Mycorrhizal associations of Salix repens L. communities in succession of dune ecosystems. I. Above-ground and below-ground views of ectomycorrhizal fungi in relation to soil chemistry

2000 ◽  
Vol 77 (12) ◽  
pp. 1821-1832 ◽  
Author(s):  
EW van der Heijden ◽  
FW de Vries ◽  
Th. W Kuyper

The diversity of ectomycorrhizal (EcM) communities in 16 stands of Salix repens L. growing under a variety of environmental conditions was studied by repeated sampling of EcM sporocarps and ectomycorrhizas, to assess the possible correspondence between above- and below-ground views of fungal taxa. Above- and below-ground views were also related to soil chemistry. Sporocarps of 78 taxa of EcM fungi belonging to 12 genera were found. The majority of the species found, especially those of the Cortinariaceae, were host-specific for Salicaceae. Canonical correspondence analysis (CCA) based on fungal species showed that only pH and the concentration of available phosphorus significantly contributed to the variation explained. CCA based on fungal genera indicated that pH and moisture significantly contributed to the variation explained. Fifteen different EcM morphotypes were recognized and morphotype composition was different on two sampling dates. CCA based on morphotype composition yielded different results depending on sampling date. The numbers of EcM sporocarps and root tips were not correlated (on either sampling date). Diversity above ground (species and genus) was also not correlated with morphotype diversity below ground on either sampling date. Therefore, neither diversity nor abundance of above-ground EcM fungi can be used to assess below-ground EcM diversity or abundance. Lack of correlation in below-ground parameters on different sampling dates indicates substantial variation. Causes for temporal variation are discussed. The importance of investigating both above- and below-ground variability in EcM communities is stressed.

2014 ◽  
Author(s):  
Peter Kennedy ◽  
Nhu H. Nguyen ◽  
Hannah Cohen ◽  
Kabir G Peay

A number of recent studies suggest that interspecific competition plays a key role in determining the structure of ectomycorrhizal (ECM) fungal communities. Despite this growing consensus, there has been limited study of ECM fungal community dynamics in abiotically stressful environments, which are often dominated by positive rather than antagonistic interactions. In this study, we examined the ECM fungal communities associated with the host genus Alnus, which live in soils high in both nitrate and acidity. The nature of ECM fungal species interactions (i.e. antagonistic, neutral, or positive) was assessed using taxon co-occurrence and sequence abundance correlational analyses. ECM fungal communities were sampled from root tips and mesh in-growth bags in three monodominant A. rubra plots and identified using Illumina-based amplification of the ITS1 gene region. We found a total of 183 ECM fungal taxa present across the plots; 16 of which were closely related to known Alnus-associated ECM fungi. Contrary to previous studies of ECM fungal communities, taxon co-occurrence analyses on both the total and Alnus-associated ECM datasets indicated that the ECM fungal communities in this system were not structured by interspecific competition. Instead the co-occurrence patterns were consistent with either random assembly or significant positive interactions. Pair-wise correlational analyses were also more consistent with neutral or positive interactions. Taken together, our results suggest that interspecific competition does not appear to determine the structure of all ECM fungal communities and that abiotic conditions may be important in determining the specific type of interaction occurring among ECM fungi.


Author(s):  
Adriana Corrales ◽  
Clark L. Ovrebo

ABSTRACTPanamanian montane forests harbor a high diversity of fungi, particularly of ectomycorrhizal (ECM) fungi, however their taxonomy and diversity patterns remain for the most part unexplored. Here we present state of the art fungal taxonomy and diversity patterns at Fortuna Forest Reserve based on morphological and molecular identification of over 1,000 fruiting body collections of macromycetes made over a period of five years. We compare these new results with previously published work based on environmental sampling of Oreomunnea mexicana root tips. We compiled a preliminary list of species and report 22 new genera and 29 new fungal species for Panama. Based on fruiting body collection data we compare the species composition of ECM fungal communities associated with Oreomunnea stands across sites differing in soil fertility and amount of rainfall. We also examine the effect of a long-term nitrogen addition treatment on the fruiting body production of ECM fungi. Finally, we discuss the biogeographic importance of Panama collections which fill in the knowledge gap of ECM fungal records between Costa Rica and Colombia. Given that the isthmus of Panama was an important migration route of ECM tree and fungal species from northern temperate areas to South America, the ECM fungal communities of Panama might show a high degree of isolation and therefore a high level of endemism. We expect that the forests at Fortuna will continue to yield new ECM macromycete data as we continue to study the collected specimens and describe new species.


2014 ◽  
Author(s):  
Peter Kennedy ◽  
Nhu H. Nguyen ◽  
Hannah Cohen ◽  
Kabir G Peay

A number of recent studies suggest that interspecific competition plays a key role in determining the structure of ectomycorrhizal (ECM) fungal communities. Despite this growing consensus, there has been limited study of ECM fungal community dynamics in abiotically stressful environments, which are often dominated by positive rather than antagonistic interactions. In this study, we examined the ECM fungal communities associated with the host genus Alnus, which live in soils high in both nitrate and acidity. The nature of ECM fungal species interactions (i.e. antagonistic, neutral, or positive) was assessed using taxon co-occurrence and sequence abundance correlational analyses. ECM fungal communities were sampled from root tips and mesh in-growth bags in three monodominant A. rubra plots and identified using Illumina-based amplification of the ITS1 gene region. We found a total of 183 ECM fungal taxa present across the plots; 16 of which were closely related to known Alnus-associated ECM fungi. Contrary to previous studies of ECM fungal communities, taxon co-occurrence analyses on both the total and Alnus-associated ECM datasets indicated that the ECM fungal communities in this system were not structured by interspecific competition. Instead the co-occurrence patterns were consistent with either random assembly or significant positive interactions. Pair-wise correlational analyses were also more consistent with neutral or positive interactions. Taken together, our results suggest that interspecific competition does not appear to determine the structure of all ECM fungal communities and that abiotic conditions may be important in determining the specific type of interaction occurring among ECM fungi.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yoriko Sugiyama ◽  
Hirotoshi Sato

Host specificity may potentially limit the distribution expansion of ectomycorrhizal (ECM) fungi into areas where their original host plants are absent. To test this hypothesis, we investigated whether populations of native ECM fungi may establish in stands of exotic host trees, namely those of the Eucalyptus species, in Japan. ECM fungal communities associated with eucalyptus and surrounding native host species (Pinus thunbergii and Fagaceae spp.) were investigated at two sites; one site in which eucalyptus and native trees were growing in isolation, and a second site in which these species were mixed. To identify fungal taxa, the nuclear ribosomal internal transcribed spacer region 1 was sequenced for the ECM fungi from the root tips and clustered into operational taxonomic units (OTUs). To confirm whether the retrieved OTUs were native to Japan, they were queried against the entire database of the National Center for Biotechnology Information, UNITE, and GlobalFungi, whereby sampling locations and associated hosts were obtained from sequences with ≥97% similarity. Eucalyptus trees were associated with seven and 12 ECM fungal OTUs, including putatively exotic OTUs in isolated and mixed sites, respectively. Among the 36 and 63 native ECM fungal OTUs detected from native hosts at isolated and mixed sites, only one OTU was shared with eucalyptus at the respective sites. This means that most native ECM fungi in Japan may be incapable of forming an association with exotic Eucalyptus spp. Notably, even ECM fungi associated with both Pinus and Quercus were not detected from eucalyptus, suggesting that host-fungus incompatibility is determined not only by host phylogenetic relatedness but also by host biogeographic affinities. Our findings show that the incompatibility with eucalyptus as well as dispersal limitation may prevent the distribution expansion of native ECM fungi in Japan into the distribution ranges of Eucalyptus spp., where the original hosts are absent.


Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 279 ◽  
Author(s):  
Thomas E. Marler

Research Highlights: Established stands of Leucaena leucocephala (Lam.) de Wit, Spathodea campanulata P. Beauv., and Vitex parviflora Juss. modified soils in Guam’s limestone forests, reducing storage pools of carbon, nitrogen, and phosphorus. Background and Objectives: Invasive plants may engineer negative changes in ecosystem properties. This study was conducted to determine changes in soil chemistry following infestations of three problematic tree species on Guam. Materials and Methods: Minerals, metals, and mineralization dynamics were measured in invaded sites and paired sites with biodiverse native tree cover. Results: Most soil properties were significantly changed by long-term infestations of the invasive tree species. The soils within invaded sites exhibited total carbon, total nitrogen, and available phosphorus that were less than native sites. In contrast, the carbon/nitrogen ratio increased for every species-site combination. The other chemical properties were idiosyncratic among the sites and species. Conclusions: Mitigation and restoration activities that include the removal of these trees from project sites may require many years for the below-ground ecosystems to return to their native state. These three invasive trees decrease the ability of Guam soils to sequester recalcitrant forms of carbon, nitrogen, and phosphorus.


Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 109 ◽  
Author(s):  
Petra Veselá ◽  
Martina Vašutová ◽  
Magda Edwards-Jonášová ◽  
Pavel Cudlín

Bark beetle infestation is a widespread phenomenon in temperate forests, which are facing significant weather fluctuations accompanying climate change. Fungi play key roles in forest ecosystems as symbionts of ectomycorrhizal trees, decomposers, or parasites, but the effect of severe disturbances on their communities is largely unknown. The responses of soil fungal communities following bark beetle attack were determined using Illumina sequencing of soil samples from 10 microsites in a mature forest not attacked by bark beetle, a forest attacked by bark beetle, a forest destroyed by bark beetle, and a stand where all trees were removed after a windstorm. The proportion of ITS2 sequences assigned to mycorrhizal fungal species decreased with increased intensity of bark beetle attack (from 70 to 15%), whereas the proportion of saprotrophs increased (from 29 to 77%). Differences in the ectomycorrhizal (ECM) fungal community was further characterized by a decrease in the sequence proportion of Elaphomyces sp. and Russula sp. and an increase in Piloderma sp., Wilcoxina sp., and Thelephora terrestris. Interestingly, the species composition of the ECM fungal community in the forest one year after removing the windstorm-damaged trees was similar to that of the mature forest, despite the sequence proportion attributed to ECM fungi decreased.


2015 ◽  
Vol 1 (9) ◽  
pp. e1500291 ◽  
Author(s):  
Hirokazu Toju ◽  
Paulo R. Guimarães ◽  
Jens M. Olesen ◽  
John N. Thompson

In nature, plants and their pollinating and/or seed-dispersing animals form complex interaction networks. The commonly observed pattern of links between specialists and generalists in these networks has been predicted to promote species coexistence. Plants also build highly species-rich mutualistic networks below ground with root-associated fungi, and the structure of these plant–fungus networks may also affect terrestrial community processes. By compiling high-throughput DNA sequencing data sets of the symbiosis of plants and their root-associated fungi from three localities along a latitudinal gradient, we uncovered the entire network architecture of these interactions under contrasting environmental conditions. Each network included more than 30 plant species and hundreds of mycorrhizal and endophytic fungi belonging to diverse phylogenetic groups. The results were consistent with the notion that processes shaping host-plant specialization of fungal species generate a unique linkage pattern that strongly contrasts with the pattern of above-ground plant–partner networks. Specifically, plant–fungus networks lacked a “nested” architecture, which has been considered to promote species coexistence in plant–partner networks. Rather, the below-ground networks had a conspicuous “antinested” topology. Our findings lead to the working hypothesis that terrestrial plant community dynamics are likely determined by the balance between above-ground and below-ground webs of interspecific interactions.


2011 ◽  
Vol 279 (1731) ◽  
pp. 1122-1130 ◽  
Author(s):  
Xiaoke Xing ◽  
Alexander M. Koch ◽  
A. Maxwell P. Jones ◽  
Diane Ragone ◽  
Susan Murch ◽  
...  

During the process of plant domestication, below-ground communities are rarely considered. Some studies have attempted to understand the changes in root symbionts owing to domestication, but little is known about how it influences mycorrhizal response in domesticated crops. We hypothesized that selection for above-ground traits may also result in decreased mycorrhizal abundance in roots. Breadfruit ( Artocarpus sp.) has a long domestication history, with a strong geographical movement of cultivars from west to east across the Melanesian and Polynesian islands. Our results clearly show a decrease in arbuscular mycorrhizas (AMs) along a domestication gradient from wild to recently derived cultivars. We showed that the vesicular and arbuscular colonization rate decreased significantly in more recently derived breadfruit cultivars. In addition, molecular analyses of breadfruit roots indicated that AM fungal species richness also responded along the domestication gradient. These results suggest that human-driven selection for plant cultivars can have unintended effects on below-ground mutualists, with potential impacts on the stress tolerance of crops and long-term food security.


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