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Martin Vohník - One of the best experts on this subject based on the ideXlab platform.
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when the ribosomal dna does not tell the truth the case of the taxonomic position of kurtia argillacea an Ericoid Mycorrhizal fungus residing among hymenochaetales
Fungal Biology, 2018Co-Authors: Miroslav Kolařik, Martin VohníkAbstract:Abstract The nuclear ribosomal DNA (nuc-rDNA) is widely used for the identification and phylogenetic reconstruction of Agaricomycetes. However, nuc-rDNA-based phylogenies may sometimes be in conflict with phylogenetic relationships derived from protein coding genes. In this study, the taxonomic position of the basidiomycetous mycobiont that forms the recently discovered sheathed Ericoid Mycorrhiza was investigated, because its nuc-rDNA is highly dissimilar to any other available fungal sequences in terms of nucleotide composition and length, and its nuc-rDNA-based phylogeny is inconclusive and significantly disagrees with protein coding sequences and morphological data. In the present work, this mycobiont was identified as Kurtia argillacea (= Hyphoderma argillaceum ) residing in the order Hymenochaetales (Basidiomycota). Bioinformatic screening of the Kurtia ribosomal DNA sequence indicates that it represents a gene with a non-standard substitution rate or nucleotide composition heterogeneity rather than a deep paralogue or a pseudogene. Such a phenomenon probably also occurs in other lineages of the Fungi and should be taken into consideration when nuc-rDNA (especially that with unusual nucleotide composition) is used as a sole marker for phylogenetic reconstructions. Kurtia argillacea so far represents the only confirmed non-sebacinoid Ericoid Mycorrhizal fungus in the Basidiomycota and its intriguing placement among mostly saprobic and parasitic Hymenochaetales begs further investigation of its eco-physiology.
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Experimental evidence of Ericoid Mycorrhizal potential within Serendipitaceae (Sebacinales)
Mycorrhiza, 2016Co-Authors: Martin Vohník, Matěj Pánek, Judith Fehrer, Marc-andré SelosseAbstract:The Sebacinales are a monophyletic group of ubiquitous hymenomycetous mycobionts which form Ericoid and orchid Mycorrhizae, ecto- and ectendoMycorrhizae, and nonspecific root endophytic associations with a wide spectrum of plants. However, due to the complete lack of fungal isolates derived from Ericaceae roots, the Sebacinales Ericoid Mycorrhizal (ErM) potential has not yet been tested experimentally. Here, we report for the first time isolation of a serendipitoid (formerly Sebacinales Group B) mycobiont from Ericaceae which survived in pure culture for several years. This allowed us to test its ability to form Ericoid Mycorrhizae with an Ericaceae host in vitro, to describe its development and colonization pattern in host roots over time, and to compare its performance with typical ErM fungi and other serendipitoids derived from non-Ericaceae hosts. Out of ten serendipitoid isolates tested, eight intracellularly colonized Vaccinium hair roots, but only the Ericaceae-derived isolate repeatedly formed typical Ericoid Mycorrhiza morphologically identical to Ericoid Mycorrhiza commonly found in naturally colonized Ericaceae, but yet different from Ericoid Mycorrhiza formed in vitro by the prominent ascomycetous ErM fungus Rhizoscyphus ericae . One Orchidaceae-derived isolate repeatedly formed abundant hyaline intracellular microsclerotia morphologically identical to those occasionally found in naturally colonized Ericaceae, and an isolate of Serendipita (= Piriformospora ) indica produced abundant intracellular chlamydospores typical of this species. Our results confirm for the first time experimentally that some Sebacinales can form Ericoid Mycorrhiza, point to their broad endophytic potential in Ericaceae hosts, and suggest possible Ericoid Mycorrhizal specificity in Serendipitaceae.
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the potential of dark septate endophytes to form root symbioses with ectoMycorrhizal and Ericoid Mycorrhizal middle european forest plants
PLOS ONE, 2015Co-Authors: Tereza Lukesova, Petr Kohout, Tomas Větrovský, Martin VohníkAbstract: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.
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Is the prominent Ericoid Mycorrhizal fungus Rhizoscyphus ericae absent in the Southern Hemisphere's Ericaceae? A case study on the diversity of root mycobionts in Gaultheria spp. from northwest Patagonia, Argentina.
Mycorrhiza, 2014Co-Authors: M. Clara Bruzone, Sonia B. Fontenla, Martin VohníkAbstract:Ericaceae diversity hotspots are in the mountains of the Neotropics and Papua New Guinea, South Africa’s fynbos and Southeast Asia but majority of references to their root mycobionts come from the Northern Hemisphere. Here, typical cultivable Ericoid Mycorrhizal (ErM) fungi comprise Rhizoscyphus ericae, Meliniomyces variabilis, and Oidiodendron maius. It is however unclear whether this is true also for the Southern Hemisphere. Our study focused on cultivable mycobionts from hair roots of Gaultheria mucronata and Gaultheria poeppigii (Ericaceae) from two natural forests in NW Patagonia, Argentina, differing in Mycorrhizal preferences of their tree dominants. We detected 62 well-defined OTUs mostly belonging to Helotiales and Hypocreales; the most frequent were Phialocephala fortinii s. l., Pochonia suchlasporia, and Ilyonectria radicicola. Only one out of 257 isolates showed ITS nrDNA similarity to members of the R. ericae aggregate (REA) but was not conspecific with R. ericae, and only five isolates were conspecific with O. maius. Microscopic observations showed that the screened roots were frequently colonized in a manner differing from the pattern typically produced by R. ericae and O. maius. A re-synthesis experiment with selected isolates showed that only O. maius formed colonization resembling Ericoid Mycorrhiza. Amplification of root fungal DNA with REA-specific and Sebacinaceae-specific primers showed that REA mycobionts were present in some of the screened samples while Sebacinaceae were present in all samples. These results suggest that Gaultheria spp. from NW Patagonia form Ericoid Mycorrhizae predominantly with the difficult-to-cultivate Sebacinaceae while the incidence of REA is relatively low and may be masked by other most likely non-Mycorrhizal cultivable mycobionts.
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novel root fungus symbiosis in ericaceae sheathed Ericoid Mycorrhiza formed by a hitherto undescribed basidiomycete with affinities to trechisporales
PLOS ONE, 2012Co-Authors: Martin Vohník, Petr Kohout, Jesse J Sadowsky, Zuzana Lhotakova, Rolf Nestby, Miroslav KolařikAbstract: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.
David Read - One of the best experts on this subject based on the ideXlab platform.
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Lignin and soluble phenolic degradation by ectoMycorrhizal and Ericoid Mycorrhizal fungi
Fungal Biology, 1997Co-Authors: Gary D. Bending, David ReadAbstract:The organic soil horizons of heathland and temperate forest ecosystems are characteristically rich in phenolics, which present barriers to organic N availability to the microflora. The abilities of ectoMycorrhizal (ECM), Ericoid Mycorrhizal and wood decomposing saprotrophic fungi to degrade model compounds representing the insoluble phenolic lignin, and soluble phenolics, which provide physical and chemical barriers respectively to organic N availability, were compared. No clear relationship was found between ability to degrade lignin and soluble phenolics. The presumptive assays indicated that most Mycorrhizal fungi have only low abilities to degrade these compounds relative to the wood decomposing fungi. In general, Ericoid Mycorrhiza fungi were capable of greater phenolic degradation than most ECM species, and degradative ability was associated with production of phenol-oxidizing enzymes. In no case was presumptive degradation of lignin or soluble phenolic, or production of phenol-oxidizing enzymes by Mycorrhizal fungi as great as that of the wood decomposing fungi. In the case of the Ericoid endophyte Hymenoscyphus ericae , phenol-oxidation was associated with production of an extracellular o-polyphenol oxidase (tyrosinase) which showed optimal activity at a pH of 5–5.5 and temperature of 30°C. The ecological significance of the results is discussed.
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Ericoid Mycorrhizas and rhizoid ascomycete associations in liverworts share the same mycobiont isolation of the partners and resynthesis of the associations in vitro
New Phytologist, 1995Co-Authors: Jeffrey G. Duckett, David ReadAbstract:SUMMARY The hypothesis was tested that rhizoids of leafy liverworts of the families Lepidoziaceae, Calypogeiaceae, Cephaloziaceae and Cephaloziellaceae can be infected by the ascomycetous fungal endophyte Hymenoscyphus ericae which forms Ericoid Mycorrhiza with the major ericaceous genera Calluna, Erica, Rhododendron and Vaccinium. The extent of the specificity of any such association was also examined by growing the liverworts with pure cultures of the putative ascomycetous Ericoid endophyte Oidiodendron, with the basidiomycetous endophyte of orchids, Ceratobasidium cornigerum, and with several ectoMycorrhizal fungi. It was confirmed that the members of these liverwort families tested, most of which are associated in nature with ericaceous plants, were readily infected by H. ericae, as well as by isolates obtained from the liverworts themselves. The latter, when used to challenge aseptically grown seedlings of the ericaceous genera on water agar, produced typical Ericoid Mycorrhiza. Neither the Oidiodendron isolates nor the orchid or ectoMycorrhizal fungi infected the liverworts, and all failed to reproduce the characteristic swelling of the rhizoid tips which is seen in nature and in plants inoculated with H. ericae.
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experiments with Ericoid Mycorrhiza
Methods in Microbiology, 1991Co-Authors: Jonathan R. Leake, David ReadAbstract:Publisher Summary This chapter discusses experiments with Ericoid Mycorrhiza. There is a description of the procedures for isolation, culture, and re-inoculation of the Mycorrhizal endophyte. The extent to which systematic experimental analysis of the response of host plants to infection has enabled justifiably to apply the term “Mycorrhizal” to the relationship between H. ericae and its host plants is then examined. The reductionist approach to analysis of Mycorrhizal function, exemplified most widely by experiments in which the processes of uptake of a single mineral ion are studied under controlled conditions, has provided valuable insights into some of the specific mechanisms which may be in operation in natural communities. The challenge is to determine the true nature of the resources being exploited by Mycorrhizal roots in the far more complex soil environment, and to evaluate the extent to which interactions within and between heterotrophic and autotrophic populations influence the expression of Mycorrhizal potential.
Elena Martino - One of the best experts on this subject based on the ideXlab platform.
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The hydrophobin-like OmSSP1 may be an effector in the Ericoid Mycorrhizal symbiosis
Frontiers in plant science, 2018Co-Authors: Salvatore Casarrubia, Francis Martin, Silvia Perotto, Stefania Daghino, Emmanuelle Morin, Hassine Radhouane Khouja, Yohann Daguerre, Claire Veneault-fourrey, Elena MartinoAbstract:Mutualistic and pathogenic plant-colonizing fungi use effector molecules to manipulate the host cell metabolism to allow plant tissue invasion. Some small secreted proteins (SSPs) have been identified as fungal effectors in both ectoMycorrhizal and arbuscular Mycorrhizal fungi, but it is currently unknown whether SSPs also play a role as effectors in other Mycorrhizal associations. Ericoid Mycorrhiza is a specific endoMycorrhizal type that involves symbiotic fungi mostly belonging to the Leotiomycetes (Ascomycetes) and plants in the family Ericaceae. Genomic and RNASeq data from the Ericoid Mycorrhizal fungus Oidiodendron maius led to the identification of several symbiosis-upregulated genes encoding putative SSPs. OmSSP1, the most highly symbiosis up-regulated SSP, was found to share some features with fungal hydrophobins, even though it lacks the Pfam hydrophobin domain. Sequence alignment with other hydrophobins and hydrophobin-like fungal proteins placed OmSSP1 within Class I hydrophobins. However, the predicted features of OmSSP1 may suggest a distinct type of hydrophobin-like proteins. The presence of a predicted signal peptide and a yeast-based signal sequence trap assay demonstrate that OmSSP1 is secreted. OmSSP1 null-mutants showed a reduced capacity to form Ericoid Mycorrhiza with Vaccinium myrtillus roots, suggesting a role as effectors in the Ericoid Mycorrhizal interaction.
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Data_Sheet_1_The Hydrophobin-Like OmSSP1 May Be an Effector in the Ericoid Mycorrhizal Symbiosis.docx
2018Co-Authors: Salvatore Casarrubia, Silvia Perotto, Stefania Daghino, Emmanuelle Morin, Hassine Radhouane Khouja, Yohann Daguerre, Claire Veneault-fourrey, Francis M. Martin, Elena MartinoAbstract:Mutualistic and pathogenic plant-colonizing fungi use effector molecules to manipulate the host cell metabolism to allow plant tissue invasion. Some small secreted proteins (SSPs) have been identified as fungal effectors in both ectoMycorrhizal and arbuscular Mycorrhizal fungi, but it is currently unknown whether SSPs also play a role as effectors in other Mycorrhizal associations. Ericoid Mycorrhiza is a specific endoMycorrhizal type that involves symbiotic fungi mostly belonging to the Leotiomycetes (Ascomycetes) and plants in the family Ericaceae. Genomic and RNASeq data from the Ericoid Mycorrhizal fungus Oidiodendron maius led to the identification of several symbiosis-upregulated genes encoding putative SSPs. OmSSP1, the most highly symbiosis up-regulated SSP, was found to share some features with fungal hydrophobins, even though it lacks the Pfam hydrophobin domain. Sequence alignment with other hydrophobins and hydrophobin-like fungal proteins placed OmSSP1 within Class I hydrophobins. However, the predicted features of OmSSP1 may suggest a distinct type of hydrophobin-like proteins. The presence of a predicted signal peptide and a yeast-based signal sequence trap assay demonstrate that OmSSP1 is secreted. OmSSP1 null-mutants showed a reduced capacity to form Ericoid Mycorrhiza with Vaccinium myrtillus roots, suggesting a role as effectors in the Ericoid Mycorrhizal interaction.
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Table_4_The Hydrophobin-Like OmSSP1 May Be an Effector in the Ericoid Mycorrhizal Symbiosis.xlsx
2018Co-Authors: Salvatore Casarrubia, Silvia Perotto, Stefania Daghino, Emmanuelle Morin, Hassine Radhouane Khouja, Yohann Daguerre, Claire Veneault-fourrey, Francis M. Martin, Elena MartinoAbstract:Mutualistic and pathogenic plant-colonizing fungi use effector molecules to manipulate the host cell metabolism to allow plant tissue invasion. Some small secreted proteins (SSPs) have been identified as fungal effectors in both ectoMycorrhizal and arbuscular Mycorrhizal fungi, but it is currently unknown whether SSPs also play a role as effectors in other Mycorrhizal associations. Ericoid Mycorrhiza is a specific endoMycorrhizal type that involves symbiotic fungi mostly belonging to the Leotiomycetes (Ascomycetes) and plants in the family Ericaceae. Genomic and RNASeq data from the Ericoid Mycorrhizal fungus Oidiodendron maius led to the identification of several symbiosis-upregulated genes encoding putative SSPs. OmSSP1, the most highly symbiosis up-regulated SSP, was found to share some features with fungal hydrophobins, even though it lacks the Pfam hydrophobin domain. Sequence alignment with other hydrophobins and hydrophobin-like fungal proteins placed OmSSP1 within Class I hydrophobins. However, the predicted features of OmSSP1 may suggest a distinct type of hydrophobin-like proteins. The presence of a predicted signal peptide and a yeast-based signal sequence trap assay demonstrate that OmSSP1 is secreted. OmSSP1 null-mutants showed a reduced capacity to form Ericoid Mycorrhiza with Vaccinium myrtillus roots, suggesting a role as effectors in the Ericoid Mycorrhizal interaction.
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Imaging Mycorrhizal fungal transformants that express EGFP during Ericoid endosymbiosis
Current Genetics, 2007Co-Authors: Elena Martino, Claude Murat, Marta Vallino, Andrea Bena, Silvia Perotto, Pietro SpanuAbstract:Ericoid endoMycorrhizal fungi form intracellular associations with the epidermal root cells of plants belonging to Ericales. In natural environments, these fungi increase the ability of their host plants to colonise soils polluted with toxic metals, although the underlying mechanisms are not clearly understood. Genetic transformation is a powerful tool to study the function of specific genes involved in the interaction of symbiotic fungi with the host plants and with the environment. Here, we investigated the possibility to genetically transform an Ericoid endoMycorrhizal strain. A metal tolerant Mycorrhizal Oidiodendron maius strain isolated from a contaminated area was chosen to develop the transformation system. Two different protocols were used: protoplasts and Agrobacterium -mediated transformation. Stable transformants were obtained with both techniques. They remained competent for Mycorrhizal formation and GFP-transformed fungi were visualised in planta . This is the first report of stable transformation of an Ericoid endoMycorrhizal fungus. The protocol set up could represent a good starting point for the identification of genes important in the Ericoid Mycorrhiza formation and in the understanding of how this symbiosis is established and functions. The success in the genetic transformation of this strain will allow us to better define its potential use in bioremediation strategies.
Marianne Johansson - One of the best experts on this subject based on the ideXlab platform.
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Fungal associations of Danish Calluna vulgaris roots with special reference to Ericoid Mycorrhiza
Plant and Soil, 2001Co-Authors: Marianne JohanssonAbstract:Fungi were isolated from young, serial-washed roots of Calluna sampled from a Danish heathland, Hjelm Hede. Of the 626 isolates, those that were dark, sterile and septate were divided into 13 morphological groups based on their appearance in culture on malt agar. Mycorrhizal synthesis in vitro showed that several groups formed typical Ericoid Mycorrhiza with seedlings of Calluna ; these Ericoid Mycorrhizal fungi were morphologically similar to Hymenoscyphus ericae . The identities of the other dark, septate fungi are uncertain. Oidiodendron spp. were isolated in a very low frequency; these fungi also formed typical Ericoid Mycorrhiza. The Calluna root system on Hjelm Hede demonstrated a high morphological diversity among the associated dark, septate fungi suggesting that more than one fungus could coexist in the same host root system.
Petr Kohout - One of the best experts on this subject based on the ideXlab platform.
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Biogeography of Ericoid Mycorrhiza
Biogeography of Mycorrhizal Symbiosis, 2017Co-Authors: Petr KohoutAbstract:Ericoid Mycorrhiza is a mutualistic relationship between several lineages of plants in the family Ericaceae (Cassiopoideae, Ericoideae, Harrimanelloideae, Styphelioideae, and Vaccinioideae subfamilies) and a diverse group of soil fungi. Compared to the more common Mycorrhizal types such as arbuscular Mycorrhiza and ectoMycorrhiza, Ericoid Mycorrhiza remains largely overlooked, and more detailed understanding of the Ericoid Mycorrhizal symbionts biogeography is lacking. To date, undisputable evidence of Ericoid Mycorrhizal habit has been obtained for only few fungal lineages belonging to Helotiales, Sebacinales, and an undescribed lineage within Agaricomycetes. Ericoid Mycorrhizal symbiosis can be found on all continents, except Antarctica. Although the Ericoid Mycorrhizal plants species richness is the highest in tropical and subtropical regions, they also represent an important vegetation component in temperate and arctic regions. Compared to biogeography of Ericoid Mycorrhizal plants, we have very limited knowledge about the diversity and distribution of Ericoid Mycorrhizal fungi. First insights indicate that the most well-known Ericoid Mycorrhizal fungal species, Rhizoscyphus ericae, has a very broad distribution range. On the contrary, other Ericoid Mycorrhizal fungal species have distribution range restricted to a single hemisphere (Meliniomyces variabilis) or continent (Cairneyella variabilis).
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the potential of dark septate endophytes to form root symbioses with ectoMycorrhizal and Ericoid Mycorrhizal middle european forest plants
PLOS ONE, 2015Co-Authors: Tereza Lukesova, Petr Kohout, Tomas Větrovský, Martin VohníkAbstract: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.
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novel root fungus symbiosis in ericaceae sheathed Ericoid Mycorrhiza formed by a hitherto undescribed basidiomycete with affinities to trechisporales
PLOS ONE, 2012Co-Authors: Martin Vohník, Petr Kohout, Jesse J Sadowsky, Zuzana Lhotakova, Rolf Nestby, Miroslav KolařikAbstract: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.