The Experts below are selected from a list of 1710 Experts worldwide ranked by ideXlab platform

Lu-min Vaario - One of the best experts on this subject based on the ideXlab platform.

  • formation of mycorrhiza like structures in cultured root callus of cathaya argyrophylla chun et kuang infected with the ectomycorrhizal fungus Cenococcum geophilum fr
    Journal of Integrative Plant Biology, 2006
    Co-Authors: Xue Sun, Lu-min Vaario
    Abstract:

    An in vitro system was used for ectomycorrhizal synthesis of Cenococcum geophilum Fr. with Cathaya argyrophylla Chun et Kuang, an endangered species. Calli initiated from stem segments and adventitious roots differentiated from young seedlings were removed and cocultured with Cenococcum geophilum on a modified Murashige-Skoog medium. Fungal hyphae were visible within intercellular spaces of the callus 4 weeks after inoculation, but definite and well-developed Hartig net structures did not form in the calli 8 weeks after inoculation. The typical ectomycorrhizal structures (i.e. hyphal mantle and intracortical Hartig net) were observed in root segments 8 weeks after inoculation. This is the first report of aseptic ectomycorrhizal-like formation/infection between root organ/callus of Cathaya argyrophylla and the ectomycorrhizal fungus Cenococcum geophilum. This culture system is useful for further investigation of mycorrhizal synthesis in Cathaya trees. (Managing editor: Ya-Qin Han)

  • Formation of Mycorrhiza-like Structures in Cultured Root/Callus of Cathaya argyrophylla Chun et Kuang Infected with the Ectomycorrhizal Fungus Cenococcum geophilum Fr.
    Journal of Integrative Plant Biology, 2006
    Co-Authors: Xue Sun, Lu-min Vaario
    Abstract:

    An in vitro system was used for ectomycorrhizal synthesis of Cenococcum geophilum Fr. with Cathaya argyrophylla Chun et Kuang, an endangered species. Calli initiated from stem segments and adventitious roots differentiated from young seedlings were removed and cocultured with Cenococcum geophilum on a modified Murashige-Skoog medium. Fungal hyphae were visible within intercellular spaces of the callus 4 weeks after inoculation, but definite and well-developed Hartig net structures did not form in the calli 8 weeks after inoculation. The typical ectomycorrhizal structures (i.e. hyphal mantle and intracortical Hartig net) were observed in root segments 8 weeks after inoculation. This is the first report of aseptic ectomycorrhizal-like formation/infection between root organ/callus of Cathaya argyrophylla and the ectomycorrhizal fungus Cenococcum geophilum. This culture system is useful for further investigation of mycorrhizal synthesis in Cathaya trees. (Managing editor: Ya-Qin Han)

  • Aseptic ectomycorrhizal synthesis between Abies firma and Cenococcum geophilum in artificial culture
    Mycoscience, 2000
    Co-Authors: Lu-min Vaario, Warwick M. Gill, Megumi Tanaka, Yuji Ide, Kazuo Suzuki
    Abstract:

    A simple in vitro system is described for the synthesis ofAbies firma-Cenococcum geophilum ectomycorrhizas. SterilizedA. firma seedlings on both MMN and FH media were inoculated with hyphal discs from actively growing margins ofC. geophilum colonies. Typical ectomycorrhizas formed on seedlings on FH medium after 3 mo of incubation. By light microscopy, the synthesized mycorrhizas were seen to possess a thin mantle from which emanated extraradicle hyphae and highly branched, rarely septate intracortical Hartig net mycelium, characteristic ectomycorrhizal features. This is the first report of aseptic ectomycorrhization ofA. firma seedlings byC. geophilum. This model system will facilitate detailed studies on ectomycorrhizal development ofAbies species.

Keisuke Obase - One of the best experts on this subject based on the ideXlab platform.

  • Isolation source matters: sclerotia and ectomycorrhizal roots provide different views of genetic diversity in Cenococcum geophilum
    2018
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    Cenococcum geophilum forms sclerotia and ectomycorrhizas with host plants in forest soils. We demonstrated the differences in genetic diversity of C. geophilum between cultured isolates from sclerotia and those from ectomycorrhizal roots in the same 73 soil samples based on glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene sequences and newly developed microsatellite markers. Based on GAPDH sequences, 759 cultured isolates (553 from sclerotia and 206 from ectomycorrhizas) were classified into 107 “genotypes” with sequence variation of up to 8.6%. The total number of GAPDH genotypes per soil sample ranged from 1 to 9, but genotypes that were shared between sclerotia and ectomycorrhizas were uncommon (0–3 per soil sample). More than 50% of GAPDH genotypes were unique to one source in most soil samples. Unique GAPDH genotypes were detected from either scleotia or ectomycorrhizal roots in most of the soil samples. Multilocus analysis using nine microsatellite markers provided additional resolution to differentiate fungal individuals and supported the results of GAPDH genotyping. The results indicated that sampling both sclerotia and ectomycorrhizal roots maximizes the detection of diversity at the soil core scale. On the other hand, when all isolates were viewed together, 82 GAPDH genotypes were unique to sclerotia whereas only 6 GAPDH genotypes were unique to ectomycorrhizas. Rarefaction analysis indicated that GAPDH genotypic diversity is significantly higher in sclerotia than ectomycorrhizal roots and the diversity within sclerotia is nearly the same as that of both sclerotia and ectomycorrhizas together. These findings suggest that sampling sclerotia alone is likely to detect the majority of GAPDH genotypes in Cenococcum at the regional scale. When deciding whether to sample sclerotia, ectomycorrhizas, or both types of tissues from Cenococcum, it is critical to consider the spatial scale and also the main questions and hypotheses of the study.

  • Progress and Challenges in Understanding the Biology, Diversity, and Biogeography of Cenococcum geophilum
    Biogeography of Mycorrhizal Symbiosis, 2017
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    Cenococcum geophilum (Dothideomycetes, Ascomycota) is one of the most common ectomycorrhizal fungi in boreal and temperate regions. Although C. geophilum was originally considered as a single species, accumulating evidence suggests that C. geophilum is actually a diverse species complex. Here we provide an overview of the current data on global host range, distribution and biogeography of C. geophilum and discuss what is known about the spatial genetic structure at scales from soil cores to biomes to continents. Recent molecular data indicate that the genetic diversity within C. geophilum can be incredibly high, even at the scale of a single soil core. This highlights the need to characterize Cenococcum samples phylogenetically prior to population studies so that cryptic, reproductively isolated species are not admixed together in the analyses. Also sampling design and effort are critical for understanding population and phylogenetic diversity of C. geophilum. A recent population study targeted one Cenococcum lineage in Japanese pine forests and found no spatial autocorrelation at the forest stand level but did find evidence for a pattern of isolation by distance at larger spatial scales. These observations are consistent with the possibility of cryptic recombination. Another recent phylogenetic study found that several Cenococcum lineages are widely distributed across multiple regions and continents. This indicates that some lineages within C. geophilum may be ancient or that cryptic long-distance dispersal is ongoing. Overall, our assessment and review of the recent literature suggests that additional research is needed to understand the population structure and biology of C. geophilum.

  • Revisiting phylogenetic diversity and cryptic species of Cenococcum geophilum sensu lato
    Mycorrhiza, 2016
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    The fungus Cenococcum geophilum Fr. ( Dothideomycetes , Ascomycota ) is one of the most common ectomycorrhizal fungi in boreal to temperate regions. A series of molecular studies has demonstrated that C. geophilum is monophyletic but a heterogeneous species or a species complex. Here, we revisit the phylogenetic diversity of C. geophilum sensu lato from a regional to intercontinental scale by using new data from Florida (USA) along with existing data in GenBank from Japan, Europe, and North America. The combination of internal transcribed spacer (ITS) ribosomal DNA and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene resolved six well-supported lineages (87–100 % bootstrap values) that are closely related to each other and a seventh lineage that is phylogenetically distinct. A multi-locus analysis (small subunit (SSU), large subunit (LSU), translational elongation factor (TEF), and the largest and second-largest subunits of RNA polymerase II (RPB1 and RPB2)) revealed that the divergent lineage is the sister group to all other known Cenococcum isolates. Isolates of the divergent lineage grow fast on nutrient media and do not form ectomycorrhizas on seedlings of several pine and oak species. Our results indicate that C. geophilum sensu lato includes more phylogenetically distinct cryptic species than have previously been reported. Furthermore, the divergent lineage appears to be a non-mycorrhizal sister group. We discuss the phylogenetic diversity of C. geophilum sensu lato and argue in favor of species recognition based on phylogenetic and ecological information in addition to morphological characteristics. A new genus and species ( PseudoCenococcum floridanum gen. et sp. nov.) is proposed to accommodate a divergent and putatively non-mycorrhizal lineage.

  • Culturable fungal assemblages growing within Cenococcum sclerotia in forest soils.
    FEMS microbiology ecology, 2014
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    The ectomycorrhizal fungus Cenococcum geophilum (Ascomycota, Dothideomycetes) forms black, round to irregular sclerotia in forest soils. Fungi that colonize the sclerotia appear to affect sclerotia viability and may play an important role in the life history of Cenococcum. Some of the fungi could also affect nutrient cycling by decomposing Cenococcum sclerotia, which are melanized and recalcitrant to decay. We used a culture-based method to document the fungal communities growing inside surface-sterilized sclerotia that were collected from forest soils. Cenococcum was successfully isolated from 297 of 971 sclerotia whereas 427 sclerotia hosted fungi other than Cenococcum. DNA barcoding of the internal transcribed spacer rDNA followed by grouping at 97% sequence similarity yielded 85 operational taxonomic units (OTUs) that consisted primarily of Ascomycota (e.g. Chaetothyriales, Eurotiales, Helotiales, Pleosporales) and a few Basidiomycota and Mucoromycotina. Although most fungal OTUs were infrequently cultured, several OTUs such as members of Asterostroma, Cladophialophora, Oidiodendron, and Pleosporales were common and found across many sites. Our results suggest that Cenococcum sclerotia act as a substrate for diverse fungi. The occurrence of several OTUs in sclerotia across many sites suggests that these fungi may be active parasites of Cenococcum sclerotia or may preferentially use sclerotia as a nutrient source.

  • Culturable fungal assemblages growing within Cenococcum sclerotia in forest soils
    2014
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    root endophyte; pathogen. The ectomycorrhizal fungus Cenococcum geophilum (Ascomycota, Dothideomyce-tes) forms black, round to irregular sclerotia in forest soils. Fungi that colonize the sclerotia appear to affect sclerotia viability and may play an important role in the life history of Cenococcum. Some of the fungi could also affect nutrient cycling by decomposing Cenococcum sclerotia, which are melanized and recalci-trant to decay. We used a culture-based method to document the fungal com-munities growing inside surface-sterilized sclerotia that were collected from forest soils. Cenococcum was successfully isolated from 297 of 971 sclerotia whereas 427 sclerotia hosted fungi other than Cenococcum. DNA barcoding of the internal transcribed spacer rDNA followed by grouping at 97 % sequence similarity yielded 85 operational taxonomic units (OTUs) that consisted pri-marily of Ascomycota (e.g. Chaetothyriales, Eurotiales, Helotiales, Pleosporales) and a few Basidiomycota and Mucoromycotina. Although most fungal OTUs were infrequently cultured, several OTUs such as members of Asterostroma, Cladophialophora, Oidiodendron, and Pleosporales were common and found across many sites. Our results suggest that Cenococcum sclerotia act as a sub-strate for diverse fungi. The occurrence of several OTUs in sclerotia across many sites suggests that these fungi may be active parasites of Cenococcum sclerotia or may preferentially use sclerotia as a nutrient source

Matthew E. Smith - One of the best experts on this subject based on the ideXlab platform.

  • Isolation source matters: sclerotia and ectomycorrhizal roots provide different views of genetic diversity in Cenococcum geophilum
    2018
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    Cenococcum geophilum forms sclerotia and ectomycorrhizas with host plants in forest soils. We demonstrated the differences in genetic diversity of C. geophilum between cultured isolates from sclerotia and those from ectomycorrhizal roots in the same 73 soil samples based on glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene sequences and newly developed microsatellite markers. Based on GAPDH sequences, 759 cultured isolates (553 from sclerotia and 206 from ectomycorrhizas) were classified into 107 “genotypes” with sequence variation of up to 8.6%. The total number of GAPDH genotypes per soil sample ranged from 1 to 9, but genotypes that were shared between sclerotia and ectomycorrhizas were uncommon (0–3 per soil sample). More than 50% of GAPDH genotypes were unique to one source in most soil samples. Unique GAPDH genotypes were detected from either scleotia or ectomycorrhizal roots in most of the soil samples. Multilocus analysis using nine microsatellite markers provided additional resolution to differentiate fungal individuals and supported the results of GAPDH genotyping. The results indicated that sampling both sclerotia and ectomycorrhizal roots maximizes the detection of diversity at the soil core scale. On the other hand, when all isolates were viewed together, 82 GAPDH genotypes were unique to sclerotia whereas only 6 GAPDH genotypes were unique to ectomycorrhizas. Rarefaction analysis indicated that GAPDH genotypic diversity is significantly higher in sclerotia than ectomycorrhizal roots and the diversity within sclerotia is nearly the same as that of both sclerotia and ectomycorrhizas together. These findings suggest that sampling sclerotia alone is likely to detect the majority of GAPDH genotypes in Cenococcum at the regional scale. When deciding whether to sample sclerotia, ectomycorrhizas, or both types of tissues from Cenococcum, it is critical to consider the spatial scale and also the main questions and hypotheses of the study.

  • Progress and Challenges in Understanding the Biology, Diversity, and Biogeography of Cenococcum geophilum
    Biogeography of Mycorrhizal Symbiosis, 2017
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    Cenococcum geophilum (Dothideomycetes, Ascomycota) is one of the most common ectomycorrhizal fungi in boreal and temperate regions. Although C. geophilum was originally considered as a single species, accumulating evidence suggests that C. geophilum is actually a diverse species complex. Here we provide an overview of the current data on global host range, distribution and biogeography of C. geophilum and discuss what is known about the spatial genetic structure at scales from soil cores to biomes to continents. Recent molecular data indicate that the genetic diversity within C. geophilum can be incredibly high, even at the scale of a single soil core. This highlights the need to characterize Cenococcum samples phylogenetically prior to population studies so that cryptic, reproductively isolated species are not admixed together in the analyses. Also sampling design and effort are critical for understanding population and phylogenetic diversity of C. geophilum. A recent population study targeted one Cenococcum lineage in Japanese pine forests and found no spatial autocorrelation at the forest stand level but did find evidence for a pattern of isolation by distance at larger spatial scales. These observations are consistent with the possibility of cryptic recombination. Another recent phylogenetic study found that several Cenococcum lineages are widely distributed across multiple regions and continents. This indicates that some lineages within C. geophilum may be ancient or that cryptic long-distance dispersal is ongoing. Overall, our assessment and review of the recent literature suggests that additional research is needed to understand the population structure and biology of C. geophilum.

  • Revisiting phylogenetic diversity and cryptic species of Cenococcum geophilum sensu lato
    Mycorrhiza, 2016
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    The fungus Cenococcum geophilum Fr. ( Dothideomycetes , Ascomycota ) is one of the most common ectomycorrhizal fungi in boreal to temperate regions. A series of molecular studies has demonstrated that C. geophilum is monophyletic but a heterogeneous species or a species complex. Here, we revisit the phylogenetic diversity of C. geophilum sensu lato from a regional to intercontinental scale by using new data from Florida (USA) along with existing data in GenBank from Japan, Europe, and North America. The combination of internal transcribed spacer (ITS) ribosomal DNA and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene resolved six well-supported lineages (87–100 % bootstrap values) that are closely related to each other and a seventh lineage that is phylogenetically distinct. A multi-locus analysis (small subunit (SSU), large subunit (LSU), translational elongation factor (TEF), and the largest and second-largest subunits of RNA polymerase II (RPB1 and RPB2)) revealed that the divergent lineage is the sister group to all other known Cenococcum isolates. Isolates of the divergent lineage grow fast on nutrient media and do not form ectomycorrhizas on seedlings of several pine and oak species. Our results indicate that C. geophilum sensu lato includes more phylogenetically distinct cryptic species than have previously been reported. Furthermore, the divergent lineage appears to be a non-mycorrhizal sister group. We discuss the phylogenetic diversity of C. geophilum sensu lato and argue in favor of species recognition based on phylogenetic and ecological information in addition to morphological characteristics. A new genus and species ( PseudoCenococcum floridanum gen. et sp. nov.) is proposed to accommodate a divergent and putatively non-mycorrhizal lineage.

  • Culturable fungal assemblages growing within Cenococcum sclerotia in forest soils.
    FEMS microbiology ecology, 2014
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    The ectomycorrhizal fungus Cenococcum geophilum (Ascomycota, Dothideomycetes) forms black, round to irregular sclerotia in forest soils. Fungi that colonize the sclerotia appear to affect sclerotia viability and may play an important role in the life history of Cenococcum. Some of the fungi could also affect nutrient cycling by decomposing Cenococcum sclerotia, which are melanized and recalcitrant to decay. We used a culture-based method to document the fungal communities growing inside surface-sterilized sclerotia that were collected from forest soils. Cenococcum was successfully isolated from 297 of 971 sclerotia whereas 427 sclerotia hosted fungi other than Cenococcum. DNA barcoding of the internal transcribed spacer rDNA followed by grouping at 97% sequence similarity yielded 85 operational taxonomic units (OTUs) that consisted primarily of Ascomycota (e.g. Chaetothyriales, Eurotiales, Helotiales, Pleosporales) and a few Basidiomycota and Mucoromycotina. Although most fungal OTUs were infrequently cultured, several OTUs such as members of Asterostroma, Cladophialophora, Oidiodendron, and Pleosporales were common and found across many sites. Our results suggest that Cenococcum sclerotia act as a substrate for diverse fungi. The occurrence of several OTUs in sclerotia across many sites suggests that these fungi may be active parasites of Cenococcum sclerotia or may preferentially use sclerotia as a nutrient source.

  • Culturable fungal assemblages growing within Cenococcum sclerotia in forest soils
    2014
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    root endophyte; pathogen. The ectomycorrhizal fungus Cenococcum geophilum (Ascomycota, Dothideomyce-tes) forms black, round to irregular sclerotia in forest soils. Fungi that colonize the sclerotia appear to affect sclerotia viability and may play an important role in the life history of Cenococcum. Some of the fungi could also affect nutrient cycling by decomposing Cenococcum sclerotia, which are melanized and recalci-trant to decay. We used a culture-based method to document the fungal com-munities growing inside surface-sterilized sclerotia that were collected from forest soils. Cenococcum was successfully isolated from 297 of 971 sclerotia whereas 427 sclerotia hosted fungi other than Cenococcum. DNA barcoding of the internal transcribed spacer rDNA followed by grouping at 97 % sequence similarity yielded 85 operational taxonomic units (OTUs) that consisted pri-marily of Ascomycota (e.g. Chaetothyriales, Eurotiales, Helotiales, Pleosporales) and a few Basidiomycota and Mucoromycotina. Although most fungal OTUs were infrequently cultured, several OTUs such as members of Asterostroma, Cladophialophora, Oidiodendron, and Pleosporales were common and found across many sites. Our results suggest that Cenococcum sclerotia act as a sub-strate for diverse fungi. The occurrence of several OTUs in sclerotia across many sites suggests that these fungi may be active parasites of Cenococcum sclerotia or may preferentially use sclerotia as a nutrient source

Greg W. Douhan - One of the best experts on this subject based on the ideXlab platform.

  • Isolation source matters: sclerotia and ectomycorrhizal roots provide different views of genetic diversity in Cenococcum geophilum
    2018
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    Cenococcum geophilum forms sclerotia and ectomycorrhizas with host plants in forest soils. We demonstrated the differences in genetic diversity of C. geophilum between cultured isolates from sclerotia and those from ectomycorrhizal roots in the same 73 soil samples based on glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene sequences and newly developed microsatellite markers. Based on GAPDH sequences, 759 cultured isolates (553 from sclerotia and 206 from ectomycorrhizas) were classified into 107 “genotypes” with sequence variation of up to 8.6%. The total number of GAPDH genotypes per soil sample ranged from 1 to 9, but genotypes that were shared between sclerotia and ectomycorrhizas were uncommon (0–3 per soil sample). More than 50% of GAPDH genotypes were unique to one source in most soil samples. Unique GAPDH genotypes were detected from either scleotia or ectomycorrhizal roots in most of the soil samples. Multilocus analysis using nine microsatellite markers provided additional resolution to differentiate fungal individuals and supported the results of GAPDH genotyping. The results indicated that sampling both sclerotia and ectomycorrhizal roots maximizes the detection of diversity at the soil core scale. On the other hand, when all isolates were viewed together, 82 GAPDH genotypes were unique to sclerotia whereas only 6 GAPDH genotypes were unique to ectomycorrhizas. Rarefaction analysis indicated that GAPDH genotypic diversity is significantly higher in sclerotia than ectomycorrhizal roots and the diversity within sclerotia is nearly the same as that of both sclerotia and ectomycorrhizas together. These findings suggest that sampling sclerotia alone is likely to detect the majority of GAPDH genotypes in Cenococcum at the regional scale. When deciding whether to sample sclerotia, ectomycorrhizas, or both types of tissues from Cenococcum, it is critical to consider the spatial scale and also the main questions and hypotheses of the study.

  • Progress and Challenges in Understanding the Biology, Diversity, and Biogeography of Cenococcum geophilum
    Biogeography of Mycorrhizal Symbiosis, 2017
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    Cenococcum geophilum (Dothideomycetes, Ascomycota) is one of the most common ectomycorrhizal fungi in boreal and temperate regions. Although C. geophilum was originally considered as a single species, accumulating evidence suggests that C. geophilum is actually a diverse species complex. Here we provide an overview of the current data on global host range, distribution and biogeography of C. geophilum and discuss what is known about the spatial genetic structure at scales from soil cores to biomes to continents. Recent molecular data indicate that the genetic diversity within C. geophilum can be incredibly high, even at the scale of a single soil core. This highlights the need to characterize Cenococcum samples phylogenetically prior to population studies so that cryptic, reproductively isolated species are not admixed together in the analyses. Also sampling design and effort are critical for understanding population and phylogenetic diversity of C. geophilum. A recent population study targeted one Cenococcum lineage in Japanese pine forests and found no spatial autocorrelation at the forest stand level but did find evidence for a pattern of isolation by distance at larger spatial scales. These observations are consistent with the possibility of cryptic recombination. Another recent phylogenetic study found that several Cenococcum lineages are widely distributed across multiple regions and continents. This indicates that some lineages within C. geophilum may be ancient or that cryptic long-distance dispersal is ongoing. Overall, our assessment and review of the recent literature suggests that additional research is needed to understand the population structure and biology of C. geophilum.

  • Revisiting phylogenetic diversity and cryptic species of Cenococcum geophilum sensu lato
    Mycorrhiza, 2016
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    The fungus Cenococcum geophilum Fr. ( Dothideomycetes , Ascomycota ) is one of the most common ectomycorrhizal fungi in boreal to temperate regions. A series of molecular studies has demonstrated that C. geophilum is monophyletic but a heterogeneous species or a species complex. Here, we revisit the phylogenetic diversity of C. geophilum sensu lato from a regional to intercontinental scale by using new data from Florida (USA) along with existing data in GenBank from Japan, Europe, and North America. The combination of internal transcribed spacer (ITS) ribosomal DNA and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene resolved six well-supported lineages (87–100 % bootstrap values) that are closely related to each other and a seventh lineage that is phylogenetically distinct. A multi-locus analysis (small subunit (SSU), large subunit (LSU), translational elongation factor (TEF), and the largest and second-largest subunits of RNA polymerase II (RPB1 and RPB2)) revealed that the divergent lineage is the sister group to all other known Cenococcum isolates. Isolates of the divergent lineage grow fast on nutrient media and do not form ectomycorrhizas on seedlings of several pine and oak species. Our results indicate that C. geophilum sensu lato includes more phylogenetically distinct cryptic species than have previously been reported. Furthermore, the divergent lineage appears to be a non-mycorrhizal sister group. We discuss the phylogenetic diversity of C. geophilum sensu lato and argue in favor of species recognition based on phylogenetic and ecological information in addition to morphological characteristics. A new genus and species ( PseudoCenococcum floridanum gen. et sp. nov.) is proposed to accommodate a divergent and putatively non-mycorrhizal lineage.

  • Culturable fungal assemblages growing within Cenococcum sclerotia in forest soils.
    FEMS microbiology ecology, 2014
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    The ectomycorrhizal fungus Cenococcum geophilum (Ascomycota, Dothideomycetes) forms black, round to irregular sclerotia in forest soils. Fungi that colonize the sclerotia appear to affect sclerotia viability and may play an important role in the life history of Cenococcum. Some of the fungi could also affect nutrient cycling by decomposing Cenococcum sclerotia, which are melanized and recalcitrant to decay. We used a culture-based method to document the fungal communities growing inside surface-sterilized sclerotia that were collected from forest soils. Cenococcum was successfully isolated from 297 of 971 sclerotia whereas 427 sclerotia hosted fungi other than Cenococcum. DNA barcoding of the internal transcribed spacer rDNA followed by grouping at 97% sequence similarity yielded 85 operational taxonomic units (OTUs) that consisted primarily of Ascomycota (e.g. Chaetothyriales, Eurotiales, Helotiales, Pleosporales) and a few Basidiomycota and Mucoromycotina. Although most fungal OTUs were infrequently cultured, several OTUs such as members of Asterostroma, Cladophialophora, Oidiodendron, and Pleosporales were common and found across many sites. Our results suggest that Cenococcum sclerotia act as a substrate for diverse fungi. The occurrence of several OTUs in sclerotia across many sites suggests that these fungi may be active parasites of Cenococcum sclerotia or may preferentially use sclerotia as a nutrient source.

  • Culturable fungal assemblages growing within Cenococcum sclerotia in forest soils
    2014
    Co-Authors: Keisuke Obase, Yosuke Matsuda, Greg W. Douhan, Matthew E. Smith
    Abstract:

    root endophyte; pathogen. The ectomycorrhizal fungus Cenococcum geophilum (Ascomycota, Dothideomyce-tes) forms black, round to irregular sclerotia in forest soils. Fungi that colonize the sclerotia appear to affect sclerotia viability and may play an important role in the life history of Cenococcum. Some of the fungi could also affect nutrient cycling by decomposing Cenococcum sclerotia, which are melanized and recalci-trant to decay. We used a culture-based method to document the fungal com-munities growing inside surface-sterilized sclerotia that were collected from forest soils. Cenococcum was successfully isolated from 297 of 971 sclerotia whereas 427 sclerotia hosted fungi other than Cenococcum. DNA barcoding of the internal transcribed spacer rDNA followed by grouping at 97 % sequence similarity yielded 85 operational taxonomic units (OTUs) that consisted pri-marily of Ascomycota (e.g. Chaetothyriales, Eurotiales, Helotiales, Pleosporales) and a few Basidiomycota and Mucoromycotina. Although most fungal OTUs were infrequently cultured, several OTUs such as members of Asterostroma, Cladophialophora, Oidiodendron, and Pleosporales were common and found across many sites. Our results suggest that Cenococcum sclerotia act as a sub-strate for diverse fungi. The occurrence of several OTUs in sclerotia across many sites suggests that these fungi may be active parasites of Cenococcum sclerotia or may preferentially use sclerotia as a nutrient source

Jonathan R Cumming - One of the best experts on this subject based on the ideXlab platform.

  • diversity of Cenococcum geophilum isolates from serpentine and non serpentine soils
    Mycologia, 2001
    Co-Authors: Daniel G Panaccione, Nancy L Sheets, Susan P Miller, Jonathan R Cumming
    Abstract:

    Serpentine soils are characterized by a dis- proportionate level of Mg in relation to Ca and often contain phytotoxic levels of available Ni. Both of these factors may represent stresses to plants and fun- gi colonizing these soils. Ectomycorrhizal fungi play important roles in tree biology, and ecotypic adap- tation in these fungi may be critical to the success of trees on serpentine soils. A collection of Cenococcum geophilum isolates was obtained from serpentine and non-serpentine soils by trapping isolates on the roots of Virginia pine (Pinus virginiana) seedlings. Restric- tion fragment length polymorphism (RFLP) analysis of the internal transcribed spacer region of ribosom- al repeat exhibited certain common fragments among isolates and other fragments that varied in length. Additional polymorphic markers were ob- tained from PCR-amplified (3-tubulin gene fragments. UPGMA analysis of the RFLP data indicated that, with one possible exception, the serpentine isolates of C. geophilum are genetically more similar to each other than they are to the isolates from local or dis- tant non-serpentine sites. AFLP analyses, sampling a greater number of loci across the genome, provided an even more distinct separation of the serpentine isolates from non-serpentine isolates. All serpentine isolates lacked a group I intron frequently found within the 18S ribosomal RNA gene in isolates of this species. The genetic divergence between serpentine and non-serpentine isolates may reflect adaptation to