Core Ericaceae produce delicate hair roots with inflated rhizodermal cells that host plethora of fungal symbionts. These poorly known mycobionts include various endophytes, parasites, saprobes, and the ericoid mycorrhizal (ErM) fungi (ErMF) that form the ErM symbiosis crucial for the fitness of their hosts. Using microscopy and high-throughput sequencing, we investigated their structural and molecular diversity in 14 different host × site combinations in Northern Bohemia (Central Europe) and Argentine Patagonia (South America). While we found typical ericoid mycorrhiza in all combinations, we did not detect ectomycorrhiza and arbuscular mycorrhiza. Superficial mantles of various thickness formed by non-clamped hyphae were observed in all combinations except Calluna vulgaris from N. Bohemia. Some samples contained frequent intercellular hyphae while others possessed previously unreported intracellular haustoria-like structures linked with intracellular hyphal coils. The 711 detected fungal OTU were dominated by Ascomycota (563) and Basidiomycota (119), followed by four other phyla. Ascomycetes comprised Helotiales (255), Pleosporales (53), Chaetothyriales (42), and other 19 orders, while basidiomycetes Sebacinales (42), Agaricales (28), Auriculariales (7), and other 14 orders. While many dominant OTU from both hemispheres lacked close relatives in reference databases, many were very similar to identical to unnamed sequences from around the world. On the other hand, several significant ericaceous mycobionts were absent in our dataset, incl. Cairneyella, Gamarada, Kurtia, Lachnum, and Leohumicola. Most of the detected OTU could not be reliably linked to a particular trophic mode, and only two could be reliably assigned to the archetypal ErMF Hyaloscypha hepaticicola. Probable ErMF comprised Hyaloscypha variabilis and Oidiodendron maius, both detected only in N. Bohemia. Possible ErMF comprised sebacinoid fungi and several unnamed members of Hyaloscypha s. str. While H. hepaticicola was dominant only in C. vulgaris, this model ErM host lacked O. maius and sebacinoid mycobionts. Hyaloscypha hepaticicola was absent in two and very rare in six combinations from Patagonia. Nine OTU represented dark septate endophytes from the Phialocephala fortinii s. lat.-Acephala applanata species complex, including the most abundant OTU (the only detected in all combinations). Statistical analyses revealed marked differences between N. Bohemia and Patagonia, but also within Patagonia, due to the unique community detected in a Valdivian temperate rainforest. Our results show that the ericaceous hair roots may host diverse mycobionts with mostly unknown functions and indicate that many novel ErMF lineages await discovery. Transhemispheric differences (thousands of km) in their communities may be evenly matched by local differences (scales of km, m, and less).

• Klíčová slova
• Central Europe, Ericoid mycorrhizal fungi, Fungal root endophytes, Helotiales, Hyaloscypha sp., Oidiodendron maius, Root-associated fungi, Sebacinales, South America,
• MeSH
• Ascomycota MeSH
• Basidiomycota * MeSH
• endofyty genetika   MeSH
• Ericaceae * mikrobiologie   MeSH
• kořeny rostlin mikrobiologie   MeSH
• mykorhiza * genetika   MeSH
• symbióza MeSH
• Publikační typ
• časopisecké články MeSH

Historically, Hyaloscypha s. lat. (Hyaloscyphaceae, Helotiales) included various saprobes with small apothecia formed on decaying plant matter, usually wood, that were defined by chemical and (ultra)structural aspects. However, recent molecular phylogenetic and resynthesis studies have narrowed the concept of the genus and shown that it contains several widely distributed species with unknown sexual morphs that form ectomycorrhizae, ericoid mycorrhizae, and mycothalli and also grow endophytically in plant roots and hypogeous ectomycorrhizal (EcM) fruitbodies (i.e., the historical Hymenoscyphus ericae aggregate). Hence, some of the sexually reproducing saprobic Hyaloscypha s. lat. and the symbionts belong to the monophyletic Hyaloscypha s. str. Here, we introduce two new root-symbiotic Hyaloscypha s. str. species, i.e., H. gabretae and H. gryndleri spp. nov. While the former was isolated only from ericaceous hosts (Vaccinium myrtillus from Southern Bohemia, Czechia and Calluna vulgaris from England, UK), the latter was obtained from a basidiomycetous EcM root tip of Picea abies (Pinaceae), roots of Pseudorchis albida (Orchidaceae), and hair roots of V. myrtillus from Southern Bohemia and C. vulgaris from England. Hyaloscypha gryndleri comprises two closely related lineages, suggesting ongoing speciation, possibly connected with the root-symbiotic life-style. Fungal isolates from ericaceous roots with sequences similar to H. gabretae and H. gryndleri have been obtained in Japan and in Canada and Norway, respectively, suggesting a wide and scattered distribution across the Northern Hemisphere. In a series of in vitro experiments, both new species failed to form orchid mycorrhizal structures in roots of P. albida and H. gryndleri repeatedly formed what morphologically corresponds to the ericoid mycorrhizal (ErM) symbiosis in hair roots of V. myrtillus, whereas the ErM potential of H. gabretae remained unresolved. Our results highlight the symbiotic plasticity of root-associated hyaloscyphoid mycobionts as well as our limited knowledge of their diversity and distribution, warranting further ecophysiological and taxonomic research of these important and widespread fungi.

• Klíčová slova
• Core Ericaceae, Ericoid mycorrhizal fungi, Hyaloscypha hepaticicola, Hymenoscyphus ericae, Meliniomyces, Pezoloma ericae, Rhizoscyphus ericae, Root symbiotic fungi,
• MeSH
• Ascomycota * MeSH
• cévnaté rostliny * MeSH
• fylogeneze MeSH
• kořeny rostlin MeSH
• mykorhiza * genetika   MeSH
• Publikační typ
• časopisecké články MeSH

Belowground litter derived from tree roots has been shown as a principal source of soil organic matter in coniferous forests. Fate of tree root necromass depends on fungal communities developing on the decaying roots. Local environmental conditions which affect composition of tree root mycobiome may also influence fungal communities developing on decaying tree roots. Here, we assessed fungal communities associated with decaying roots of Picea abies decomposing in three microhabitats: soil with no vegetation, soil with ericoid shrubs cover, and P. abies deadwood, for a 2-year period. Forest microhabitat showed stronger effect on structuring fungal communities associated with decaying roots compared to living roots. Some ericoid mycorrhizal fungi showed higher relative abundance on decaying roots in soils under ericoid shrub cover, while saprotrophic fungi had higher relative abundance in roots decomposing inside deadwood. Regardless of the studied microhabitat, we observed decline of ectomycorrhizal fungi and increase of endophytic fungi during root decomposition. Interestingly, we found substantially more fungal taxa with unknown ecology in late stages of root decomposition, indicating that highly decomposed roots may represent so far overlooked niche for soil fungi. Our study shows the importance of microhabitats on the fate of the decomposing spruce roots.

• Klíčová slova
• Norway spruce, dark septate endophytes, forest ecosystem, forest microhabitats, fungal communities, root litter, soil organic matter, stem decapitation,
• Publikační typ
• časopisecké články MeSH

Despite decades of intensive research (especially from 1970s to 1990s), the ericoid mycorrhizal (ErM) hair root is still largely terra incognita and this simplified guide is intended to revive and promote the study of its mycobiota. Basic theoretical knowledge on the ErM symbiosis is summarized, followed by practical advices on Ericaceae root sample collection and handling, microscopic observations and photo-documentation of root fungal colonization, mycobiont isolation, maintenance and identification and resynthesis experiments with ericoid plants. The necessity of a proper selection of the root material and its surface sterilization prior to mycobiont isolation is stressed, together with the need of including suitable control treatments in inoculation experiments. The culture-dependent approach employing plating of single short (~ 2 mm) hair root segments on nutrient media is substantiated as a useful tool for characterization of Ericaceae root-associated fungal communities; it targets living mycelium and provides metabolically active cultures that can be used in physiological experiments and taxonomic studies, thus providing essential reference material for culture-independent approaches. On the other hand, it is stressed that not every mycobiont isolated from an ericoid hair root necessarily represent an ErM fungus. Likewise, not every intracellular hyphal coil formed in the Ericaceae rhizodermis necessarily represents the ErM symbiosis. Taxonomy of the most important ericoid mycobionts is updated, mutualism in the ErM symbiosis is briefly discussed from the mycobiont perspective, and some interesting lines of possible future research are highlighted.

• Klíčová slova
• Culture-dependent approach, Ericaceae, Ericoid mycorrhizal fungal diversity, In vitro resynthesis, Isolate identification, Microscopy, Mycobiont isolation, Plating of surface-sterilized root segments,
• MeSH
• Ericaceae * MeSH
• kořeny rostlin MeSH
• mykorhiza * MeSH
• rostliny MeSH
• symbióza MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Alien plants represent a potential threat to environment and society. Understanding the process of alien plants naturalization is therefore of primary importance. In alien plants, successful establishment can be constrained by the absence of suitable fungal partners. Here, we used 42 independent datasets of ectomycorrhizal fungal (EcMF) communities associated with alien Pinaceae and Eucalyptus spp., as the most commonly introduced tree species worldwide, to explore the strategies these plant groups utilize to establish symbioses with EcMF in the areas of introduction. We have also determined the differences in composition of EcMF communities associated with alien ectomycorrhizal plants in different regions. While alien Pinaceae introduced to new regions rely upon association with co-introduced EcMF, alien Eucalyptus often form novel interactions with EcMF species native to the region where the plant was introduced. The region of origin primarily determines species composition of EcMF communities associated with alien Pinaceae in new areas, which may largely affect invasion potential of the alien plants. Our study shows that alien ectomycorrhizal plants largely differ in their ability to interact with co-introduced and native ectomycorrhizal fungi in sites of introduction, which may potentially affect their invasive potential.

• MeSH
• mykorhiza * MeSH
• rostliny MeSH
• stromy MeSH
• symbióza MeSH
• zavlečené druhy MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Data mining for a phylogenetic study including the prominent ericoid mycorrhizal fungus Rhizoscyphus ericae revealed nearly identical ITS sequences of the bryophilous Hyaloscypha hepaticicola suggesting they are conspecific. Additional genetic markers and a broader taxonomic sampling furthermore suggested that the sexual Hyaloscypha and the asexual Meliniomyces may be congeneric. In order to further elucidate these issues, type strains of all species traditionally treated as members of the Rhizoscyphus ericae aggregate (REA) and related taxa were subjected to phylogenetic analyses based on ITS, nrLSU, mtSSU, and rpb2 markers to produce comparable datasets while an in vitro re-synthesis experiment was conducted to examine the root-symbiotic potential of H. hepaticicola in the Ericaceae. Phylogenetic evidence demonstrates that sterile root-associated Meliniomyces, sexual Hyaloscypha and Rhizoscyphus, based on R. ericae, are indeed congeneric. To this monophylum also belongs the phialidic dematiaceous hyphomycetes Cadophora finlandica and Chloridium paucisporum. We provide a taxonomic revision of the REA; Meliniomyces and Rhizoscyphus are reduced to synonymy under Hyaloscypha. Pseudaegerita, typified by P. corticalis, an asexual morph of H. spiralis which is a core member of Hyaloscypha, is also transferred to the synonymy of the latter genus. Hyaloscypha melinii is introduced as a new root-symbiotic species from Central Europe. Cadophora finlandica and C. paucisporum are confirmed conspecific, and four new combinations in Hyaloscypha are proposed. Based on phylogenetic analyses, some sexually reproducing species can be attributed to their asexual counterparts for the first time whereas the majority is so far known only in the sexual or asexual state. Hyaloscypha bicolor sporulating in vitro is reported for the first time. Surprisingly, the mycological and mycorrhizal sides of the same coin have never been formally associated, mainly because the sexual and asexual morphs of these fungi have been studied in isolation by different research communities. Evaluating all these aspects allowed us to stabilize the taxonomy of a widespread and ecologically well-studied group of root-associated fungi and to link their various life-styles including saprobes, bryophilous fungi, root endophytes as well as fungi forming ericoid mycorrhizae and ectomycorrhizae.

• Klíčová slova
• Ectomycorrhiza, Ericoid mycorrhiza, Hyaloscypha bicolor (Hambl. & Sigler) Vohník, Fehrer & Réblová, Hyaloscypha finlandica (C.J.K. Wang & H.E. Wilcox) Vohník, Fehrer & Réblová, Hyaloscypha hepaticicola, Hyaloscypha melinii Vohník, Fehrer & Réblová, Hyaloscypha variabilis (Hambl. & Sigler) Vohník, Fehrer & Réblová, Hyaloscypha vraolstadiae (Hambl. & Sigler) Vohník, Fehrer & Réblová, Hymenoscyphus ericae, Meliniomyces, Molecular systematics, Mycorrhizal synthesis, Pezoloma ericae, Pseudaegerita, Sexual-asexual connection,
• Publikační typ
• časopisecké články MeSH

Ericoid mycorrhiza is arguably the least investigated mycorrhizal type, particularly when related to the number of potential hosts and the ecosystems they inhabit. Little is known about the global distribution of ericoid mycorrhizal (ErM) fungi, and this holds true even for the prominent ErM mycobiont Rhizoscyphus ericae. Earlier studies suggested R. ericae might be low in abundance or absent in the roots of Southern Hemisphere's Ericaceae, and our previous investigations in two Argentine Patagonian forests supported this view. Here, we revisited the formerly investigated area, albeit at a higher altitude, and screened fungi inhabiting hair roots of Gaultheria caespitosa and Gaultheria pumila at a treeless alpine site using the same methods as previously. We obtained 234 isolates, most of them belonging to Ascomycota. In contrast to previous findings, however, among 37 detected operational taxonomic units (OTUs), OTU 1 (=R. ericae s. str.) comprised the highest number of isolates (87, ∼37 %). Most of the OTUs and isolates belonged to the Helotiales, and 82.5 % of isolates belonged to OTUs shared between both Gaultheria species. At the alpine site, ericoid mycorrhizal fungi dominated, followed by dark septate endophytes and aquatic hyphomycetes probably acting as root endophytes. Our results suggest that the distribution of R. ericae is influenced, among others, by factors related to altitude such as soil type and presence/absence and type of the neighboring vegetation. Our study is the first report on R. ericae colonizing Ericaceae roots in the Southern Hemisphere and extends the known range of this prominent ErM species to NW Patagonia.

• Klíčová slova
• Ericaceae, Ericoid mycorrhiza, Global distribution, Hymenoscyphus ericae, Pezoloma ericae, Southern Hemisphere,
• MeSH
• Ericaceae mikrobiologie   MeSH
• fylogeneze MeSH
• Glomeromycota klasifikace   genetika   izolace a purifikace   MeSH
• kořeny rostlin mikrobiologie   MeSH
• mykorhiza fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Argentina MeSH

The unresolved ecophysiological significance of Dark Septate Endophytes (DSE) may be in part due to existence of morphologically indistinguishable cryptic species in the most common Phialocephala fortinii s. l.--Acephala applanata species complex (PAC). We inoculated three middle European forest plants (European blueberry, Norway spruce and silver birch) with 16 strains of eight PAC cryptic species and other DSE and ectomycorrhizal/ericoid mycorrhizal fungi and focused on intraradical structures possibly representing interfaces for plant-fungus nutrient transfer and on host growth response. The PAC species Acephala applanata simultaneously formed structures resembling ericoid mycorrhiza (ErM) and DSE microsclerotia in blueberry. A. macrosclerotiorum, a close relative to PAC, formed ectomycorrhizae with spruce but not with birch, and structures resembling ErM in blueberry. Phialocephala glacialis, another close relative to PAC, formed structures resembling ErM in blueberry. In blueberry, six PAC strains significantly decreased dry shoot biomass compared to ErM control. In birch, one A. macrosclerotiorum strain increased root biomass and the other shoot biomass in comparison with non-inoculated control. The dual mycorrhizal ability of A. macrosclerotiorum suggested that it may form mycorrhizal links between Ericaceae and Pinaceae. However, we were unable to detect this species in Ericaceae roots growing in a forest with presence of A. macrosclerotiorum ectomycorrhizae. Nevertheless, the diversity of Ericaceae mycobionts was high (380 OTUs) with individual sites often dominated by hitherto unreported helotialean and chaetothyrialean/verrucarialean species; in contrast, typical ErM fungi were either absent or low in abundance. Some DSE apparently have a potential to form mycorrhizae with typical middle European forest plants. However, except A. applanata, the tested representatives of all hitherto described PAC cryptic species formed typical DSE colonization without specific structures necessary for mycorrhizal nutrient transport. A. macrosclerotiorum forms ectomycorrhiza with conifers but not with broadleaves and probably does not form common mycorrhizal networks between conifers with Ericaceae.

• MeSH
• endofyty MeSH
• kořeny rostlin mikrobiologie   MeSH
• mykorhiza fyziologie   MeSH
• smrk mikrobiologie   MeSH
• symbióza * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH

Ericaceae (the heath family) are widely distributed calcifuges inhabiting soils with inherently poor nutrient status. Ericaceae overcome nutrient limitation through symbiosis with ericoid mycorrhizal (ErM) fungi that mobilize nutrients complexed in recalcitrant organic matter. At present, recognized ErM fungi include a narrow taxonomic range within the Ascomycota, and the Sebacinales, basal Hymenomycetes with unclamped hyphae and imperforate parenthesomes. Here we describe a novel type of basidiomycetous ErM symbiosis, termed 'sheathed ericoid mycorrhiza', discovered in two habitats in mid-Norway as a co-dominant mycorrhizal symbiosis in Vaccinium spp. The basidiomycete forming sheathed ErM possesses clamped hyphae with perforate parenthesomes, produces 1- to 3-layer sheaths around terminal parts of hair roots and colonizes their rhizodermis intracellularly forming hyphal coils typical for ErM symbiosis. Two basidiomycetous isolates were obtained from sheathed ErM and molecular and phylogenetic tools were used to determine their identity; they were also examined for the ability to form sheathed ErM and lignocellulolytic potential. Surprisingly, ITS rDNA of both conspecific isolates failed to amplify with the most commonly used primer pairs, including ITS1 and ITS1F + ITS4. Phylogenetic analysis of nuclear LSU, SSU and 5.8S rDNA indicates that the basidiomycete occupies a long branch residing in the proximity of Trechisporales and Hymenochaetales, but lacks a clear sequence relationship (>90% similarity) to fungi currently placed in these orders. The basidiomycete formed the characteristic sheathed ErM symbiosis and enhanced growth of Vaccinium spp. in vitro, and degraded a recalcitrant aromatic substrate that was left unaltered by common ErM ascomycetes. Our findings provide coherent evidence that this hitherto undescribed basidiomycete forms a morphologically distinct ErM symbiosis that may occur at significant levels under natural conditions, yet remain undetected when subject to amplification by 'universal' primers. The lignocellulolytic assay suggests the basidiomycete may confer host adaptations distinct from those provisioned by the so far investigated ascomycetous ErM fungi.

• MeSH
• Basidiomycota genetika   MeSH
• Ericaceae mikrobiologie   MeSH
• fylogeneze MeSH
• kořeny rostlin mikrobiologie   MeSH
• mykorhiza klasifikace   genetika   MeSH
• symbióza genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Norsko MeSH