Solving the ecological puzzle of mycorrhizal associations using data from annotated collections and environmental samples - an example of saddle fungi

Phylogeny and species diversity of the genus Helvella with emphasis on eighteen new species from China

Helvella is a widespread, frequently encountered fungal group appearing in forests, but the species diversity and molecular phylogeny of Helvella in China remains incompletely understood. In this work, we performed comprehensive phylogenetic analyses using multilocus sequence data. Six datasets were employed, including a five-locus concatenated dataset (ITS, nrLSU, tef1-α, rpb2, hsp), a two-locus concatenated dataset (ITS, nrLSU), and four single-locus datasets (ITS) that were divided based on the four different phylogenetic clades of Helvella recognized in this study. A total of I 946 sequences were used, of which 713 were newly generated, including 170 sequences of ITS, 174 sequences of nrLSU, 131 sequences of tef1-α, 107 sequences of rpb2 and 131 sequences of hsp. The phylogeny based on the five-locus concatenated dataset revealed that Helvellas. str. is monophyletic and four phylogenetic clades are clearly recognized, i.e., Acetabulum clade, Crispa clade, Elastica clade, and Lacunosa clade. A total of 24 lineages or subclades were recognized, II of which were new, the remaining 13 corresponding with previous studies. Chinese Helvella species are distributed in 22 lineages across four clades. Phylogenetic analyses based on the two-locus concatenated dataset and four single-locus datasets confirmed the presence of at least 93 phylogenetic species in China. Among them, 58 are identified as known species, including a species with a newly designated lectotype and epitype, 18 are newly described in this paper, and the remaining 17 taxa are putatively new to science but remain unnamed due to the paucity or absence of ascomatal materials. In addition, the Helvella species previously recorded in China are discussed. A list of 76 confirmed species, including newly proposed species, is provided. The occurrence of H. crispa and H. elastica are not confirmed although both are commonly recorded in China. Citation: Mao N, Xu YY, Zhang YX, Zhou H, Huang XB, Hou CL, Fan L (2023). Phylogeny and species diversity of the genus Helvella with emphasis on eighteen new species from China. Fungal Systematics and Evolution 12: 111-152. doi: 10.3114/fuse.2023.12.08.

Four new additions to Helvella (Helvellaceae, Pezizales) from Northern Thailand

Most species of Helvella have been described from temperate regions in Asia, Europe, and North America, but little is known about the genus from tropical regions. In this report, phylogenetic analyses of 11 newly collected saddle-like fungi from northern Thailand using three genetic markers [the nuclear large subunit ribosomal DNA (LSU), the heat shock protein 90 (HSP90), and the translation elongation factor 1-alpha (TEF)] confirm their assignment in Helvella. Two species were described as new, i.e., Helvella atroides and H. orentitomentosa, and two species, i.e., H. fistulosa and H. rugosa, were reported for the first time in Thailand. Details of macro- and microscopic characters and illustrations were provided for each species. To date, seven species of Helvella have been recorded in Thailand, and a key for identifying the Thai Helvella species was provided here.

Species Diversity of Helvella lacunosa Clade (Pezizales, Ascomycota) in China and Description of Sixteen New Species

Helvella lacunosa and its allies are widely distributed in the Northern Hemisphere and perform important functions in ecosystems. A comprehensive study on 101 collections of Helvella lacunosa, including those deposited in four Chinese fungaria or collected recently from 10 provinces, was conducted based on morphological and molecular characteristics. Phylogenies of "Helvella lacunosa clade" inferred from Hsp90, ITS, LSU, and TEF were reconstructed with 49 lineages recognized, of which 25 lineages occurred in China, and each represented an individual species. Sixteen new species were determined with detailed descriptions and illustrations. Two new Chinese records were reported. Species concepts and their distinctions in macro- and micro-features were discussed.

Phylogeny and Taxonomic Revision of the Family Discinaceae (Pezizales, Ascomycota)

Species of Discinaceae are common macrofungi with a worldwide distribution. Some of them are commercially consumed, while a few others are reported as poisonous. Two genera were accepted in the family: the epigeous Gyromitra with discoid, cerebriform to saddle-shaped ascomata and the hypogeous Hydnotrya with globose or tuberous ascomata. However, due to discrepancies in their ecological behaviors, a comprehensive investigation of their relationship was not thoroughly explored. In this study, phylogenies of Discinaceae were reconstructed using sequence analyses of combined and separate three gene partitions (internal transcribed spacer [ITS], large subunit ribosomal DNA [LSU], and translation elongation factor [TEF]) with a matrix containing 116 samples. As a result, the taxonomy of the family was renewed. Eight genera were recognized: two of them (Gyromitra and Hydnotrya) were retained, three (Discina, Paradiscina, and Pseudorhizina) were revived, and three (Paragyromitra, Pseudodiscina, and Pseudoverpa) were newly established. Nine new combinations were made in four genera. Two new species in Paragyromitra and Pseudodiscina and an un-named taxon of Discina were described and illustrated in detail based on the materials collected from China. Furthermore, a key to the genera of the family was also provided. IMPORTANCE Taxonomy of the fungal family Discinaceae (Pezizales, Ascomycota) was significantly renewed on the basis of sequence analyses of internal transcribed spacer (ITS), large subunit ribosomal DNA (LSU), and translation elongation factor (TEF). Eight genera were accepted, including three new genera; two new species were described; and nine new combinations were made. A key to the accepted genera of the family is provided. The aim of this study is to deepen the understanding of the phylogenetic relationships among genera of the group, as well as the associated generic concepts.

Additions to the knowledge of the genus Helvella in Europe. New records and de novo description of five species from the Nordic region

Helvella is a species-rich genus, forming a large variation of astounding ascocarps in many different habitats. During the last decade, molecular markers and morphological characters have been combined to delimit and identify cryptic species in this genus. We report on a list of 54 species of Helvella s.s. in the Nordic region and describe five new species, i.e. H. bresadolae, H. convexa, H. japonica, H. nordlandica and H. oroarctica. The morphological and molecular characteristics of the new species and the emended / hypocrateriformis, / fibrosa-macropus, and / fallax-pezizoides lineages of Helvella s.s. are shortly commented upon. Further we include a discussion of the distribution of species in the Nordic region based on a large set of studied collections. The ecological versatility and variable geographic patterns of these species indicate that cryptic species may have contrasting ecology in their local habitats. Citation: Skrede I, Løken SB, Mathiesen C, Schumacher T (2023). Additions to the knowledge of the genus Helvella in Europe. New records and de novo description of five species from the Nordic region. Fungal Systematics and Evolution 11: 71-84. doi: 10.3114/fuse.2023.11.06.

Utility of targeted sequence capture for phylogenomics in rapid, recent angiosperm radiations: Neotropical Burmeistera bellflowers as a case study

Targeted sequence capture is a promising approach for large-scale phylogenomics. However, rapid evolutionary radiations pose significant challenges for phylogenetic inference (e.g. incomplete lineages sorting (ILS), phylogenetic noise), and the ability of targeted nuclear loci to resolve species trees despite such issues remains poorly studied. We test the utility of targeted sequence capture for inferring phylogenetic relationships in rapid, recent angiosperm radiations, focusing on Burmeistera bellflowers (Campanulaceae), which diversified into ~130 species over less than 3 million years. We compared phylogenies estimated from supercontig (exons plus flanking sequences), exon-only, and flanking-only datasets with 506-546 loci (~4.7 million bases) for 46 Burmeistera species/lineages and 10 outgroup taxa. Nuclear loci resolved backbone nodes and many congruent internal relationships with high support in concatenation and coalescent-based species tree analyses, and inferences were largely robust to effects of missing taxa and base composition biases. Nevertheless, species trees were incongruent between datasets, and gene trees exhibited remarkably high levels of conflict (~4-60% congruence, ~40-99% conflict) not simply driven by poor gene tree resolution. Higher gene tree heterogeneity at shorter branches suggests an important role of ILS, as expected for rapid radiations. Phylogenetic informativeness analyses also suggest this incongruence has resulted from low resolving power at short internal branches, consistent with ILS, and homoplasy at deeper nodes, with exons exhibiting much greater risk of incorrect topologies due to homoplasy than other datasets. Our findings suggest that targeted sequence capture is feasible for resolving rapid, recent angiosperm radiations, and that results based on supercontig alignments containing nuclear exons and flanking sequences have higher phylogenetic utility and accuracy than either alone. We use our results to make practical recommendations for future target capture-based studies of Burmeistera and other rapid angiosperm radiations, including that such studies should analyze supercontigs to maximize the phylogenetic information content of loci.

A four-locus phylogeny of rib-stiped cupulate species of Helvella (Helvellaceae, Pezizales) with discovery of three new species

Helvella species are ascomycetous macrofungi with saddle-shaped or cupulate apothecia. They are distributed worldwide and play an important ecological role as ectomycorrhizal symbionts. A recent multi-locus phylogenetic study of the genus suggested that the cupulate group of Helvella was in need of comprehensive revision. In this study, all the specimens of cupulate Helvella sensu lato with ribbed stipes deposited in HMAS were examined morphologically and molecularly. A four-locus phylogeny was reconstructed using partial sequences of the heat shock protein 90, nuclear rDNA internal transcribed spacer region 2, nuclear large subunit ribosomal DNA and translation elongation factor 1-α genes. Three clades were revealed in Helvella sensu stricto. Twenty species were included in the analysis, of which 13 are distributed in China. Three new species, H.acetabuloides, H.sichuanensis and H.tianshanensis, are described and illustrated in detail. A neotype was designated for H.taiyuanensis. Helvellacalycina is a new record for China, while Dissingialeucomelaena should be excluded from Chinese mycota. Hsp90 and ITS2 are recommended as useful supplementary barcodes for species identifications of the genus.

Pindara revisited - evolution and generic limits in Helvellaceae

The Helvellaceae encompasses taxa that produce some of the most elaborate apothecial forms, as well as hypogeous ascomata, in the class Pezizomycetes (Ascomycota). While the circumscription of the Helvellaceae is clarified, evolutionary relationships and generic limits within the family are debatable. A robust phylogeny of the Helvellaceae, using an increased number of molecular characters from the LSU rDNA, RPB2 and EF-1α gene regions (4 299 bp) and a wide representative sampling, is presented here. Helvella s.lat. was shown to be polyphyletic, because Helvella aestivalis formed a distant monophyletic group with hypogeous species of Balsamia and Barssia. All other species of Helvella formed a large group with the enigmatic Pindara (/Helvella) terrestris nested within it. The ear-shaped Wynnella constitutes an independent lineage and is recognised with the earlier name Midotis. The clade of the hypogeous Balsamia and Barssia, and H. aestivalis is coherent in the three-gene phylogeny, and considering the lack of phenotypic characters to distinguish Barssia from Balsamia we combine species of Barssia, along with H. aestivalis, in Balsamia. The closed/tuberiform, sparassoid H. astieri is shown to be a synonym of H. lactea; it is merely an incidental folded form of the saddle-shaped H. lactea. Pindara is a sister group to a restricted Helvella, i.e., excluding the /leucomelaena lineage, on a notably long branch. We recognise Pindara as a separate genus and erect a new genus Dissingia for the /leucomelaena lineage, viz. H. confusa, H. crassitunicata, H. leucomelaena and H. oblongispora. Dissingia is supported by asci that arise from simple septa; all other species of Helvellaceae have asci that arise from croziers, with one exception being the /alpina-corium lineage of Helvella s.str. This suggests ascus development from croziers is the ancestral state for the Helvellaceae and that ascus development from simple septa has evolved at least twice in the family. Our phylogeny does not determine the evolutionary relationships within Helvella s.str., but it is most parsimonious to infer that the ancestor of the helvelloids produced subsessile or shortly stipitate, cup-shaped apothecia. This shape has been maintained in some lineages of Helvella s.str. The type species of Underwoodia, Underwoodia columnaris, is a sister lineage to the rest of the Helvellaceae.

Maximizing Power in Phylogenetics and Phylogenomics: A Perspective Illuminated by Fungal Big Data

Since its original inception over 150 years ago by Darwin, we have made tremendous progress toward the reconstruction of the Tree of Life. In particular, the transition from analyzing datasets comprised of small numbers of loci to those comprised of hundreds of loci, if not entire genomes, has aided in resolving some of the most vexing of evolutionary problems while giving us a new perspective on biodiversity. Correspondingly, phylogenetic trees have taken a central role in fields that span ecology, conservation, and medicine. However, the rise of big data has also presented phylogenomicists with a new set of challenges to experimental design, quantitative analyses, and computation. The sequencing of a number of very first genomes presented significant challenges to phylogenetic inference, leading fungal phylogenomicists to begin addressing pitfalls and postulating solutions to the issues that arise from genome-scale analyses relevant to any lineage across the Tree of Life. Here we highlight insights from fungal phylogenomics for topics including systematics and species delimitation, ecological and phenotypic diversification, and biogeography while providing an overview of progress made on the reconstruction of the fungal Tree of Life. Finally, we provide a review of considerations to phylogenomic experimental design for robust tree inference. We hope that this special issue of Advances in Genetics not only excites the continued progress of fungal evolutionary biology but also motivates the interdisciplinary development of new theory and methods designed to maximize the power of genomic scale data in phylogenetic analyses.

A synopsis of the saddle fungi (Helvella: Ascomycota) in Europe - species delimitation, taxonomy and typification

Helvella is a widespread, speciose genus of large apothecial ascomycetes (Pezizomycete: Pezizales) that are found in terrestrial biomes of the Northern and Southern Hemispheres. This study represents a beginning on assessing species limits and applying correct names for Helvella species based on type material and specimens in the university herbaria (fungaria) of Copenhagen (C), Harvard (FH) and Oslo (O). We use morphology and phylogenetic evidence from four loci – heat shock protein 90 (hsp), translation elongation factor alpha (tef), RNA polymerase II (rpb2) and the nuclear large subunit ribosomal DNA (LSU) – to assess species boundaries in an expanded sample of Helvella specimens from Europe. We combine the morphological and phylogenetic information from 55 Helvella species from Europe with a small sample of Helvella species from other regions of the world. Little intraspecific variation was detected within the species using these molecular markers; hsp and rpb2 markers provided useful barcodes for species delimitation in this genus, while LSU provided more variable resolution among the pertinent species. We discuss typification issues and identify molecular characteristics for 55 European Helvella species, designate neo- and epitypes for 30 species, and describe seven Helvella species new to science, i.e., H. alpicola, H. alpina, H. carnosa, H. danica, H. nannfeldtii, H. pubescens and H. scyphoides.

PhyInformR: phylogenetic experimental design and phylogenomic data exploration in R

Background

Analyses of phylogenetic informativeness represent an important step in screening potential or existing datasets for their proclivity toward convergent or parallel evolution of molecular sites. However, while new theory has been developed from which to predict the utility of sequence data, adoption of these advances have been stymied by a lack of software enabling application of advances in theory, especially for large next-generation sequence data sets. Moreover, there are no theoretical barriers to application of the phylogenetic informativeness or the calculation of quartet internode resolution probabilities in a Bayesian setting that more robustly accounts for uncertainty, yet there is no software with which a computationally intensive Bayesian approach to experimental design could be implemented.

Results

We introduce PhyInformR, an open source software package that performs rapid calculation of phylogenetic information content using the latest advances in phylogenetic informativeness based theory. These advances include modifications that incorporate uneven branch lengths and any model of nucleotide substitution to provide assessments of the phylogenetic utility of any given dataset or dataset partition. PhyInformR provides new tools for data visualization and routines optimized for rapid statistical calculations, including approaches making use of Bayesian posterior distributions and parallel processing. By implementing the computation on user hardware, PhyInformR increases the potential power users can apply toward screening datasets for phylogenetic/genomic information content by orders of magnitude.

Conclusions

PhyInformR provides a means to implement diverse substitution models and specify uneven branch lengths for phylogenetic informativeness or calculations providing quartet based probabilities of resolution, produce novel visualizations, and facilitate analyses of next-generation sequence datasets while incorporating phylogenetic uncertainty through the use parallel processing. As an open source program, PhyInformR is fully customizable and expandable, thereby allowing for advanced methodologies to be readily integrated into local bioinformatics pipelines.

Software is available through CRAN and a package containing the software, a detailed manual, and additional sample data is also provided freely through github: https://github.com/carolinafishes/PhyInformR.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-016-0837-3) contains supplementary material, which is available to authorized users.