Connecting the multiple dimensions of global soil fungal diversity.

How the multiple facets of soil fungal diversity vary worldwide remains virtually unknown, hindering the management of this essential species-rich group. By sequencing high-resolution DNA markers in over 4000 topsoil samples from natural and human-altered ecosystems across all continents, we illustrate the distributions and drivers of different levels of taxonomic and phylogenetic diversity of fungi and their ecological groups. We show the impact of precipitation and temperature interactions on local fungal species richness (alpha diversity) across different climates. Our findings reveal how temperature drives fungal compositional turnover (beta diversity) and phylogenetic diversity, linking them with regional species richness (gamma diversity). We integrate fungi into the principles of global biodiversity distribution and present detailed maps for biodiversity conservation and modeling of global ecological processes.

Global patterns in endemicity and vulnerability of soil fungi.

Fungi are highly diverse organisms, which provide multiple ecosystem services. However, compared with charismatic animals and plants, the distribution patterns and conservation needs of fungi have been little explored. Here, we examined endemicity patterns, global change vulnerability and conservation priority areas for functional groups of soil fungi based on six global surveys using a high-resolution, long-read metabarcoding approach. We found that the endemicity of all fungi and most functional groups peaks in tropical habitats, including Amazonia, Yucatan, West-Central Africa, Sri Lanka, and New Caledonia, with a negligible island effect compared with plants and animals. We also found that fungi are predominantly vulnerable to drought, heat and land-cover change, particularly in dry tropical regions with high human population density. Fungal conservation areas of highest priority include herbaceous wetlands, tropical forests, and woodlands. We stress that more attention should be focused on the conservation of fungi, especially root symbiotic arbuscular mycorrhizal and ectomycorrhizal fungi in tropical regions as well as unicellular early-diverging groups and macrofungi in general. Given the low overlap between the endemicity of fungi and macroorganisms, but high conservation needs in both groups, detailed analyses on distribution and conservation requirements are warranted for other microorganisms and soil organisms.

Biogeographic history of a large clade of ectomycorrhizal fungi, the Russulaceae, in the Neotropics and adjacent regions.

The biogeography of neotropical fungi remains poorly understood. Here, we reconstruct the origins and diversification of neotropical lineages in one of the largest clades of ectomycorrhizal fungi in the globally widespread family Russulaceae. We inferred a supertree of 3285 operational taxonomic units, representing worldwide internal transcribed spacer sequences. We reconstructed biogeographic history and diversification and identified lineages in the Neotropics and adjacent Patagonia. The ectomycorrhizal Russulaceae have a tropical African origin. The oldest lineages in tropical South America, most with African sister groups, date to the mid-Eocene, possibly coinciding with a boreotropical migration corridor. There were several transatlantic dispersal events from Africa more recently. Andean and Central American lineages mostly have north-temperate origins and are associated with North Andean uplift and the general north-south biotic interchange across the Panama isthmus, respectively. Patagonian lineages have Australasian affinities. Diversification rates in tropical South America and other tropical areas are lower than in temperate areas. Neotropical Russulaceae have multiple biogeographic origins since the mid-Eocene involving dispersal and co-migration. Discontinuous distributions of host plants may explain low diversification rates of tropical lowland ectomycorrhizal fungi. Deeply diverging neotropical fungal lineages need to be better documented.

Looks can be deceiving: the deceptive milkcaps (Lactifluus, Russulaceae) exhibit low morphological variance but harbour high genetic diversity.

The ectomycorrhizal genus Lactifluus is known to contain many species complexes, consisting of morphologically very similar species, which can be considered cryptic or pseudocryptic. In this paper, a thorough molecular study is performed of the clade around Lactifluus deceptivus (originally described by Peck from North America) or the deceptive milkcaps. Even though most collections were identified as L. deceptivus, the clade is shown to contain at least 15 species, distributed across Asia and America, indicating that the L. deceptivus clade represents a species complex. These species are morphologically very similar and are characterized by a tomentose pileus with thin-walled hyphae and a velvety stipe with thick-walled hyphae. An ITS1 sequence was obtained through Illumina sequencing for the lectotype of L. deceptivus, dating from 1885, revealing which clade represents the true L. deceptivus. In addition, it is shown that three other described species also belong to the L. deceptivus clade: L. arcuatus, L. caeruleitinctus and L. mordax, and molecularly confirmed that L. tomentoso-marginatus represents a synonym of L. deceptivus. Furthermore, two new Neotropical species are described: Lactifluus hallingii and L. domingensis.

Novel diversity in Lactifluus section Gerardii from Asia: five new species with pleurotoid or small agaricoid basidiocarps.

The ectomycorrhizal milkcap genus Lactifluus (Russulaceae) is commonly found in tropical and subtropical forests of Southeast Asia. During several sampling expeditions in Thailand, multiple collections of Lactifluus (Lf.) species with pleurotoid or small agaricoid basidiocarps were found. A molecular study was combined with a morphological study, in which the collections were compared with herbarium material. The molecular study indicated that four Thai collections belonged to undescribed species within Lactifluus section Gerardii, as was also the case for herbarium collections of a pleurotoid species from Nepal. One other collection from Thailand appeared closely related to Lf. uyedae, known only from Japan. Five species are described as new in the genus: Lf. auriculiformis, Lf. gerardiellus, Lf. bhandaryi, Lf. pulchrellus, and Lf. raspei.

Lactarius subgenus Russularia (Basidiomycota, Russulales): novel Asian species, worldwide phylogeny and evolutionary relationships.

Lactarius subg. Russularia is a large group of milkcaps occurring almost worldwide and dominant in many ecosystems. In this study we focus on new diversity, evolutionary relationships, divergence time, and origin of the subgenus. Six conifer symbionts are described as new to science: Lactarius atrii, L. aurantionitidus, L. dombangensis, L. flavigalactus, L. lachungensis, and L. sikkimensis. Species delimitation is assessed based on the concordance between morphological characteristics and an ITS phylogeny. Infrageneric relationships were studied using a phylogeny constructed from concatenated ITS-rpb2 data using Maximum Likelihood and Bayesian inference. Results show that species in this subgenus do not cluster together according to their geographic origin. Intercontinental sister relationships between Europe/Asia/North America are common but actual conspecificity is rare. This result suggests that allopatric speciation has played an important role within this subgenus. Only few morphological characteristics tend to be phylogenetically informative, with the most important being presence or absence of true cystidia and the pileipellis structure. Two datasets were generated in order to estimate the age of L. subg. Russularia. The results suggest the origin of L. subg. Russularia to be in the Mid Miocene period.

Diversity of Edible and Medicinal Mushrooms Used in the Noun Division of the West Region of Cameroon.

This article presents discussions of mushrooms as a source of food, income, as well as medicine among the Bamoun people of the highlands of West Cameroon, where the vegetation is mainly savannah mixed with forest galleries. Like most tribes in tropical Africa, the Bamoun people use a wide range of natural products as mushrooms. This study attempts to identify the various mushrooms exploited by the Bamoun. Ethnomycological surveys and field trips were conducted over 4 years in several villages in the Noun Division. Samples of wild mushrooms were collected from both the savannah and the forest galleries. These were described, preserved, and identified. The study shows that the Bamoun people use at least 40 species of mushrooms for either food or medicine. These species belong to 8 genera: Auricularia, Cantharellus, Ganoderma, Pleurotus, Lactarius, Lactifluus, Russula, and Termitomyces. Species of genera Lactarius, Lactifluus, Russula, and Termitomyces are most often used for food, whereas Ganoderma spp. and Pleurotus tuber-regium are mainly exploited for medicinal purposes. This survey provides an overview of the diversity of mushrooms and their importance to the local people of this area. Since some of the species mentioned by the local population were not fruiting at the time of our field trips, additional investigations are needed to further clarify the diversity and the usage of mushrooms in this region.

Lactifluus volemus in Europe: Three species in one--Revealed by a multilocus genealogical approach, Bayesian species delimitation and morphology.

This study provides morphological and molecular evidence (from nuclear ITS, LSU, and rpb2 DNA sequences) for three previously unrecognized species within the morphospecies Lactifluus volemus from Europe. Phylogenetic species are supported by both a multi-locus tree-based method and Bayesian species delimitation. Lactifluus volemus and Lactifluus oedematopus are provided with a new description, and a third species, Lactifluus subvolemus, is described as new to science. Lactifluus oedematopus can be easily recognized by its short pileipellis hairs. Both L. volemus and L. subvolemus have longer pileipellis hairs and can only be distinguished from each other based on cap colour. Intermediary colour forms, however, occur as well, and cannot be identified as either L. volemus or L. subvolemus without molecular data. Revealing that L. volemus--already considered extinct in the Netherlands and the Belgian Flemish region, and declining in other European countries--is actually a complex of three species that are even more vulnerable to extinction, this study emphasizes the fundamental role of taxonomy in species conservation.

Importance of autonomous selfing is inversely related to population size and pollinator availability in a monocarpic plant.

PREMISE OF THE STUDY: In animal-pollinated plants, autonomous selfing may provide reproductive assurance when pollinators or reproductive partners are limited. Under such circumstances, the contribution of pollinator-mediated seed set to total seed production also may be more variable compared with situations in which pollinator abundances are high or populations consist of large numbers of individuals. Despite the widespread acceptance of the reproductive assurance hypothesis, only limited empirical evidence exists that autonomous selfing confers reproductive output and guarantees constant seed set under variable pollination environments. METHODS: We performed emasculation experiments in 22 populations of the short-lived, monocarpic plant Centaurium erythraea in a fragmented dune landscape. KEY RESULTS: Floral emasculations resulted in a significantly lower seed set compared with that of intact flowers. Seed set in emasculated flowers also declined significantly with decreasing population size and pollinator availability, whereas seed set of intact flowers did not depend on population size nor on pollinator availability. Variability in seed set among individuals was significantly lower in intact than in emasculated flowers and decreased significantly with increasing population size when flowers were emasculated but not in intact flowers. CONCLUSIONS: These results indicate that pollinator-mediated seed set is strongly dependent both on population size and on pollinator availability but that reproductive assurance through autonomous selfing guarantees relatively constant levels of total seed production, even when populations are small and/or pollinator limited. High variation in seed set of emasculated flowers suggests strong unpredictability in pollinator services in small populations.