André De Kesel

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

Major clades in tropical Agaricus

Agaricus (Basidiomycota) is a genus of saprobic fungi that includes edible cultivated species such as Agaricus bisporus, the button mushroom. There has been considerable ecological, nutritional and medicinal interest in the genus, yet the extent of its diversity remains poorly known, particularly in subtropical and tropical areas. Classification of tropical species has for a large part followed the classification of temperate species. The objective of our study was to examine to what extent this system of classification is appropriate for tropical Agaricus species. Species from temperate sections were therefore compared to the major clades of tropical species using a phylogenetic approach. ITS1 + 2 sequence data from 128 species were used in the phylogenetic analysis. Specimens included four species of genera closely related to Agaricus, 38 temperate species representing the eight classical sections of the genus, and 86 putative species of Agaricus from tropical areas of Africa, Asia and the Americas. Bayesian and maximum likelihood analyses produced relatively congruent trees and almost identical clades. Our data show that (i) only about one-third of tropical species belong to the classical sections based on temperate species; the systematics of the genus therefore needs to be expanded; (ii) among the remaining two-thirds of tropical species, those from the Americas and those from Africa and/or Asia group in distinct clades, suggesting that secondary diversification occurred in these two areas; (iii) in contrast, several clades of classical sections contain American and African + Asian species along with temperate species. In this study, we used approximately 50 distinct species from a small area of northern Thailand, most probably being novel species. This diversity indicates that Agaricus is a species-rich genus in the tropics as well as in temperate regions. The number of species and the hypothetical paleotropical origin of the genus are discussed.

Laboulbenia slackensis and L. littoralis sp. nov. (Ascomycota, Laboulbeniales), two sibling species as a result of ecological speciation

Laboulbenia littoralis is described from the halobiont Cafius xantholoma (Coleoptera, Staphylinidae); it previously was misidentified and not properly documented. Morphologically the new species belongs to a group of carabidicolous taxa similar to Laboulbenia pedicellata and especially Laboulbenia slackensis. It is generally accepted that the specificity of Laboulbeniales is based on their need for substances from the host. In this relatively strict context, shifts between unrelated hosts are difficult to explain. We present morphological and ecological evidence supporting the hypothesis that these fungi are capable of shifting between unrelated hosts as long as they share the same habitat. Adaptation to a particular environment, combined with a reduced dependence from specific nutrients of the host, explains the proposed interfamilial host shift.

Laboulbeniales (Ascomycota) of the Boston Harbor Islands I: species parasitizing Coccinellidae and Staphylinidae, with comments on typification.

Abstract This paper, based on a recent comprehensive sampling of insects, is the first report of Laboulbeniales from the New England region since the 1930s. We present 7 new records of laboulbenialean parasites on Staphylinidae (rove beetles) and Coccinellidae (lady beetles) from the Boston Harbor Islands National Recreation Area. These are Clonophoromyces nipponicus Terada & I.I. Tav., Hesperomyces virescens Thaxt., Ilyomyces cf. mairei F. Picard, Laboulbenia philonthi Thaxt., Peyritschiella protea Thaxt., Stichomyces conosomatis Thaxt., and Teratomyces actobii Thaxt. One of these parasite species, C. nipponicus, has not been found previously outside of its type locality in Japan. Examination of Roland Thaxters 1891–1932 slides led to the designation of lectotypes for L. philonthi, P. protea, S. conosomatis, and T. actobii. The following synonymy is established: Teratomyces brevicaulis Thaxt. = T. actobii. In addition, we discovered new localities for H. virescens (from Canada, Cuba, Guatemala, and Japan) and L. philonthi (from Canada, Grenada, Panama, Trinidad, and Venezuela).

Cantharellus solidus, a New Species from Benin (West-Africa) with a Smooth Hymenium

Abstract This paper presents Cantharellus solidus, a new species from the Guineo-Sudanian part of Benin (West Africa). C. solidus is likely close to the C. lateritius-complex and occurs in forest galleries dominated by Berlinia grandiflora and Uapaca togoensis. Data from specimens collected in Bénin were compiled and compared with data available on a number of closely related taxa. Illustrations of macroscopy and microscopy are given, as well as information on its ecology.

New and Interesting Cantharellus from Tropical Africa

Abstract This paper deals with some of the larger, more or less yellowish or orange Cantharellus species from the tropical African woodlands and rain forests. Four new species with clamp connections are described: Cantharellus guineensis, C. mikemboensis, C. pseudomiomboensis and C. stramineus. The new taxa show moderate to strong resemblance to either Cantharellus rufopunctatus or C. miomboensis. A two-locus phylogeny, based on part of the protein coding genes rpb2 and tef-1, resolved them as a highly supported clade within Cantharellus subgenus Rubrinus, a subgenus still exclusively composed of tropical African species. This monophyletic clade is here described as a new section within subg. Rubrinus. As the subgenus was previously defined as being composed of chanterelles lacking clamp connections, the definition of the subgenus is here amended. Illustrations and new records are also presented for Cantharellus afrocibarius, C. defibulatus, C. miomboensis, C. rufopunctatus and C. sublaevis. This paper provides first sequences for C. defibulatus, C. rufopunctatus and C. sublaevis, all of which are here epitypified, as well as new sequences for more than a dozen other Cantharellus. Cantharellus cibarius var. latifolius is considered a synonym of C. afrocibarius. An identification key to all mainland African Cantharellus is proposed.

The genus Lactarius s. str. (Basidiomycota, Russulales) in Togo (West Africa): phylogeny and a new species described

Lactarius s. str. represents a monophyletic group of about 40 species in tropical Africa, although the delimitation of the genus from Lactifluus is still in progress. Recent molecular phylogenetic and taxonomic revisions have led to numerous changes in names of tropical species formerly referred to Lactarius. To better circumscribe the genus Lactarius in Togo, we combined morphological data with sequence analyses and phylogeny inference of rDNA ITS sequences. Morphological and molecular data were generated from specimens sampled in various native woodlands and riverside forests; Lactarioid- and Russula sequences from public GenBank NCBI, and UNITE are included for phylogenetic analysis. The Maximum likelihood phylogeny tree inferred from aligned sequences supports the phylogenetic position of the studied samples from Togo within the subgenera Piperites, and Plinthogali. Lactarius s. str. includes about 13 species described from West Africa, of which eight were not previously known from Togo, including one new species: Lactarius subbaliophaeus identifiable by the presence of winged basidiospores, a pallisadic pileipellis with a uprapellis composed of cylindrical cells, inconspicuous pleurocystidia, and fusiform or tortuous, often tapering apex marginal cells. It can also be recognised by a transparent white latex that turns pinkish and then blackish, and a bluish reaction of the flesh context with FeSO4. These features mentioned do not match any of the morpho-anatomically most similar species, notably L. baliophaeus and L. griseogalus.

Pulveroboletus fragrans, a new Boletaceae species from Northern Thailand, with a remarkable aromatic odor

Pulveroboletus fragrans, a new bolete species with a strong aromatic odor, was found in forests dominated by Castanopsis and Lithocarpus (Fagaceae) in Northern Thailand. The species is introduced with macroscopic and microscopic descriptions and illustrations, as well as a three-gene phylogenetic analysis that confirms its position within the Pulveroboletus clade of Boletaceae. Pulveroboletus fragrans can be easily distinguished from all other Pulveroboletus species by its strong aromatic odor, the violaceous to purple color of the uppermost part of the stipe, and viscid general veil covering the pileus and stipe. The nature of the general veil is discussed.

New and interesting Laboulbeniales (Fungi, Ascomycota) from the Netherlands

Thirteen species of Laboulbeniales (Fungi, Ascomycota) are reported for the first time from the Netherlands. These are Bordea denotata sp. nov., Botryandromyces heteroceri, Chaetarthriomyces crassappendicatus, Cryptandromyces elegans, Ecteinomyces trichopterophilus, Kainomyces rehmanii, Laboulbenia fennica, L. inflata, L. luxurians, L. philonthi, Monoicomyces britannicus, M. myllaenae, and Siemaszkoa fennica. A new staphylinid host is reported for Monoicomyces, i.e. Acrotona pseudotenera.

Reconciling biodiversity and carbon stock conservation in an Afrotropical forest landscape

Positive relationships between carbon storage and taxonomic diversity are not predominant at the local scale. Protecting aboveground carbon stocks in tropical forests is essential for mitigating global climate change and is assumed to simultaneously conserve biodiversity. Although the relationship between tree diversity and carbon stocks is generally positive, the relationship remains unclear for consumers or decomposers. We assessed this relationship for multiple trophic levels across the tree of life (10 organismal groups, 3 kingdoms) in lowland rainforests of the Congo Basin. Comparisons across regrowth and old-growth forests evinced the expected positive relationship for trees, but not for other organismal groups. Moreover, differences in species composition between forests increased with difference in carbon stock. These variable associations across the tree of life contradict the implicit assumption that maximum co-benefits to biodiversity are associated with conservation of forests with the highest carbon storage. Initiatives targeting climate change mitigation and biodiversity conservation should include both old-growth and regenerating forests to optimally benefit biodiversity and carbon storage.