A new species and a new record of Laccaria (Fungi, Basidiomycota) found in a relict forest of the endangered Fagus grandifolia var. mexicana

Assembly collapsing versus heterozygosity oversizing: detection of homokaryotic and heterokaryotic Laccaria trichodermophora strains by hybrid genome assembly

Genome assembly and annotation using short-paired reads is challenging for eukaryotic organisms due to their large size, variable ploidy and large number of repetitive elements. However, the use of single-molecule long reads improves assembly quality (completeness and contiguity), but haplotype duplications still pose assembly challenges. To address the effect of read length on genome assembly quality, gene prediction and annotation, we compared genome assemblers and sequencing technologies with four strains of the ectomycorrhizal fungus Laccaria trichodermophora. By analysing the predicted repertoire of carbohydrate enzymes, we investigated the effects of assembly quality on functional inferences. Libraries were generated using three different sequencing platforms (Illumina Next-Seq, Mi-Seq and PacBio Sequel), and genomes were assembled using single and hybrid assemblies/libraries. Long reads or hybrid assemby resolved the collapsing of repeated regions, but the nuclear heterozygous versions remained unresolved. In dikaryotic fungi, each cell includes two nuclei and each nucleus has differences not only in allelic gene version but also in gene composition and synteny. These heterokaryotic cells produce fragmentation and size overestimation of the genome assembly of each nucleus. Hybrid assembly revealed a wider functional diversity of genomes. Here, several predicted oxidizing activities on glycosyl residues of oligosaccharides and several chitooligosaccharide acetylase activities would have passed unnoticed in short-read assemblies. Also, the size and fragmentation of the genome assembly, in combination with heterozygosity analysis, allowed us to distinguish homokaryotic and heterokaryotic strains isolated from L. trichodermophora fruit bodies.

Three New Species of Laccaria (Hydnangiaceae) from India (Darjeeling Hills) Based on Molecular and Morphological Evidence

Three new species of Laccaria infundibuliformis, L. pallidus, and L. darjeelingensis, collected from Darjeeling, India, are described based on morphological and molecular evidence. Laccaria infundibuliformis is characterized by its small infundibuliform basidiocarps, and echinulate basidiospores with spines up to 1.36 µm long. Laccaria pallidus is characterized by medium-sized greyish-red basidiocarps, and echinulate basidiospores with spines up to 1.9 µm long. Laccaria darjeelingensis is characterized by dull red basidiocarps, and echinulate basidiospores with spines up to 1.27 µm long. Altogether, the study shows that these three Laccaria species are previously unknown to science.

Morphology and Molecular Phylogeny Reveal Five New Species of Laccaria (Hydnangiaceae, Agaricales) from Southern China

The genus Laccaria is a type of cosmopolitan and ecologically important fungal group. Members can form ectomycorrhizal associations with numerous trees, and some species are common edible fungi in local markets. Although some new species from China are recently published, the species diversity of Laccaria is still unclear in China. In this study, some samples of Laccaria were collected from southern China, and morphological characteristics and phylogenetic analyses based on the multilocus dataset of ITS-LSU-tef1-rpb2 confirmed five new species. Laccaria miniata, L. nanlingensis and L. neovinaceoavellanea were collected from subtropical broad-leaved forests, and L. rufobrunnea and L. umbilicata were collected from subtropical mixed forests of southwest China. Full descriptions, illustrations, comparisons with similar species and phylogenetic analysis are provided.

Fungal diversity notes 1387-1511: taxonomic and phylogenetic contributions on genera and species of fungal taxa

This article is the 13th contribution in the Fungal Diversity Notes series, wherein 125 taxa from four phyla, ten classes, 31 orders, 69 families, 92 genera and three genera incertae sedis are treated, demonstrating worldwide and geographic distribution. Fungal taxa described and illustrated in the present study include three new genera, 69 new species, one new combination, one reference specimen and 51 new records on new hosts and new geographical distributions. Three new genera, Cylindrotorula (Torulaceae), Scolecoleotia (Leotiales genus incertae sedis) and Xenovaginatispora (Lindomycetaceae) are introduced based on distinct phylogenetic lineages and unique morphologies. Newly described species are Aspergillus lannaensis, Cercophora dulciaquae, Cladophialophora aquatica, Coprinellus punjabensis, Cortinarius alutarius, C. mammillatus, C. quercoflocculosus, Coryneum fagi, Cruentomycena uttarakhandina, Cryptocoryneum rosae, Cyathus uniperidiolus, Cylindrotorula indica, Diaporthe chamaeropicola, Didymella azollae, Diplodia alanphillipsii, Dothiora coronicola, Efibula rodriguezarmasiae, Erysiphe salicicola, Fusarium queenslandicum, Geastrum gorgonicum, G. hansagiense, Helicosporium sexualis, Helminthosporium chiangraiensis, Hongkongmyces kokensis, Hydrophilomyces hydraenae, Hygrocybe boertmannii, Hyphoderma australosetigerum, Hyphodontia yunnanensis, Khaleijomyces umikazeana, Laboulbenia divisa, Laboulbenia triarthronis, Laccaria populina, Lactarius pallidozonarius, Lepidosphaeria strobelii, Longipedicellata megafusiformis, Lophiotrema lincangensis, Marasmius benghalensis, M. jinfoshanensis, M. subtropicus, Mariannaea camelliae, Melanographium smilaxii, Microbotryum polycnemoides, Mimeomyces digitatus, Minutisphaera thailandensis, Mortierella solitaria, Mucor harpali, Nigrograna jinghongensis, Odontia huanrenensis, O. parvispina, Paraconiothyrium ajrekarii, Parafuscosporella niloticus, Phaeocytostroma yomensis, Phaeoisaria synnematicus, Phanerochaete hainanensis, Pleopunctum thailandicum, Pleurotheciella dimorphospora, Pseudochaetosphaeronema chiangraiense, Pseudodactylaria albicolonia, Rhexoacrodictys nigrospora, Russula paravioleipes, Scolecoleotia eriocamporesi, Seriascoma honghense, Synandromyces makranczyi, Thyridaria aureobrunnea, Torula lancangjiangensis, Tubeufia longihelicospora, Wicklowia fusiformispora, Xenovaginatispora phichaiensis and Xylaria apiospora. One new combination, Pseudobactrodesmium stilboideus is proposed. A reference specimen of Comoclathris permunda is designated. New host or distribution records are provided for Acrocalymma fici, Aliquandostipite khaoyaiensis, Camarosporidiella laburni, Canalisporium caribense, Chaetoscutula juniperi, Chlorophyllum demangei, C. globosum, C. hortense, Cladophialophora abundans, Dendryphion hydei, Diaporthe foeniculina, D. pseudophoenicicola, D. pyracanthae, Dictyosporium pandanicola, Dyfrolomyces distoseptatus, Ernakulamia tanakae, Eutypa flavovirens, E. lata, Favolus septatus, Fusarium atrovinosum, F. clavum, Helicosporium luteosporum, Hermatomyces nabanheensis, Hermatomyces sphaericoides, Longipedicellata aquatica, Lophiostoma caudata, L. clematidis-vitalbae, Lophiotrema hydei, L. neoarundinaria, Marasmiellus palmivorus, Megacapitula villosa, Micropsalliota globocystis, M. gracilis, Montagnula thailandica, Neohelicosporium irregulare, N. parisporum, Paradictyoarthrinium diffractum, Phaeoisaria aquatica, Poaceascoma taiwanense, Saproamanita manicata, Spegazzinia camelliae, Submersispora variabilis, Thyronectria caudata, T. mackenziei, Tubeufia chiangmaiensis, T. roseohelicospora, Vaginatispora nypae, Wicklowia submersa, Xanthagaricus necopinatus and Xylaria haemorrhoidalis. The data presented herein are based on morphological examination of fresh specimens, coupled with analysis of phylogenetic sequence data to better integrate taxa into appropriate taxonomic ranks and infer their evolutionary relationships.

Novel Laccaria Species From Juglandaceae Forest in Panama With Notes on Their Ecology

Since 2013 there have been 22 new species of Laccaria described worldwide. Only three of these represent species from the neotropics. In Panama, Laccaria is abundant in monodominant Oreomunnea mexicana (Juglandaceae) forests based on sporocarps and environmental sequencing of roots. This study uses a combination of morphological and phylogenetic evidence to document up to seven species of Laccaria from these forests, one previously described, three described as new, and three requiring more data before being formally described. Molecular data used for phylogenetic analysis include the nuclear ribosomal ITS and 28S regions, along with TEF1 and RPB2. Laccaria stellata, has previously been reported from O. mexicana cloud forests of Panama. Laccaria dallingii sp. nov., L. nitrophila sp. nov., and L. fortunensis sp. nov. are described as new based on morphology and phylogenetic analysis of multiple collections. A taxon referred to as “PAN sp3” is resolved sister to L. stellata. Phylogenetic analysis also resolved two separate clades of Panamanian Laccaria as sister to L. roseoalbescens, a species previously described from Mexico. These three taxa are not described in this paper as there is too little material from which to make effective morphological descriptions even though their placement in phylogenetic analysis identify them as being unique. Ecologically, all described species except for L. fortunensis were amplified from O. mexicana ectomycorrhizal root tips. L. nitrophila was one of the most recovered species from the roots of O. mexicana in a previous study, and it has been shown to respond positively to long term nitrogen addition. Our results expand the knowledge of Laccaria diversity for Central America and highlight that at least some species of Laccaria are nitrophilic in neotropical Juglandaceae forests as well as in temperate forests.

Pyrophilous fungi detected after wildfires in the Great Smoky Mountains National Park expand known species ranges and biodiversity estimates

Following a late fall wildfire in 2016 in the Great Smoky Mountains National Park, pyrophilous fungi in burn zones were documented over a 2-y period with respect to burn severity and phenology. Nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) barcodes were obtained to confirm morphological evaluations. Forty-one taxa of Ascomycota and Basidiomycota were identified from burn sites and categorized as fruiting only in response to fire or fruiting enhanced by fire. Twenty-two species of Pezizales (Ascomycota) were among the earliest to form ascomata in severe burn zones, only one of which had previously been documented in the Great Smoky Mountains National Park. Nineteen species of Basidiomycota, primarily Agaricales, were also documented. Among these, only five species (Coprinellus angulatus, Gymnopilus decipiens, Lyophyllum anthracophilum, Pholiota carbonicola, and Psathyrella pennata) were considered to be obligate pyrophilous taxa, but fruiting of two additional taxa (Hygrocybe conica and Mycena galericulata) was clearly enhanced by fire. Laccaria trichodermophora was an early colonizer of severe burn sites and persisted through the winter of 2017 and into spring and summer of 2018, often appearing in close association with Pinus pungens seedlings. Fruiting of pyrophilous fungi peaked 4-6 mo post fire then diminished, but some continued to fruit up to 2.5 y after the fire. In all, a total of 27 previously unrecorded taxa were added to the All Taxa Biodiversity Inventory (ATBI) database (~0.9%). Most pyrophilous fungi identified in this study are either cosmopolitan or have a Northern Hemisphere distribution, but cryptic endemic lineages were detected in Anthracobia and Sphaerosporella. One new combination, Hygrocybe spadicea var. spadicea f. odora, is proposed.

The complete mitochondrial genomes of two model ectomycorrhizal fungi (Laccaria): features, intron dynamics and phylogenetic implications

Laccaria amethystine and L. bicolor have served as model species for studying the life history and genetics of ectomycorrhizal fungi. However, the characterizations and variations of their mitogenomes are still unknown. In the present study, the mitogenomes of the two Laccaria species were assembled, annotated, and compared. The two mitogenomes of L. amethystine and L. bicolor comprised circular DNA molecules, with the sizes of 65,156 bp and 95,304 bp, respectively. Genome collinearity analysis revealed large-scale gene rearrangements between the two Laccaria species. Comparative mitogenome analysis indicated the introns of cox1 genes in Agaricales experienced frequent lost/gain eveants, which promoted the organization and size variations in Agaricales mitogenomes. Evolutionary analysis indicated the core protein-coding genes in the two mitogenomes were subject to strong pressure of purifying selection. Phylogenetic analysis using the Bayesian inference (BI) and Maximum likelihood (ML) methods based on a combined mitochondrial gene set resulted in identical and well-supported tree topologies, wherein the two Laccaria species were most closely related to Coprinopsis cinerea. This study severed as the first study on the mitogenomes of Laccaria species, which promoted a comprehensive understanding of the genetics and evolution of the model ectomycorrhizal fungi.

Ectomycorrhizal fungi may not act as a barrier inhibiting host plant absorption of heavy metals

Whether the huge external hyphal system of ectomycorrhizae that promotes host plants' acquisition of water and nutrients can selectively inhibit their transport of heavy metals at the same time remains unclear. In this experiment, we designed and conducted two types of soil-pot test to clarify the effects of EMF on the absorption and transport of copper (Cu) and cadmium (Cd) by host Pinus thunbergii seedlings. In the root-bag test, external hyphae took the initiative into the Cu/Cd-contaminated bulk soil, absorb and transport Cu and Cd to the rhizosphere soils and further transport it to the shoots of the host plants. Inoculation with EMF also promoted the uptake of nutrients by host plants, thereby increasing their biomass and improving Cu/Cd tolerance compared with non-inoculated plants. Inoculation with EMF species with higher Cu or Cd tolerance generated more phytostabilization and phytoextraction of Cu or Cd by host plants. In a short-term exposure test, inoculation with EMF accelerated the absorption of Cu and Cd by P. thunbergii within 12 h of Cu or Cd irrigation. Therefore, we concluded that EMF do not act as a barrier inhibiting the absorption of heavy metals by host plants, but rather promote this absorption. Improving the plant's nutritional status and promoting growth, diluting heavy metal concentrations, thereby reducing the toxic effects of heavy metals on host plants. These results provide the theoretical basis for the application of EMF in plant-microbial combinations for the phytostabilization and phytoextraction of heavy metal-contaminated soils.