchers, the community discussed the value of preserving personal research collections and agreed that a mechanism to preserve these valuable collections was essential to any future national culture collection system. Additional input from curators of plant and animal collections emphasized that collections of every kind face similar challenges in developing long-range plans for sustainability.

Phylogeny of Fomitopsis pinicola: a species complex.

Fungal species with a broad distribution may exhibit considerable genetic variation over their geographic ranges. Variation may develop among populations based on geographic isolation, lack of migration, and genetic drift, though this genetic variation may not always be evident when examining phenotypic characters. Fomitopsis pinicola is an abundant saprotrophic fungus found on decaying logs throughout temperate regions of the Northern Hemisphere. Phylogenetic studies have addressed the relationship of F. pinicola to other wood-rotting fungi, but pan-continental variation within F. pinicola has not been addressed using molecular data. While forms found growing on hardwood and softwood hosts exhibit variation in habit and appearance, it is unknown if these forms are genetically distinct. In this study, we generated DNA sequences of the nuc rDNA internal transcribed spacers (ITS), the TEF1 gene encoding translation elongation factor 1-α, and the RPB2 gene encoding the second largest subunit of RNA polymerase II for collections across all major geographic regions where this fungus occurs, with a primary focus on North America. We used Bayesian and maximum likelihood analyses and evaluated the gene trees within the species tree using coalescent methods to elucidate evolutionarily independent lineages. We find that F. pinicola sensu lato encompasses four well-supported, congruent clades: a European clade, southwestern US clade, and two sympatric northern North American clades. Each clade represents distinct species according to phylogenetic and population-genetic species concepts. Morphological data currently available for F. pinicola do not delimit these species, and three of the species are not specific to either hardwood or softwood trees. Originally described from Europe, F. pinicola appears to be restricted to Eurasia. Based on DNA data obtained from an isotype, one well-defined and widespread clade found only in North America represents the recently described Fomitopsis ochracea The remaining two North American clades represent previously undescribed species.

Phylogeny of Fomitopsis pinicola: a species complex.

Fungal species with a broad distribution may exhibit considerable genetic variation over their geographic ranges. Variation may develop among populations based on geographic isolation, lack of migration, and genetic drift, though this genetic variation may not always be evident when examining phenotypic characters. Fomitopsis pinicola is an abundant saprotrophic fungus found on decaying logs throughout temperate regions of the Northern Hemisphere. Phylogenetic studies have addressed the relationship of F. pinicola to other wood-rotting fungi, but pan-continental variation within F. pinicola has not been addressed using molecular data. While forms found growing on hardwood and softwood hosts exhibit variation in habit and appearance, it is unknown if these forms are genetically distinct. In this study, we generated DNA sequences of the nuc rDNA internal transcribed spacers (ITS), the TEF1 gene encoding translation elongation factor 1-α, and the RPB2 gene encoding the second largest subunit of RNA polymerase II for collections across all major geographic regions where this fungus occurs, with a primary focus on North America. We used Bayesian and maximum likelihood analyses and evaluated the gene trees within the species tree using coalescent methods to elucidate evolutionarily independent lineages. We find that F. pinicola sensu lato encompasses four well-supported, congruent clades: a European clade, southwestern US clade, and two sympatric northern North American clades. Each clade represents distinct species according to phylogenetic and population-genetic species concepts. Morphological data currently available for F. pinicola do not delimit these species, and three of the species are not specific to either hardwood or softwood trees. Originally described from Europe, F. pinicola appears to be restricted to Eurasia. Based on DNA data obtained from an isotype, one well-defined and widespread clade found only in North America represents the recently described Fomitopsis ochracea The remaining two North American clades represent previously undescribed species.

Substantial production of drosophilin A methyl ether (tetrachloro-1,4-dimethoxybenzene) by the lignicolous basidiomycete Phellinus badius in the heartwood of mesquite (Prosopis juliflora) trees.

Toxic organohalogen pollutants produced as by-products of industrial processes, such as chloroform and polychlorinated dibenzo-p-dioxins, also have significant natural sources. A substantial terrestrial source of halogenated organics originates from fungal decay of wood and leaf litter. Here we show that the lignicolous basidiomycete Phellinus badius deposits up to 30,000 mg of the halogenated metabolite drosophilin A methyl ether (DAME, tetrachloro-1,4-dimethoxybenzene) per kilogram of decayed heartwood in the mesquite Prosopis juliflora. DAME occurs as clusters of glassy crystals up to 1 mm long within the decayed heartwood. In addition, the Phellinus badius basidiocarps contain an average of 24,000 mg DAME/kg dried fruiting body, testifying to the significant translocation and accumulation of Cl accompanied by DAME biosynthesis. The high DAME concentrations attest to the substantial Cl content of the heartwood, which averages near 5,000 ppm, with Cl/K near 1:1, consistent with an inorganic chloride precursor. Phellinus badius has a circumglobal distribution in the tropics and subtropics, where it is widely distributed on hardwoods and commonly associated with decay of mesquite. There is the potential for extensive DAME formation within decayed heartwood worldwide given the extensive range of Phellinus badius and its propensity to form DAME within mesquites. Further, DAME production is not limited to Phellinus badius but occurs in a range of lignicolous basidiomycetes, suggesting a significant natural reservoir for this chloroaromatic with potential environmental implications.

DNA-based detection of the fungal pathogen Geomyces destructans in soils from bat hibernacula.

White-nose syndrome (WNS) is an emerging disease causing unprecedented morbidity and mortality among bats in eastern North America. The disease is characterized by cutaneous infection of hibernating bats by the psychrophilic fungus Geomyces destructans. Detection of G. destructans in environments occupied by bats will be critical for WNS surveillance, management and characterization of the fungal lifecycle. We initiated an rRNA gene region-based molecular survey to characterize the distribution of G. destructans in soil samples collected from bat hibernacula in the eastern United States with an existing PCR test. Although this test did not specifically detect G. destructans in soil samples based on a presence/absence metric, it did favor amplification of DNA from putative Geomyces species. Cloning and sequencing of PCR products amplified from 24 soil samples revealed 74 unique sequence variants representing 12 clades. Clones with exact sequence matches to G. destructans were identified in three of 19 soil samples from hibernacula in states where WNS is known to occur. Geomyces destructans was not identified in an additional five samples collected outside the region where WNS has been documented. This study highlights the diversity of putative Geomyces spp. in soil from bat hibernacula and indicates that further research is needed to better define the taxonomy of this genus and to develop enhanced diagnostic tests for rapid and specific detection of G. destructans in environmental samples.

Fomitopsis mounceae and F. schrenkii-two new species from North America in the F. pinicola complex.

Two new species, Fomitopsis mounceae and F. schrenkii (Polyporales, Basidiomycota) in the F. pinicola species complex in North America, are described and illustrated. Previous molecular phylogenetic analyses identified three well-delimited lineages that represent F. mounceae and F. ochracea from Canada, the Appalachian Mountains, and the northern United States and F. schrenkii from western and southwestern regions of the United States. Fomitopsis pinicola sensu stricto is restricted to Eurasia and does not occur in North America. Morphological descriptions of basidiocarps and cultures for F. mounceae, F. schrenkii, and F. ochracea are presented. The three species are readily differentiated by nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) sequence, geographic distribution, and basidiospore size. Polyporus ponderosus H. Schrenk is an earlier illegitimate synonym of F. schrenkii. Both F. mounceae and F. schrenkii have a heterothallic multiallelic incompatibility system.

Consistent trade-offs in fungal trait expression across broad spatial scales.

Fungi are the primary agents of terrestrial decomposition, yet our understanding of fungal biogeography lags far behind that of plants, animals and bacteria. Here, we use a trait-based approach to quantify the niches of 23 species of basidiomycete wood decay fungi from across North America, and explore the linkages among functional trait expression, climate and phylogeny. Our analysis reveals a fundamental trade-off between abiotic stress tolerance and competitive ability, whereby fungi with wide thermal and moisture niches exhibit lower displacement ability. The magnitude of this dominance-tolerance trade-off is partially related to the environmental conditions under which the fungi were collected, with thermal niche traits exhibiting the strongest climate relationships. Nevertheless, moisture and thermal dominance-tolerance patterns exhibited contrasting phylogenetic signals, suggesting that these trends are influenced by a combination of niche sorting along taxonomic lines in tandem with acclimation and adaptation at the level of the individual. Collectively, our work reveals key insight into the life history strategies of saprotrophic fungi, demonstrating consistent trait trade-offs across broad spatial scales.

Diversity begets diversity in competition for space.

Competition can profoundly affect biodiversity patterns by determining whether similar species are likely to coexist. When species compete directly for space, competitive ability differences should theoretically promote trait and phylogenetic clustering, provided that niche differences are otherwise minimal. Yet many sessile communities exhibit high biodiversity despite minimal reliance on niche differentiation. A potential explanation is that intransitive competition ('rock-paper-scissors' competition) not only promotes species richness but also fosters coexistence among highly dissimilar species with different competitive strategies. Here, we test this hypothesis using a combination of empirical and analytical approaches. In an experimental system comprising 37 wood-decay basidiomycete fungi grown in nutrient-rich agar media, pairwise displacement was maximized when species had widely different competitive traits and divergent evolutionary histories. However, when these interactions were embedded in models of species-rich communities, high levels of intransitivity ultimately overwhelmed the pairwise relationships, allowing the weakest and most dissimilar species to survive. In line with theoretical expectations, these multispecies assemblages exhibited reduced functional and phylogenetic diversity, yet the smallest losses were likewise observed in species-rich communities. By demonstrating that species richness can act as a self-reinforcing buffer against competitive exclusion, these results contribute to our understanding of how biodiversity is maintained in natural systems.

The U.S. Culture Collection Network Responding to the Requirements of the Nagoya Protocol on Access and Benefit Sharing.

The U.S. Culture Collection Network held a meeting to share information about how culture collections are responding to the requirements of the recently enacted Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization to the Convention on Biological Diversity (CBD). The meeting included representatives of many culture collections and other biological collections, the U.S. Department of State, U.S. Department of Agriculture, Secretariat of the CBD, interested scientific societies, and collection groups, including Scientific Collections International and the Global Genome Biodiversity Network. The participants learned about the policies of the United States and other countries regarding access to genetic resources, the definition of genetic resources, and the status of historical materials and genetic sequence information. Key topics included what constitutes access and how the CBD Access and Benefit-Sharing Clearing-House can help guide researchers through the process of obtaining Prior Informed Consent on Mutually Agreed Terms. U.S. scientists and their international collaborators are required to follow the regulations of other countries when working with microbes originally isolated outside the United States, and the local regulations required by the Nagoya Protocol vary by the country of origin of the genetic resource. Managers of diverse living collections in the United States described their holdings and their efforts to provide access to genetic resources. This meeting laid the foundation for cooperation in establishing a set of standard operating procedures for U.S. and international culture collections in response to the Nagoya Protocol.