Belowground Fungal Communities Research Articles

Impact of Invasive Ageratina adenophora on Soil Fungi in Native Plant-Grown Soils in Nepal

Invasion of alien plants impacts both the above- and below-ground communities. The specific response of soil microbes to alien plants may depend upon the presence of native inhabitants and the origin of the byproducts released from different parts of invasive plants. This study evaluated the response of common soil fungi against Ageratina adenophora byproducts (extracts) in the presence of two native shrubs, Elsholtzia blanda and Osbeckia stellata, in Nepal. A total of eight fungal species were isolated from soils where these two native species were grown separately, and the occurrence of the fungi was evaluated. The occurrence and frequency of fungus species varied with extracts of A. adenophora leaves, litter and roots as well as with the presence of specific native plants. Particularly, A. adenophora further inhibits the fungi that are naturally less frequent in soil, like Hormodendrum sp. and fresh leaves and litter of A. adenophora were responsible for inhibiting antagonistic fungi like Trichoderma harzianum. Influence in below-ground fungal communities by A. adenophora is one of the reasons for poor growth and development of native seedlings and the mechanism could be a strategy of invasion of A. adenohora in novel areas.

Diversity and Composition of Belowground Fungal Communities Associated with Picea abies L. (H.) Karst. and Larix sp. Mill.: A Comparative Study

The aim of the presented study was to compare the diversity and composition of fungal communities associated with the roots and the rhizosphere soil of P. abies and Larix sp. in mid-age and mature managed forest stands in Lithuania. We also aimed to assess the presence of fungi–host-specific associations, i.e., whether Larix sp. stands could provide habitats for soil fungi currently associated with P. abies. The study sites were 10 Larix sp. and 10 P. abies forest stands in Lithuania. For the study, 100 root samples and 10 organic and 10 mineral soil samples were collected in P. abies stands as well as the same number in Larix sp. stands, and DNA was isolated, amplified using ITS2 rDNA as a marker and subjected to high-throughput sequencing. The results showed that the Shannon diversity index of fungal communities was similar between the two tree species when compared either between root (H = 4.26 P. abies and H = 3.82 Larix sp.), organic soil (H = 5.12 P. abies and H = 5.13 Larix sp.) or mineral soil (H = 4.71 P. abies and H = 4.29 Larix sp.) samples. Multivariate analysis showed that the fungal community composition in the organic and mineral soil samples of both P. abies and Larix sp. were similar, and thus, overlapping. The analysis also showed that the distribution of fungal species was denser in the roots and organic soil but more scattered in mineral soil. However, several fungi in the roots of either P. abies or Larix sp. showed a certain host specificity.

High diversity of fungal ecological groups in Andean-Patagonian Nothofagus forests.

Native Andean-Patagonian Nothofagus forests harbour a unique diversity of microorganisms with diverse ecological roles. Although ectomycorrhizal associations constitute an important fragment of the biota associated with these forests, the factors affecting such communities are largely unknown. We investigated the biodiversity, relative abundance, and composition of ectomycorrhizal fungal communities in relation to two host tree species and ages and the soil properties in six monospecific and mixed evergreen-deciduous Nothofagus forests. We used the internal transcribed spacer (ITS2) region by sequencing 9,600 ectomycorrhizae (ECM) root tips for the identification of fungi. In total, 1,125 fungal taxa at the genus level distributed over 131 orders were identified. The phyla Ascomycota (34.5%) and Basidiomycota (62.1%) were the most abundant, whereas Mucoromycota (3.1%), Chytridiomycota, Cryptomycota, Olpidiomycota, and Zoopagomycota occurred less frequently. The highest taxon diversity was found in old trees, whereas young trees often exhibited a lower diversity of the associated fungi. The fungal taxa were grouped into seven broad ecological categories, of which saprotrophic associations were most common, followed by pathotrophic, pathotrophic-saprotrophic-symbiotrophic, pathotrophic-saprotrophic, and symbiotrophic associations. We did not detect significant differences in the number of taxa in each category between young and old N. dombeyi and N. obliqua. Overall, the scale of the Illumina sequencing approach allowed us to detect a fungal taxa diversity that would not be possible to find through surveys of fruiting bodies alone and that have never been observed in Nothofagus forests before. Our findings suggest the impact of the proximity between sites, the similarity of the soil conditions, and anthropogenic use of the forests on the belowground fungal community's diversity and composition. Furthermore, there were differences between above- and belowground occurrences of the edible mushrooms B. loyo and Ramaria spp. However, future research, including on EMC tips found beneath fairy rings could provide significantly better correlations with the occurrence of aboveground fruiting body.

Mycorrhiza Better Predict Soil Fungal Community Composition and Function than Aboveground Traits in Temperate Forest Ecosystems

Forests in the northeastern US are experiencing shifts in community composition due to the northward migration of warm-adapted tree species and certain species’ declines (for example, white ash and eastern hemlock) due to invasive insects. Changes in belowground fungal communities and associated functions will inevitably follow. Therefore, we sought to investigate the relative importance of two important tree characteristics—mycorrhizal type [ectomycorrhizal (EcM) or arbuscular mycorrhizal (AM)] and leaf habit (deciduous or evergreen) on soil fungal community composition and organic matter cycling. We sampled soil in the organic and mineral horizons beneath two AM-associated (Fraxinus americana and Thuja occidentalis) and two ECM-associated tree species (Betula alleghaniensis and Tsuga canadensis), with an evergreen and deciduous species in each mycorrhizal group. To characterize fungal communities and organic matter decomposition beneath each tree species, we sequenced the ITS1 region of fungal DNA and measured the potential activity of carbon- and nitrogen-targeting extracellular enzymes. Each tree species harbored distinct fungal communities, supporting the need to consider both mycorrhizal type and leaf habit. However, between tree characteristics, mycorrhizal type better predicted fungal communities. Across fungal guilds, saprotrophic fungi were the most important group in shaping fungal community differences in soils beneath all tree species. The effect of leaf habit on carbon- and nitrogen-targeting hydrolytic enzymes depended on tree mycorrhizal association in the organic horizon, while oxidative enzyme activities were higher beneath EcM-associated trees across both soil horizons and leaf habits.

Belowground microbiota analysis indicates that Fusarium spp. exacerbate grapevine trunk disease

BackgroundGrapevine trunk diseases (GTDs) are disease complexes that are major threats to viticulture in most grapevine growing regions. The microbiomes colonizing plant belowground components form complex associations with plants, play important roles in promoting plant productivity and health in natural environments, and may be related to GTD development. To investigate associations between belowground fungal communities and GTD symptomatic or asymptomatic grapevines, fungal communities associated with three soil–plant compartments (bulk soils, rhizospheres, and roots) were characterized by ITS high-throughput amplicon sequencing across two years.ResultsThe fungal community diversity and composition differs according to the soil–plant compartment type (PERMANOVA, p < 0.001, 12.04% of variation explained) and sampling year (PERMANOVA, p < 0.001, 8.83%), whereas GTD symptomatology exhibited a weaker, but still significant association (PERMANOVA, p < 0.001, 1.29%). The effects of the latter were particularly prominent in root and rhizosphere community comparisons. Many GTD-associated pathogens were detected, but their relative abundances were not correlated (or were negatively correlated) to symptomatology. Fusarium spp., were enriched in symptomatic roots and rhizospheres compared to asymptomatic counterparts, suggesting that their abundances were positively correlated with symptomatic vines. Inoculation tests revealed that Fusarium isolates, similar to Dactylonectria macrodidyma, a pathogen associated with black foot disease, caused dark brown necrotic spots on stems in addition to root rot, which blackened lateral roots. Disease indices were higher with co-inoculation than single inoculation with a Fusarium isolate or D. macrodidyma, suggesting that Fusarium spp. can exacerbate disease severity when inoculated with other known GTD-associated pathogens.ConclusionsThe belowground fungal microbiota of grapevines varied from soil–plant compartments, the years and whether showed GTD symptoms. The GTDs symptoms were related to the enrichment of Fusarium spp. rather than the relative abundances of GTD pathogens. These results demonstrate the effects of fungal microbiota of roots and rhizospheres on GTDs, while providing new insights into opportunistic pathogenesis of GTDs and potential control practices.

Habitat and tree species identity shape aboveground and belowground fungal communities in central European forests.

Trees interact with fungi in mutualistic, saprotrophic, and pathogenic relationships. With their extensive aboveground and belowground structures, trees provide diverse habitats for fungi. Thus, tree species identity is an important driver of fungal community composition in forests. Here we investigate how forest habitat (bark surface vs. soil) and tree species identity (deciduous vs. coniferous) affect fungal communities in two Central European forests. We assess differences and interactions between fungal communities associated with bark surfaces and soil, in forest plots dominated either by Fagus sylvatica, Picea abies, or Pinus sylvestris in two study regions in southwestern and northeastern Germany. ITS metabarcoding yielded 3,357 fungal amplicon sequence variants (ASVs) in the northern and 6,088 in the southern region. Overall, soil communities were 4.7 times more diverse than bark communities. Habitat type explained 48-69% of the variation in alpha diversity, while tree species identity explained >1-3%. NMDS ordinations showed that habitat type and host tree species structured the fungal communities. Overall, few fungal taxa were shared between habitats, or between tree species, but the shared taxa were highly abundant. Network analyses, based on co-occurrence patterns, indicate that aboveground and belowground communities form distinct subnetworks. Our study suggests that habitat (bark versus soil) and tree species identity are important factors structuring fungal communities in temperate European forests. The aboveground (bark-associated) fungal community is currently poorly known, including a high proportion of reads assigned to "unknown Ascomycota" or "unknown Dothideomycetes." The role of bark as a habitat and reservoir of unique fungal diversity in forests has been underestimated.

Large-diameter trees and deadwood correspond with belowground ectomycorrhizal fungal richness

BackgroundLarge-diameter trees have an outsized influence on aboveground forest dynamics, composition, and structure. Although their influence on aboveground processes is well studied, their role in shaping belowground fungal communities is largely unknown. We sought to test if (i) fungal community spatial structure matched aboveground forest structure; (ii) fungal functional guilds exhibited differential associations to aboveground trees, snags, and deadwood; and (iii) that large-diameter trees and snags have a larger influence on fungal community richness than smaller-diameter trees. We used MiSeq sequencing of fungal communities collected from soils in a spatially intensive survey in a portion of Cedar Breaks National Monument, Utah, USA. We used random forest models to explore the spatial structure of fungal communities as they relate to explicitly mapped trees and deadwood distributed across 1.15 ha of a 15.32-ha mapped subalpine forest.ResultsWe found 6,177 fungal amplicon sequence variants across 117 sequenced samples. Tree diameter, deadwood presence, and tree species identity explained more than twice as much variation (38.7% vs. 10.4%) for ectomycorrhizal composition and diversity than for the total or saprotrophic fungal communities. Species identity and distance to the nearest large-diameter tree (≥ 40.2 cm) were better predictors of fungal richness than were the identity and distance to the nearest tree. Soil nutrients, topography, and tree species differentially influenced the composition and diversity of each fungal guild. Locally rare tree species had an outsized influence on fungal community richness.ConclusionsThese results highlight that fungal guilds are differentially associated with the location, size, and species of aboveground trees. Large-diameter trees are implicated as drivers of belowground fungal diversity, particularly for ectomycorrhizal fungi.

Phosphorus and Zinc Are Strongly Associated with Belowground Fungal Communities in Wheat Field under Long-Term Fertilization.

ABSTRACTBelowground fungi are closely related to crop growth, and agricultural fertilization is widely known to affect soil fungal communities. Yet it remains unclear whether fungal communities in differing belowground habitats—root endosphere, rhizosphere soil, and bulk soil—respond differently to long-term fertilization. Here we investigated the variation in fungal communities of root endosphere, rhizosphere soil, and bulk soil under 35 years of fertilization in wheat fields. Specifically, the fertilization regimes were applied as five treatments: soils receiving NPK fertilizer, NPK and cow manure (NPK+CM), NPK and pig manure (NPK+PM), NPK and wheat straw (NPK+WS), and no fertilizer (Control). Long-term fertilization significantly impacted fungal community composition in all three habitats, and these effects were stronger in the rhizosphere and bulk soils than root endosphere. Mantel test results showed that fungal community composition was significantly correlated with phosphorus and zinc contents. Further, fungal alpha diversity was lowest in the NPK+PM treatment and was negatively correlated with both phosphorus and zinc contents. Moreover, NPK+PM treatment had the lowest complexity of fungal co-occurrence network, and in general network complexity was significantly negatively correlated with the zinc and phosphorus contents. Taken together, these results suggest that long-term fertilization can impact fungal communities not only in soils but in root endosphere, and this is strongly associated with the contents of phosphorus and zinc there, a finding important for guiding fertilization management practices and supporting sustainable agriculture.IMPORTANCE Fungi, an essential component in nutrient cycling and plant growth, are highly sensitive to fertilization. However, there are limited studies on fungi in root endosphere under long-term fertilization management. Our research extended the study on the endophytic fungal community of crop roots under agricultural management and found that its responses were similar to the communities in soil habitats. In addition, the type of organic materials was reported as the main driver affecting soil fungal community under long-term fertilization. Our research further revealed that the underlying mechanism of affecting the fungal communities in the soils and roots was the differences in phosphorus and zinc contents caused by the application of different organic materials. Therefore, our results highlight that except for phosphorus, zinc content of the organic materials should be considered in long-term organic fertilization systems.

Root-associated fungal community reflects host spatial co-occurrence patterns in a subtropical forest

Plant roots harbor and interact with diverse fungal species. By changing these belowground fungal communities, focal plants can affect the performance of surrounding individuals and the outcome of coexistence. Although highly host related, the roles of these root-associated fungal communities per se in host plant spatial co-occurrence is largely unknown. Here, we evaluated the host dependency of root-associated communities for 39-plant species spatially mapped throughout a 50-ha subtropical forest plot with relevant environmental properties. In addition, we explored whether the differentiation in root fungal associations among plant species can reflect their observed co-occurrence patterns. We demonstrated a strong host-dependency by discriminating the differentiation of root-associated fungal communities regardless of background soil heterogeneity. Furthermore, Random Forest modeling indicated that these nonrandom root fungal associations significantly increased our ability to explain spatial co-occurrence patterns, and to a greater degree than the relative abundance, phylogenetic relatedness, and functional traits of the host plants. Our results further suggested that plants harbor more abundant shared, “generalist” pathogens are likely segregated, while hosting more abundant unique, “specialist” ectomycorrhizal fungi might be an important strategy for promoting spatial aggregation, particularly between early established trees and the heterospecific adults. Together, we provide a conceptual and testable approach to integrate this host-dependent root fungal “fingerprinting” into the plant diversity patterns. We highlight that this approach is complementary to the classic cultivation-based scheme and can deepen our understanding of the community-level effect from overall fungi and its contribution to the pairwise plant dynamics in local species-rich communities.

Spheres of Influence: Host Tree Proximity and Soil Chemistry Shape rRNA, but Not DNA, Communities of Symbiotic and Free-Living Soil Fungi in a Mixed Hardwood-Conifer Forest

Host and symbiont diversity are inextricably linked across partnerships and ecosystems, with degree of partner reliance governing the strength of this correlation. In many forest soils, symbiotic ectomycorrhizal fungi coexist and compete with free-living saprotrophic fungi, with the outcomes of these interactions shaping resource availability and competitive outcomes for the trees aboveground. Traditional approaches to characterizing these communities rely on DNA sequencing of a ribosomal precursor RNA gene (the internal transcribed spacer region), but directly sequencing the precursor rRNA may provide a more functionally relevant perspective on the potentially active fungal communities. Here, we map ectomycorrhizal and saprotrophic soil fungal communities through a mixed hardwood-conifer forest to assess how above- and belowground diversity linkages compare across these differently adapted guilds. Using highly spatially resolved transects (sampled every 2 m) and well-mapped stands of varying host tree diversity, we sought to understand the relative influence of symbiosis versus environment in predicting fungal diversity measures. Canopy species in this forest included two oaks (Quercus agrifoliaandQuercus douglasii) and one pine (Pinus sabiniana). At the scale of our study, spatial turnover in rRNA-based communities was much more predictable from measurable environmental attributes than DNA-based communities. And while turnover of ectomycorrhizal fungi and saprotrophs were predictable by the presence and abundance of different canopy species, they both responded strongly to soil nutrient characteristics, namely pH and nitrogen availability, highlighting the niche overlap of these coexisting guilds and the strong influence of aboveground plants on belowground fungal communities.

Establishment of spruce plantations in native birch forests reduces soil fungal diversity.

ABSTRACTPlantations of Norway spruce have been established well beyond its natural range in many parts of the world, potentially impacting native microbial ecosystems and the processes they mediate. In this study, we investigate how the establishment of spruce plantations in a landscape dominated by native birch forests in western Norway impacts soil properties and belowground fungal communities. Soil cores were collected from neighboring stands of planted spruce and native birch forests. We used DNA metabarcoding of the rDNA internal transcribed spacer 2 region and ergosterol measurements to survey the fungal community composition and its biomass, respectively. In the two investigated soil layers (litter and humus), fungal community composition, diversity and biomass were strongly affected by the tree species shift. Native birch stands hosted markedly richer fungal communities, including numerous fungi not present in planted spruce stands. In contrast, the spruce stands included higher relative abundance of ectomycorrhizal fungi as well as higher fungal biomass. Hence, establishing plantations of Norway spruce in native birch forests leads to significant losses in diversity, but increase in biomass of ectomycorrhizal fungi, which could potentially impact carbon sequestration processes and ecosystem functioning.

Divergent, age-associated fungal communities of Pinus flexilis and Pinus longaeva

The long-lived five-needle pines, Pinus flexilis (limber pine) and Pinus longaeva (Great Basin bristlecone pine) can co-occur and may form symbiotic partnerships with the same species of ectomycorrhizal fungi. These shared symbiotic relationships may facilitate the persistence of these pine species. Throughout their lives, P. flexilis and P. longaeva may also assemble unique belowground fungal communities, adding to the conservation value of ancient trees. We used MiSeq sequencing of fungal rDNA to compare fungal community similarity for co-occurring P. flexilis and P. longaeva roots and soils in an old-growth forest at the Utah Forest Dynamics Plot, Utah, USA. We cored trees to measure their age and determine whether fungal communities change with advanced tree age. We found 720 amplicon sequence variants associated with P. flexilis roots, 736 with P. longaeva roots, and 199 that were shared between the two pines. Root-associated fungal communities were significantly different between P. flexilis and P. longaeva despite similar soil communities. The fungal community composition on P. flexilis roots and around P. longaeva soil was associated with advanced tree age up to 1340 years. The root-associated fungal community of P. flexilis and the soil community of P. longaeva increased in dissimilarity with tree age, indicating that age heterogeneity within old-growth stands promotes fungal diversity. The significant differences in root-associated fungal communities between the two pine species highlights that they are likely engaged in different bi-directional selection with fungal communities.

Shifts in root and soil chemistry drive the assembly of belowground fungal communities in tropical land-use systems

The conversion of highly diverse tropical lowland rainforests to monocultures of oil palm and rubber leads to drastic changes in fungal community structures. The magnitude of structuring effects, driven by changes in root or soil properties, on trophic groups with different ecological functions (mycorrhiza, saprotrophs, and pathogens) remains unknown. Here, we investigated shifts in the composition of different ecological groups of soil- and root-inhabiting fungi in response to changes in the soil and root chemistry of different land-use systems. We found an unexpectedly high turnover and low nestedness between local root and soil communities. In addition to soil pH, the root chemistry, especially root C/N, had strong bottom-up regulatory effects on the root-associated fungal assemblages, while root vitality had strong effects on the soil-residing fungi. Changes in root and soil chemistry drove divergent responses in different functional groups and had a stronger impact on fungal community structures than geographic distance. Our results suggest that changes in root chemistry promote the assemblage of specific root-associated fungal communities, largely independent of the surrounding soil community. Consequently, the recovery of root traits in intense land-use systems may stabilize the fungal communities against abiotic changes.

DNA-Metabarcoding of Belowground Fungal Communities in Bare-Root Forest Nurseries: Focus on Different Tree Species.

The production of tree seedlings in forest nurseries and their use in the replanting of clear-cut forest sites is a common practice in the temperate and boreal forests of Europe. Although conifers dominate on replanted sites, in recent years, deciduous tree species have received more attention due to their often-higher resilience to abiotic and biotic stress factors. The aim of the present study was to assess the belowground fungal communities of bare-root cultivated seedlings of Alnus glutinosa, Betula pendula, Pinus sylvestris, Picea abies and Quercus robur in order to gain a better understanding of the associated fungi and oomycetes, and their potential effects on the seedling performance in forest nurseries and after outplanting. The study sites were at the seven largest bare-root forest nurseries in Lithuania. The sampling included the roots and adjacent soil of 2–3 year old healthy-looking seedlings. Following the isolation of the DNA from the individual root and soil samples, these were amplified using ITS rRNA as a marker, and subjected to high-throughput PacBio sequencing. The results showed the presence of 161,302 high-quality sequences, representing 2003 fungal and oomycete taxa. The most common fungi were Malassezia restricta (6.7% of all of the high-quality sequences), Wilcoxina mikolae (5.0%), Pustularia sp. 3993_4 (4.6%), and Fusarium oxysporum (3.5%). The most common oomycetes were Pythium ultimum var. ultimum (0.6%), Pythium heterothallicum (0.3%), Pythium spiculum (0.3%), and Pythium sylvaticum (0.2%). The coniferous tree species (P. abies and P. sylvestris) generally showed a higher richness of fungal taxa and a rather distinct fungal community composition compared to the deciduous tree species (A. glutinosa, B. pendula, and Q. robur). The results demonstrated that the seedling roots and the rhizosphere soil in forest nurseries support a high richness of fungal taxa. The seedling roots were primarily inhabited by saprotrophic and mycorrhizal fungi, while fungal pathogens and oomycetes were less abundant, showing that the cultivation practices used in forest nurseries secured both the production of high-quality planting stock and disease control.

Belowground fungal community diversity, composition and ecological functionality associated with winter wheat in conventional and organic agricultural systems.

Understanding the impacts of agricultural practices on belowground fungal communities is crucial in order to preserve biological diversity in agricultural soils and enhance their role in agroecosystem functioning. Although fungal communities are widely distributed, relatively few studies have correlated agricultural production practices. We investigated the diversity, composition and ecological functionality of fungal communities in roots of winter wheat (Triticum aestivum) growing in conventional and organic farming systems. Direct and nested polymerase chain reaction (PCR) amplifications spanning the internal transcribed spacer (ITS) region of the rDNA from pooled fine root samples were performed with two different sets of fungal specific primers. Fungal identification was carried out through similarity searches against validated reference sequences (RefSeq). The R package ‘picante’ and FUNGuild were used to analyse fungal community composition and trophic mode, respectively. Either by direct or cloning sequencing, 130 complete ITS sequences were clustered into 39 operational taxonomic units (OTUs) (25 singletons), belonging to the Ascomycota (24), the Basidiomycota (14) and to the Glomeromycota (1). Fungal communities from conventional farming sites are phylogenetically more related than expected by chance. Constrained ordination analysis identified total N, total S and Pcal that had a significant effect on the OTU’s abundance and distribution, and a further correlation with the diversity of the co-occurring vegetation could be hypothesised. The functional predictions based on FUNGuild suggested that conventional farming increased the presence of plant pathogenic fungi compared with organic farming. Based on diversity, OTU distribution, nutrition mode and the significant phylogenetic clustering of fungal communities, this study shows that fungal communities differ across sampling sites, depending on agricultural practices. Although it is not fully clear which factors determine the fungal communities, our findings suggest that organic farming systems have a positive effect on fungal communities in winter wheat crops.

Scale-Dependent Influences of Distance and Vegetation on the Composition of Aboveground and Belowground Tropical Fungal Communities.

Fungi provide essential ecosystem services and engage in a variety of symbiotic relationships with trees. In this study, we investigate the spatial relationship of trees and fungi at a community level. We characterized the spatial dynamics for above- and belowground fungi using a series of forest monitoring plots, at nested spatial scales, located in the tropical South Pacific,in Vanuatu. Fungal communities from different habitats were sampled using metagenomic analysis of the nuclear ribosomal ITS1 region. Fungal communities exhibited strong distance-decay of similarity across our entire sampling range (3-110,000m) and also at small spatial scales (< 50m). Unexpectedly, this pattern was inverted at an intermediate scale (3.7-26km). At large scales (80-110km), belowground and aboveground fungal communities responded inversely to increasing geographic distance. Aboveground fungal community turnover (beta diversity) was best explained, at all scales, by geographic distance. In contrast, belowground fungal community turnover was best explained by geographic distance at small scales and tree community composition at large scales. Fungal communities from various habitats respond differently to the influences of habitat and geographic distance. At large geographic distances (80-110km), community turnover for aboveground fungi is better explained by spatial distance, whereas community turnover for belowground fungi is better explained by plant community turnover. Future syntheses of spatial dynamics among fungal communities must explicitly consider geographic scale to appropriately contextualize community turnover.

Phragmites australis Associates with Belowground Fungal Communities Characterized by High Diversity and Pathogen Abundance

Microbial symbionts are gaining attention as crucial drivers of invasive species spread and dominance. To date, much research has quantified the net effects of plant–microbe interactions on the relative success of native and invasive species. However, little is known about how the structure (composition and diversity) of microbial symbionts can differ among native and invasive species, or vary across the invasive landscape. Here, we explore the structure of endosphere and soil fungal communities associated with a monoculture-forming widespread invader, Phragmites australis, and co-occurring native species. Using field survey data from marshes in coastal Louisiana, we tested three hypotheses: (1) Phragmites australis root and soil fungal communities differ from that of co-occurring natives, (2) Phragmites australis monocultures harbor distinct fungal communities at the expanding edge compared to the monodominant center, and (3) proximity to the P. australis invading front alters native root endosphere and soil fungal community structure. We found that P. australis cultivates root and soil fungal communities with higher richness, diversity, and pathogen abundances compared to native species. While P. australis was found to have higher endosphere pathogen abundances at its expanding edge compared to the monodominant center, we found no evidence of compositional changes or pathogen spillover in native species in close proximity to the invasion front. This work suggests that field measurements of fungal endosphere communities in native and invasive plants are useful to help understand (or rule out) mechanisms of invasion.

Distinct fungal successional trajectories following wildfire between soil horizons in a cold-temperate forest.

Soil fungi represent a major component of below-ground biodiversity that determines the succession and recovery of forests after disturbance. However, their successional trajectories and driving mechanisms following wildfire remain unclear. We examined fungal biomass, richness, composition and enzymes across three soil horizons (Oe, A1 and A2) along a near-complete fire chronosequence (1, 2, 8, 14, 30, 49 andc.260yr) in cold-temperate forests of the Great Khingan Mountains, China. The importance of soil properties, spatial distance and tree composition were also tested. Ectomycorrhizal fungal richness and β-glucosidase activity were strongly reduced by burning and significantly increased with 'time since fire' in the Oe horizon but not in the mineral horizons. Time since fire and soil C:N ratio were the primary drivers of fungal composition in the Oe and A1/A2 horizons, respectively. Ectomycorrhizal fungal composition was remarkably sensitive to fire history in the Oe horizon, while saprotroph community was strongly affected by time since fire in the deeper soil horizon and this effect emerged 18 years after fire in the A2 horizon. Our study demonstrates pronounced horizon-dependent successional trajectories following wildfire and indicates interactive effects of time since fire, soil stoichiometry and spatial distance in the reassembly of below-ground fungal communities in a cold and fire-prone region.

Altitudinal upwards shifts in fungal fruiting in the Alps.

Many plant and animal species are changing their latitudinal and/or altitudinal distributions in response to climate change, but whether fungi show similar changes is largely unknown. Here, we use historical fungal fruit body records from the European Alps to assess altitudinal changes in fungal fruiting between 1960 and 2010. We observe that many fungal species are fruiting at significantly higher elevations in 2010 compared to 1960, and especially so among soil-dwelling fungi. Wood-decay fungi, being dependent on the presence of one or a few host trees, show a slower response. Species growing at higher elevations changed their altitudinal fruiting patterns significantly more than lowland species. Environmental changes in high altitudes may lead to proportionally stronger responses, since high-altitude species live closer to their physiological limit. These aboveground changes in fruiting patterns probably mirror corresponding shifts in belowground fungal communities, suggesting parallel shifts in important ecosystem functions.

Restoration of belowground fungal communities in reclaimed landscapes of the Canadian boreal forest

The trajectory of forests establishing on reclaimed oil sands mines in the Canadian boreal forest is uncertain. Soil microbes, namely mycorrhizal fungi, partly underlie successional trajectories of plant communities, yet their role in restoration is often overlooked. Here, we tested the relative importance of common management tools used in restoration—species planted and soil placement—on the recovery of ectomycorrhizal fungal communities over 4 years. Importantly, we further compared the community assembly of fungi on reclaimed landscapes to that in reference ecosystems disturbed to different degrees. This latter test addresses whether disturbance intensity is more important than common management interventions to restore fungal communities in these ecosystems. Three main findings emerged. (1) The effect of tree species planted and soil placement on ectomycorrhizal fungal communities establishing on reclaimed landscapes was dynamic through time. (2) Disturbances that remove or disrupt the organic layer of soils substantially affect the composition of ectomycorrhizal fungal communities. (3) Shifts in the community composition of ectomycorrhizal fungi were driven to a greater extent by disturbance severity than either tree species planted or soil placement.