Search

Here we present the results of taxonomic and systematic study of the rare truffle-forming genera Destuntzia and Kjeldsenia. Truffle-forming fungi are difficult to study due to their reduced morphological features and their cryptic, hypogeous fruiting habits. The rare occurrence of Destuntzia and Kjeldsenia further compounds these difficulties due to the lack of adequate material for study. Recent forays in North Carolina and Tennessee recovered new specimens of another rarely collected fungus, Octaviania purpurea. Morphological and phylogenetic analysis revealed that Octaviania purpurea is a member of the genus Destuntzia, and this led us to reevaluate the taxonomic status and systematic relationships of other Destuntzia species. We performed a multilocus phylogenetic analysis of Destuntzia specimens deposited in public fungaria, including all available type material, and environmental sequences from animal scat and soil. Our analyses indicate that Destuntzia is a member of the family Claustulaceae within the order Phallales and is a close relative of Kjeldsenia. Results of our phylogenetic analysis infer that three species originally described in the genus Destuntzia are members of the genus Kjeldsenia. We propose three new combinations in Kjeldsenia to accommodate these species as well as a new combination in Destuntzia to accommodate Octaviania purpurea. We also describe a new genus in Claustulaceae, Hosakaea, to accommodate a closely affiliated species, Octaviania violascens. Finally, we transfer the genus Destunzia into the family Claustulaceae and emend the description of the family. The newly proposed combinations in Destuntzia and Kjeldsenia significantly expand the known geographic ranges of both genera. The data from metabarcode analysis of scat and soil also reveal several additional undescribed species that expand these ranges well beyond those suggested by basidiomata collections. Systematic placement of Destuntzia in the saprotrophic order Phallales suggests that this genus is not ectomycorrhizal, and the ecological implications of this systematic revision are discussed. [ABSTRACT FROM AUTHOR]

Amylascus is a genus of ectomycorrhizal truffles within Pezizaceae that is known from Australia and contains only two described species, A. herbertianus and A. tasmanicus. Species of Amylascus are closely related to truffles (Pachyphlodes, Luteoamylascus) and cup fungi (Plicariella) from the Northern Hemisphere. Here we reevaluate the species diversity of Amylascus and related taxa from southern South America and Australia based on new morphological and molecular data. We identify previously undocumented diversity and morphological variability in ascospore color, ascospore ornamentation, hymenial construction, epithecium structure and the amyloid reaction of the ascus in Melzer's reagent. We redescribe two Amylascus species from Australia and describe seven new Amylascus species, five from South America and two from Australia. This is the first report of Amylascus species from South America. We also describe the new South American genus Nothoamylascus as sister lineage to the Pachyphlodes-Amylascus-Luteoamylascus clade (including Amylascus, Luteoamylascus, Pachyphlodes, and Plicariella). We obtained ITS sequences of mitotic spore mats from Nothoamylascus erubescens gen. & sp. nov. and four of the seven newly described Amylascus species, providing the first evidence of mitotic spore mats in Amylascus. Additional ITS sequences from mitotic spore mats reveal the presence of nine additional undescribed Amylascus and one Nothoamylascus species that do not correspond to any sampled ascomata. We also identify three additional undescribed Amylascus species based on environmental sequences from the feces of two grounddwelling bird species from Chile, Scelorchilus rubecula and Pteroptochos tarnii. Our results indicate that ascomata from Amylascus and Nothoamylascus species are rarely collected, but molecular data from ectomycorrhizal roots and mitotic spore mats indicate that these species are probably common and widespread in southern South America. Finally, we present a time-calibrated phylogeny that is consistent with a late Gondwanan distribution. The time since the most recent common ancestor of: 1) the family Pezizaceae had a mean of 276 Ma (217-337 HPD); 2) the Amylascus-Pachyphlodes-Nothoamylascus-Luteoamylascus clade had a mean of 79 Ma (60-100 HPD); and 3) the Amylascus-Pachyphlodes clade had a mean of 50 Ma (38-62 HPD). The crown age of Pachyphlodes had a mean of 39 Ma (25-42 HPD) and Amylascus had a mean age of 28 Ma (20-37 HPD), falling near the Eocene-Oligocene boundary and the onset of the Antarctic glaciation (c. 35 Ma). [ABSTRACT FROM AUTHOR]

Molecular phylogenetic analyses have addressed the systematic position of several major Northern Hemisphere lineages of Pezizales but the taxa of the Southern Hemisphere remain understudied. This study focuses on the molecular systematics and taxonomy of Southern Hemisphere species currently treated in the genera Underwoodia and Gymnohydnotrya. Species in these genera have been identified as the monophyletic/gymnohydnotrya lineage, but no further research has been conducted to determine the evolutionary origin of this lineage or its relationship with other Pezizales lineages. Here, we present a phylogenetic study of fungal species previously described in Underwoodia and Gymnohydnotrya, with sampling of all but one described species. We revise the taxonomy of this lineage and describe three new species from the Patagonian region of South America. Our results show that none of these Southern Hemisphere species are closely related to Underwoodia columnaris, the type species of the genus Underwoodia. Accordingly, we recognize the genus Geomorium described by Spegazzini in 1922 for G. fuegianum. We propose the new family, Geomoriaceae fam. nov., to accommodate this phylogenetically and morphologically unique Southern Hemisphere lineage. Molecular dating estimated that Geomoriaceae started to diverge from its sister clade Tuberaceae c. 112 MYA, with a crown age for the family in the late Cretaceous (c. 67 MYA). This scenario fits well with a Gondwanan origin of the family before the split of Australia and South America from Antarctica during the Paleocene-Eocene boundary (c. 50 MYA). [ABSTRACT FROM AUTHOR]

Soil depth partitioning is thought to promote the diversity of ectomycorrhizal ( EM) fungal communities, but little is known about whether it is controlled by abiotic or biotic factors., In three bioassay experiments, we tested the role of vertical soil heterogeneity in determining the distributions and competitive outcomes of the EM sister species Rhizopogon vinicolor and Rhizopogon vesiculosus. We planted Pseudotsuga menziesii seedlings into soils that were either a homogenized mix of upper and lower depths or vertically stratified combinations mimicking natural field conditions., We found that both species colonized the upper or lower soil depths in the absence of competition, suggesting that their distributions were not limited by abiotic edaphic factors. In competition within homogeneous soils, R. vesiculosus completely excluded colonization by R. vinicolor, but R. vinicolor was able to persist when soils were stratified. The amount of colonization by R. vinicolor in the stratified soils was also significantly correlated with the number of multilocus genotypes present., Taken together, our findings suggest that the differential vertical distributions of R. vinicolor and R. vesiculosus in natural settings are probably attributable to competition rather than edaphic specialization, but that soil heterogeneity may play a key role in promoting EM fungal diversity. [ABSTRACT FROM AUTHOR]