Ave Suija

Towards a unified paradigm for sequence‐based identification of fungi

The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for the exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference data set and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here, we report on progress in these regards through further development of the UNITE database (http://unite.ut.ee) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g. Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third‐party annotation effort. We introduce the term ‘species hypothesis’ (SH) for the taxa discovered in clustering on different similarity thresholds (97–99%). An automatically or manually designated sequence is chosen to represent each such SH. These reference sequences are released (http://unite.ut.ee/repository.php) for use by the scientific community in, for example, local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new Web‐based sequence management system in UNITE.

Global diversity and geography of soil fungi

Introduction The kingdom Fungi is one of the most diverse groups of organisms on Earth, and they are integral ecosystem agents that govern soil carbon cycling, plant nutrition, and pathology. Fungi are widely distributed in all terrestrial ecosystems, but the distribution of species, phyla, and functional groups has been poorly documented. On the basis of 365 global soil samples from natural ecosystems, we determined the main drivers and biogeographic patterns of fungal diversity and community composition. Direct and indirect effects of climatic and edaphic variables on plant and fungal richness. Line thickness corresponds to the relative strength of the relationships between the variables that affect species richness. Dashed lines indicate negative relationships. MAP, mean annual precipitation; Fire, time since last fire; Dist. equator, distance from the equator; Ca, soil calcium concentration; P, soil phosphorus concentration; pH, soil pH. Rationale We identified soil-inhabiting fungi using 454 Life Sciences (Branford, CN) pyrosequencing and through comparison against taxonomically and functionally annotated sequence databases. Multiple regression models were used to disentangle the roles of climatic, spatial, edaphic, and floristic parameters on fungal diversity and community composition. Structural equation models were used to determine the direct and indirect effects of climate on fungal diversity, soil chemistry, and vegetation. We also examined whether fungal biogeographic patterns matched paradigms derived from plants and animals—namely, that species’ latitudinal ranges increase toward the poles (Rapoport’s rule) and diversity increases toward the equator. Last, we sought group-specific global biogeographic links among major biogeographic regions and biomes using a network approach and area-based clustering. Results Metabarcoding analysis of global soils revealed fungal richness estimates approaching the number of species recorded to date. Distance from equator and mean annual precipitation had the strongest effects on richness of fungi, including most fungal taxonomic and functional groups. Diversity of most fungal groups peaked in tropical ecosystems, but ectomycorrhizal fungi and several fungal classes were most diverse in temperate or boreal ecosystems, and many fungal groups exhibited distinct preferences for specific edaphic conditions (such as pH, calcium, or phosphorus). Consistent with Rapoport’s rule, the geographic range of fungal taxa increased toward the poles. Fungal endemicity was particularly strong in tropical regions, but multiple fungal taxa had cosmopolitan distribution. Conclusions Climatic factors, followed by edaphic and spatial patterning, are the best predictors of soil fungal richness and community composition at the global scale. Richness of all fungi and functional groups is causally unrelated to plant diversity, with the exception of ectomycorrhizal root symbionts, suggesting that plant-soil feedbacks do not influence the diversity of soil fungi at the global scale. The plant-to-fungi richness ratio declined exponentially toward the poles, indicating that current predictions—assuming globally constant ratios—overestimate fungal richness by 1.5- to 2.5-fold. Fungi follow similar biogeographic patterns as plants and animals, with the exception of several major taxonomic and functional groups that run counter to overall patterns. Strong biogeographic links among distant continents reflect relatively efficient long-distance dispersal compared with macro-organisms. Fungi play major roles in ecosystem processes, but the determinants of fungal diversity and biogeographic patterns remain poorly understood. Using DNA metabarcoding data from hundreds of globally distributed soil samples, we demonstrate that fungal richness is decoupled from plant diversity. The plant-to-fungus richness ratio declines exponentially toward the poles. Climatic factors, followed by edaphic and spatial variables, constitute the best predictors of fungal richness and community composition at the global scale. Fungi show similar latitudinal diversity gradients to other organisms, with several notable exceptions. These findings advance our understanding of global fungal diversity patterns and permit integration of fungi into a general macroecological framework. Global metagenomics detects hotspots of fungal diversity and macroecological patterns and indicates that plant and fungal diversity are uncoupled. [Also see Perspective by Wardle and Lindahl] Assessing fungal diversity worldwide Fungi are hyperdiverse but poorly known, despite their ecological and economic impacts. Tedersoo et al. collected nearly 15,000 topsoil samples from 365 sites worldwide and sequenced their genomes (see the Perspective by Wardle and Lindahl). Overall, they found a striking decline in fungal species richness with distance from the equator. For some specialist groups though, diversity depended more on the abundance of host plants than host diversity or geography. The findings reveal a huge gap between known and described species and the actual numbers of distinct fungi in the worlds soils. Science, this issue 10.1126/science.1256688; see also p. 1052

Tree and stand level variables influencing diversity of lichens on temperate broad-leaved trees in boreo-nemoral floodplain forests

Tree and stand level variables affecting the species richness, cover and composition of epiphytic lichens on temperate broad-leaved trees (Fraxinus excelsior, Quercus robur, Tilia cordata, Ulmus glabra, and U.xa0laevis) were analysed in floodplain forest stands in Estonia. The effect of tree species, substrate characteristics, and stand and regional variables were tested by partial canonical correspondence analysis (pCCA) and by general linear mixed models (GLMM). The most pronounced factors affecting the species richness, cover and composition of epiphytic lichens are acidity of tree bark, bryophyte cover and circumference of tree stems. Stand level characteristics have less effects on the species richness of epiphytic lichens, however, lichen cover and composition was influenced by stand age and light availability. The boreo-nemoral floodplain forests represent valuable habitats for epiphytic lichens. As substrate-related factors influence the species diversity of lichens on temperate broad-leaved trees differently, it is important to consider the effect of each tree species in biodiversity and conservation studies of lichens.

Notes for genera: Ascomycota

Knowledge of the relationships and thus the classification of fungi, has developed rapidly with increasingly widespread use of molecular techniques, over the past 10–15xa0years, and continues to accelerate. Several genera have been found to be polyphyletic, and their generic concepts have subsequently been emended. New names have thus been introduced for species which are phylogenetically distinct from the type species of particular genera. The ending of the separate naming of morphs of the same species in 2011, has also caused changes in fungal generic names. In order to facilitate access to all important changes, it was desirable to compile these in a single document. The present article provides a list of generic names of Ascomycota (approximately 6500 accepted names published to the end of 2016), including those which are lichen-forming. Notes and summaries of the changes since the last edition of ‘Ainsworth & Bisby’s Dictionary of the Fungi’ in 2008 are provided. The notes include the number of accepted species, classification, type species (with location of the type material), culture availability, life-styles, distribution, and selected publications that have appeared since 2008. This work is intended to provide the foundation for updating the ascomycete component of the “Without prejudice list of generic names of Fungi” published in 2013, which will be developed into a list of protected generic names. This will be subjected to the XIXth International Botanical Congress in Shenzhen in July 2017 agreeing to a modification in the rules relating to protected lists, and scrutiny by procedures determined by the Nomenclature Committee for Fungi (NCF). The previously invalidly published generic names Barriopsis, Collophora (as Collophorina), Cryomyces, Dematiopleospora, Heterospora (as Heterosporicola), Lithophila, Palmomyces (as Palmaria) and Saxomyces are validated, as are two previously invalid family names, Bartaliniaceae and Wiesneriomycetaceae. Four species of Lalaria, which were invalidly published are transferred to Taphrina and validated as new combinations. Catenomycopsis Tibell & Constant. is reduced under Chaenothecopsis Vain., while Dichomera Cooke is reduced under Botryosphaeria Ces. & De Not. (Art. 59).

Biogeographical determinants of lichen species diversity on islets in the West‐Estonian Archipelago

Abstract Questions: Do islet area, number of biotopes and distance from the mainland shape lichen species richness on islets? Are there any species- or substrate group-specific trends associated with these factors? Location: Islets of the west Estonian Archipelago, Estonia. Methods: A species list was compiled for each of the 32 islets and the relative abundance of each species was estimated. The lichens were divided into seven groups according to their substrate preferences. Generalized linear model (GLIM) analysis was applied to test the effect of the islet traits on the number of lichen species on the islets and in the substrate groups. The probability of presence/absence and abundance of the most frequent species according to the islet traits were tested with GLIM and general linear mixed model. Results: The lichen flora of the islets consisted of 326 taxa, the number of lichen species per islet varied from 2 to 197. Total number of species per islet and within the substrate groups was positively correlated with islet area and with number of biotopes, and negatively correlated with distance from the mainland; however, these relationships varied among the substrate groups. Although individual lichen species showed variation in responses, general trends in island biogeography were evident. Conclusions: The distribution pattern of lichens on the studied islets follows the theory of island biogeography: the number of species per islet depends on isolation, area and biotope diversity. Species specific traits, such as dispersal strategy and growth form, as well as availability of a particular substrate are important for formation of the lichen flora on islets. Nomenclature: Randlane & Saag (1999, 2004) and Santesson et al. (2004) for lichens; Leht, M. (ed.) 1999 for vascular plants. Abbreviations: AIC = Akaikes information criterion; GLIM = Generalized linear model; TLC = Thin layer chromatography.

Multiple origin of the lichenicolous life habit in Helotiales, based on nuclear ribosomal sequences

The Helotiales are an ecologically and morphologically highly diverse group of ascomycetes that also includes lichen-inhabiting (lichenicolous) species. We generated sequence data of three rDNA regions (nuSSU, nuLSU, 5.8S of ITS) from 28 lichenicolous specimens representing nine genera in order to determine their phylogenetic placement. Based on the most complete dataset of helotialean fungi to date, the analyses were performed using Maximum Likelihood (ML) and Bayesian approaches. Our results suggest that 1) the lichen-inhabiting life-style in Helotiales was subjected to gains or losses at least three times; 2) Thamnogalla, previously tentatively included in Ostropales, is shown to belong to Helotiales; 3) ascomata found intermixed with pycnidia of the asexual Diplolaeviopsis ranula and possessing the same pigments are tentatively considered as the sexual morph of this taxon, and are shown to belong to Helotiales; 4) the lichenicolous species of cf. Diplolaeviopsis, Llimoniella, Rhymbocarpus, Skyttea, Thamnogalla and Unguiculariopsis form a well-supported clade together with non-lichenicolous encoelioid fungi from the genera Ionomidotis, Cordierites and Encoelia; 5) Geltingia associata forms a highly supported clade with the fungicolous asexual fungus Eleutheromyces subulatus, whereas Pezizella epithallina clusters with an aquatic asexual fungus Tetracladium sp.; 6) Phaeopyxis punctum belongs to Ostropomycetidae (Lecanoromycetes), but its deep relationships to other groups remain unresolved based on rDNA sequences.

Lichenicolous fungi of the genus Abrothallus (Dothideomycetes: Abrothallales ordo nov.) are sister to the predominantly aquatic Janhulales

This study provides new insights on the phylogenetic position of the lichenicolous fungal genus Abrothallus based on six molecular markers (nuSSU, nuLSU, mtSSU, RPB1, RPB2 and TEF-α). In a broad-scale analysis, we detected high support for inclusion of the genus within Dothideomycetes. A further analysis provided support for Abrothallus as a member of the subclass Pleosporomycetidae as a sister group of Jahnulales, an order of aquatic Dothideomycetes. Given the exclusive characters of this group of apotheciate fungi within the Dothidiomycetes, a new monotypic order Abrothallales is here introduced together with the new family Abrothallaceae. In a multi-locus analysis (based on the six loci indicated above plus ITS) restricted to 12 putative Abrothallus species, two clearly separated clades were observed: one comprising species growing on lichens of the families Parmeliaceae and Ramalinaceae, and the second including species that live on lichens of the order Peltigerales and the family Cladoniaceae.

The conservation of ground layer lichen communities in alvar grasslands and the relevance of substitution habitats

Semi-natural calcareous grasslands (alvars) are biodiversity hotspots in Northern Europe, particularly for herb layer plants. In the last century, traditional management has ceased, and the area of grasslands has declined due to extensive encroachment. We were interested in the drivers of ground layer (alias terricolous or epigeic) lichen communities. Our survey consisted of 86 habitat fragments in western Estonia, covering four types of historic alvar grasslands and three types of alvar-like habitats. We found that the ground lichen communities were primarily soil-type-specific, but were also affected by historic disturbances and land use change. In contrast to knowledge about herb layer communities, for which shrub encroachment has been shown to be main driver, the increased density of the herb layer and the reduced diversity of microhabitats were major drivers for the ground layer lichen community. These drivers caused a decrease in species richness, but only within the species of conservation value, and also led to a shift in the composition of lichen growth form from the dominance of squamulose and crustose towards fruticose lichens. We conclude that the traditional practice of restoring alvars by cutting shrubs is insufficient to maintain ground layer lichen biodiversity. Alvar maintenance practices should include grazing, which creates various small-scale ground disturbances and increases microhabitat heterogeneity. Alvar-like habitats originating from large-scale historic disturbances appeared to be suitable for calcicolous epigeic lichens, and can therefore be considered to be temporary substitution habitats, i.e. refugia for the regional species pool.

Lichens, Lichenicolous and Allied Fungi Found in Asveja Regional Park (Lithuania)

Abstract Motiejūnaitė J., Berglund T., Czarnota P., Himelbrant D., Högnabba F., Konoreva L. A., Korchikov E. S., Kubiak D., Kukwa M., Kuznetsova E., Leppik E., Lõhmus P., Prigodina Lukošienė I., Pykälä J., Stončius D., Stepanchikova I., Suija A., Thell A., Tsurykau A., Westberg M., 2012: Lichens, lichenicolous and allied fungi found in Asveja Regional Park (Lithuania) [Kerpės, lichenofiliniai ir kerpėms artimi saprotrofiniai grybai Asvejos regioniniame parke]. - Bot. Lith., 18(2): 85-100. The paper reports the results of lichenological investigations in Asveja Regional Park (eastern Lithuania). A large part of the study was performed during the joint 18th Symposium of the Baltic Mycologists and Lichenologists (BMLS) and Nordic Lichen Society (Nordisk Lichenologisk Förening, NLF) meeting on 19-23 September 2011. A list of 259 species is presented. Of these, 30 species are new to Lithuania. Arthonia helvola, Bacidina sulphurella, Candelariella lutella, Catillaria croatica, Cladonia conista, Gyalecta derivata, Lecanoraquercicola, Leptosphaeria ramalinae, Strigula jamesii, Trichonectria rubefaciens, Verrucaria banatica, V. boblensis, V. christiansenii, V. illinoisensis, V. inornata, V. nigrofusca, V. trabicola, Zwackhiomyces diederichii were recorded for the first time in the Baltic countries. New lichens to Lithuania are as follows: Bacidiaincompta, Caloplaca crenulatella, C. pyracea, Catinaria atropurpurea, Lecanora populicola, L. semipallida, Mycobilimbia epixanthoides, Ramalina dilacerata, Verrucaria inaspecta, and new lichenicolous fungi are: Cladosporium licheniphilum, Stigmidium microspilum, Xenonectriella leptalea. Eighteen species included in the Lithuanian Red Data Book were recorded, which is the highest number known for any studied area in Lithuania.

Buelliella lecanorae , a new lichenicolous fungus

A new lichenicolous fungus Buelliella lecanorae Suija & Alstrup, found on epiphytic Lecanora , is described from Estonia.