Ectomycorrhizal Fungal Diversity Research Articles

Ectomycorrhizal communities associated with silver fir seedlings (Abies alba Mill.) differ largely in mature silver fir stands and in Scots pine forecrops

Abstract Context The requirement for rebuilding forecrop stands besides replacement of meadow vegetation with forest plants and formation of soil humus is the presence of a compatible ectomycorrhizal (ECM) fungal community. Aims This study aims to assess ectomycorrhizal fungi diversity associated with silver fir (Abies alba Mill.) seedlings regenerating in silver fir stands and Scots pine forecrops. Methods One-year-old seedlings were sampled in six study sites: three mature fir forests and three pine forests. ECM fungi were identified by polymerase chain reaction amplification and sequencing of the internal transcribed spacer of rDNA. Results The mean mycorrhizal colonization exceeded 90 %. Thirty-six ectomycorrhizal taxa were identified in fir stands and 23 in pine forecrops; ten out of these species were common to both stands. The fungal communities were different between study sites (R = 0.1721, p = 0.0001). Tomentella stuposa was the only species present at all sites. Conclusion Silver fir seedlings in Scots pine forecrops supported smaller ECM fungal communities than communities identified in mature silver fir stands. Nevertheless, fungal colonization of seedling roots was similar in both cases. This suggests that pine stands afforested on formerly arable land bear enough ECM species to allow survival and growth of silver fir seedlings.

Ectomycorrhizal fungal communities associated with Masson pine (Pinus massoniana) and white oak (Quercus fabri) in a manganese mining region in Hunan Province, China

Abstract The ecological responses of ectomycorrhizal fungi to heavy-metal contamination could affect the establishment and survival of trees under stress conditions due to industrial mining operations. In this study, we investigated species composition and diversity of ectomycorrhizal fungi associated with Masson pine ( Pinus massoniana ) and white oak ( Quercus fabri ) growing in Xiangtan manganese mining area in China. Canonical correspondence analysis revealed that soil Mn, Cu, Cd and several other soil cofactors related to manganese mining activities simultaneously structured the ectomycorrhizal community; in addition, a strong host effect was observed. The pine ectomycorrhizal community was dominated by four taxa (Atheliaceae, Thelephoraceae, Russulaceae, and Cenococcum ), while the oak community was dominated by Thelephoraceae and Cenococcum . The relative abundance of Atheliaceae was positively correlated with soil manganese concentrations while that of Russulaceae decreased with increasing soil manganese. These ecological responses of ectomycorrhizal fungi may reflect the different physiological sensitivity of ectomycorrhizal fungal species to manganese.

Host plant richness explains diversity of ectomycorrhizal fungi: Response to the comment of Tedersooet al. (2014)

Exploring the relationships between the biodiversity of groups of interacting organisms yields insight into ecosystem stability and function (Hooper etal. ; Wardle ). We demonstrated positive relationships between host plant richness and ectomycorrhizal (EM) fungal diversity both in a field study in subtropical China (Gutianshan) and in a meta-analysis of temperate and tropical studies (Gao etal. ). However, based on re-evaluation of our data sets, Tedersoo etal. () argue that the observed positive correlation between EM fungal richness and EM plant richness at Gutianshan and also in our metastudies was based mainly from (i) a sampling design with inconsistent species pool and (ii) poor data compilation for the meta-analysis. Accordingly, we checked our data sets and repeated the analysis performed by Tedersoo etal. (). In contrast to Tedersoo etal. (), our re-analysis still confirms a positive effect of plant richness on EM fungal diversity in Gutianshan, temperate and tropical ecosystems, respectively.

Does host plant richness explain diversity of ectomycorrhizal fungi? Re‐evaluation of Gao et al. (2013) data sets reveals sampling effects

The generally positive relationship between biodiversity of groups of directly or indirectly interacting organisms is one of the most important ecological concepts (Gaston, 2000 Nature, 405, 220-227; Scherber C, Eisenhauer N, Weisser WW et al., 2010 Nature, 468, 553-556). In a recent issue of Molecular Ecology, Gao C, Shi N-N, Liu Y-X et al. (2013: 22, 3403-3414) reported that the richness of plants and ectomycorrhizal fungi is positively correlated both at local and at global scales. Here, we challenge these findings by re-analysis of data and ascribe the reported results to sampling effect and poor data compilation.

Persistence and detection of black truffle ectomycorrhizas in plantations: comparison between two field detection methods

Owners of black truffle (Tuber melanosporum) plantations are concerned about the persistence of its mycorrhizas and mycelium in the soil, especially until the appearance of the "truffle burn" areas and the triggering of sporocarp production, at least 5-7 years after planting truffle-inoculated seedlings. During this period, the farmer does not know whether his management is promoting black truffle development. To study the presence and abundance of T. melanosporum ectomycorrhizas in plantations, two sampling methods, direct sampling of root tips and soil core collection, are compared by analyzing 48 evergreen oak trees (Quercus ilex) inoculated with truffle. Those trees are grouped by age (<6, 6-9, >9 years old) and presence or absence of truffle production. T. melanosporum was present in 46 out of the 48 studied trees, and its ectomycorrhizas appeared in 65% of the ectomycorrhizal tips. Its abundance is significantly higher with productive trees and young trees. Direct sampling of root tips and soil core collection were equally effective in detecting this species, although soil core collection proved a better method to also evaluate ectomycorrhizal fungal diversity. To detect the presence of T. melanosporum in a given plantation, three samples suffice, with a single sample per random tree. Although the presence of mycorrhizas is not a sure sign of the future success of a black truffle plantation, its absence influences managers as to whether to continue culturing truffles in a plantation.

Ectomycorrhizal fungus diversity and community structure with natural and cultivated truffle hosts: applying lessons learned to future truffle culture

Since the first truffle plantations were established in France, Italy and other parts in the world, many studies have been carried out to improve their productivity and sustainability. Success of plantations is clearly related to the mycorrhizal status of the host trees over the years, from inoculated seedlings to truffle-producing trees. The experience gained in monitoring the ectomycorrhizal fungus status in cultivated truffle grounds has allowed us to develop an extensive catalogue of the ectomycorrhizal fungi present in truffle plantations. Herein, we summarize fungal community data from 85 references that represent different truffle studies in natural habitats and plantations. Approximately 25% of the ectomycorrhizae reported in the 85 references are common to most of the studies. In general, more fungal species are detected in productive plantations than in the non-productive ones. Truffle plantations display a diverse ectomycorrhizal fungal community, in which species of the genus Tuber are well represented. Tuber rufum and some members of Boletales are typically restricted to productive truffle plots. On the other hand, Hebeloma, Laccaria and Russula species are mostly associated with unproductive plots. Ectomycorrhizae belonging to Thelephoraceae are frequently found in mature truffle orchards but do not seem to affect sporocarp production. Several biotic and abiotic factors affect the ectomycorrhizal fungus communities associated with truffle orchards. Among them are plantation age, host species and its growth, the surrounding environment (particularly the presence of other ectomycorrhizal hosts), and plantation management. Understanding the ectomycorrhizal fungal communities inhabiting different plantations may give us clues about the dynamics of the targeted truffles and the possibility of identifying mycorrhizal fungal species that are good indicators of successful truffle plantations.

Studies on ectomycorrhizal basidiomycete in pine forest on the Lithuania-Poland transboundary region

The diversity of ectomycorrhizal fungi and sporocarps abundance were investigated in 2003-2005 at nine permanent study plots in a 50-year-old pine forest. Diversity of ectomycorrhizal fungi consisted of 53 taxa and the majority of them belonged to the genera &lt;em&gt;Cortinarius, Russula, Amanita&lt;/em&gt; and &lt;em&gt;Tricholoma&lt;/em&gt;. The most frequent species, whose fruit bodies were found in each study plot, were &lt;em&gt;C. cibarius, L. necator L. rufus, P. involutus, R. aeruginea, T. saponaceum&lt;/em&gt; and the most abundant species which made the main part of total sporocarp yield were &lt;em&gt;C. cibarius&lt;/em&gt; and &lt;em&gt;P. involutus&lt;/em&gt;. The lowest species richness of ectomycorrhizal fungi was in study plots with the densest cover of grasses. Maximum of species over the fruiting period was characteristic for October and for September. It was noticed that some species virtually never occurred together at the same plot (eg. &lt;em&gt;C. cibarius&lt;/em&gt; and &lt;em&gt;H. aurantiaca&lt;/em&gt;), meanwhile others occurred together quite frequently (eg. &lt;em&gt;H.aurantiaca&lt;/em&gt; and &lt;em&gt;X. badius&lt;/em&gt;).

Profiling functions of ectomycorrhizal diversity and root structuring in seedlings of Norway spruce (Picea abies) with fast‐ and slow‐growing phenotypes

We studied the role of taxonomical and functional ectomycorrhizal (ECM) fungal diversity in root formation and nutrient uptake by Norway spruce (Picea abies) seedlings with fast- and slow-growing phenotypes. Seedlings were grown with an increasing ECM fungal diversity gradient from one to four species and sampled before aboveground growth differences between the two phenotypes were apparent. ECM fungal colonization patterns were determined and functional diversity was assayed via measurements of potential enzyme activities of eight exoenzymes probably involved in nutrient mobilization. Phenotypes did not vary in their receptiveness to different ECM fungal species. However, seedlings of slow-growing phenotypes had higher fine-root density and thus more condensed root systems than fast-growing seedlings, but the potential enzyme activities of ectomycorrhizas did not differ qualitatively or quantitatively. ECM species richness increased host nutrient acquisition potential by diversifying the exoenzyme palette. Needle nitrogen content correlated positively with high chitinase activity of ectomycorrhizas. Rather than fast- and slow-growing phenotypes exhibiting differing receptiveness to ECM fungi, our results suggest that distinctions in fine-root structuring and in the belowground growth strategy already apparent at early stages of seedling development may explain later growth differences between fast- and slow-growing families.

Attributing functions to ectomycorrhizal fungal identities in assemblages for nitrogen acquisition under stress.

Mycorrhizal fungi have a key role in nitrogen (N) cycling, particularly in boreal and temperate ecosystems. However, the significance of ectomycorrhizal fungal (EMF) diversity for this important ecosystem function is unknown. Here, EMF taxon-specific N uptake was analyzed via (15)N isotope enrichment in complex root-associated assemblages and non-mycorrhizal root tips in controlled experiments. Specific (15)N enrichment in ectomycorrhizas, which represents the N influx and export, as well as the exchange of (15)N with the N pool of the root tip, was dependent on the fungal identity. Light or water deprivation revealed interspecific response diversity for N uptake. Partial taxon-specific N fluxes for ectomycorrhizas were assessed, and the benefits of EMF assemblages for plant N nutrition were estimated. We demonstrated that ectomycorrhizal assemblages provide advantages for inorganic N uptake compared with non-mycorrhizal roots under environmental constraints but not for unstressed plants. These benefits were realized via stress activation of distinct EMF taxa, which suggests significant functional diversity within EMF assemblages. We developed and validated a model that predicts net N flux into the plant based on taxon-specific (15)N enrichment in ectomycorrhizal root tips. These results open a new avenue to characterize the functional traits of EMF taxa in complex communities.

Ectomycorrhizal fungal diversity in Quercus ilex Mediterranean woodlands: variation among sites and over soil depth profiles in hyphal exploration types, species richness and community composition

Understanding the factors underlying the distribution of biodiversity is a challenging issue in ecology. Here, we examined the distribution patterns of ectomycorrhizal fungal diversity across the soil profile in three Quercus ilex forests. Contact exploration type strongly dominated at all sites, but was most prevalent in the upper, organic-rich soil layers. At each site, three quarters of the ectomycorrhizal tips and 59 % of taxa were restricted to the ten first centimeters of the soil profile. The relative abundance of the dominant family Russulaceae increased with increasing soil depth. Species composition varied significantly among sites, with most species being rare. Species that occurred in only one of the three sites accounted for 78.9 % of all species, and 57.3 % of species were represented by a single ECM root tip. Our results suggest that (i) rare species at both local and regional scales contribute to the highly diverse fungal assemblages in Mediterranean forests and (ii) multi-sites studies including the whole soil profile are needed to provide comprehensive overviews of the taxonomic and functional diversities of ectomycorrhizal communities.

The Major Factors Affecting Ectomycorrhizal Fungi Diversity in the Forest Ecosystem

Ectomycorrhizal fungi are important for plants growth which can enhance their resistance to drought, diseases, infertility and so on in the forest ecosystem, so researches on Ectomycorrhizal fungi are of necessity and great significance. As the basis for Ectomycorrhizal fungi research, the Ectomycorrhizal fungi diversity is attributed to many factors which can be divided to two parts in this review: biotic factors and abiotic factors. Biotic factors include chronosequences, bacteria living with ECM, habitat area, host genotype and abiotic factors include forest fire, toxic metal contamination, nitrogen content, survey method and microenvironment. The effects by these factors are deeply analyzed and discussed based on the plenty of literatures, our previous work and current research. The review not only introduces the current research result, but also arouses new ideas on Ectomycorrhizal fungi diversity research.

Tree species effects on nutrient cycling and soil biota: A feedback mechanism favouring species coexistence

We synthesise a series of independent but integrated studies on the functioning of a mixed Mediterranean oak forest to demonstrate the tree–soil interactions underpinning a positive feedback process that sustains the coexistence of two oak species. The studies focused on the foliar functional traits, plant regeneration patterns, biogeochemical cycles, soil microbial biomass and ectomycorrhizal (ECM) fungal diversity associated with the co-dominant evergreen Quercus suber and deciduous Quercus canariensis in a Mediterranean forest in southern Spain.Foliar attributes differed between oak species, with Q. canariensis having higher nutrient content and lower carbon to nutrient ratios and leaf mass per area than Q. suber. These attributes reflected their distinct resource use strategies and adaptation to high and low resource-availability environments, respectively. Leaf-fall nutrient concentrations were higher in Q. canariensis than in Q. suber and were correlated with concentrations in the fresh leaves. Leaf-fall nutrient concentrations influenced nutrient return, leaf-fall decay rate and the proportion of nutrients released from decomposing leaf-fall, all of which were higher for Q. canariensis than for Q. suber. This generated a differential net nutrient input into the soil that led to increased soil nutrient concentrations under the canopy of Q. canariensis as compared to Q. suber. The fraction of slowly decomposing leaf-fall that builds up soil organic matter was higher for Q. canariensis, further raising the nutrient and moisture retention of its soils. Differences between species in soil properties disappeared with increasing soil depth, which was consistent with the hypothesised leaf-fall-mediated effect. Tree-species-generated changes in soil properties had further impacts on soil organisms. Soil microbial biomass (Cmic) and nutrients (Nmic, Pmic) were higher under Q. canariensis than under Q. suber and were positively related to soil moisture content and substrate availability (particularly soil N). The composition of the ECM fungal community shifted between the two oaks in response to changes in the soil properties, particularly soil Ca and pH. Lower ECM phylogenetic diversity and higher abundance of mycorrhizal species with saprophytic abilities were related to the greater soil fertility under Q. canariensis. Overall, the two oak species generated soil conditions that aligned with their resource-use strategies and would enhance their own competitive capabilities, potentially creating a positive feedback. The two Quercus created soil spatial heterogeneity that could enable their coexistence through spatial niche partitioning. This study demonstrates the critical role of aboveground-belowground interactions underpinning forest community composition.

Host plant genus‐level diversity is the best predictor of ectomycorrhizal fungal diversity in a Chinese subtropical forest

Microbial diversity is generally far higher than plant diversity, but the relationship between microbial diversity and plant diversity remains enigmatic. To shed light on this problem, we examined the diversity of a key guild of root-associated microbes,that is, ectomycorrhizal (EM) fungi along a plant diversity gradient in a Chinese subtropical forest. The results indicated that EM fungal diversity was positively correlated with host plant diversity. Furthermore, this relationship was best predicted by host genus-level diversity, rather than species-level diversity or family-level diversity. The generality of this finding was extended beyond our study system through the analyses of 100 additional studies of EM fungal communities from tropical and temperate forests.Here as well, EM fungal lineage composition was significantly affected by EM plant diversity levels, and some EM fungal lineages were co-associated with some host plant genera. These results suggest a general diversity maintenance mechanism for host-specific microbes based on higher order host plant phylogenetic diversity.

Uncommon ectomycorrhizal networks: richness and distribution of Alnus‐associating ectomycorrhizal fungal communities

Uncommon ectomycorrhizal networks: richness and distribution of <i>Alnus</i>‐associating ectomycorrhizal fungal communities

Distribution of ectomycorrhizal fungi in a Chamaecyparis obtusa stand at different distances from a mature Quercus serrata tree

Ectomycorrhizal fungal distributions at different distances from one mature Quercus serrata tree were demonstrated in a Japanese cypress stand. After 4 months for field-planted and 3 months for laboratory-incubated Q. serrata seedlings, they were evaluated ectomycorrhiza formations. For the field-planted seedlings, molecular discrimination was conducted to clarify the species diversity of ectomycorrhizal fungi. Ectomycorrhiza formation was confirmed at all distances in both methods. However, the formation and associating fungal species were decreased with increasing distance. These results indicate that the density and diversity of ectomycorrhizal fungi decrease rapidly within several tens of meters from arbuscular mycorrhizal forest edges.

Environmental barcoding of the ectomycorrhizal fungal genus Cortinarius

Understanding the role of ectomycorrhizal fungi in plant communities is hampered by a lack of knowledge about fungal diversity. DNA barcoding of the ectomycorrhizal fungal genus Cortinarius was used to compare fungal diversity in soil from four plant communities: (i) Nothofagus forest (where Cortinarius is common and diverse), (ii) Kunzea forest (where Cortinarius is present but with low diversity), (iii) a Pinus radiata plantation (Cortinarius is not thought to be present) and (iv) a sub-Antarctic island (where known ectomycorrhizal hosts are absent). PCR primers specific for the ITS region of Cortinarius species were developed. Specificity was tested in vitro and in silico against DNA from basidiocarps of Cortinarius and non-Cortinarius species. The primers were tested for their ability to amplify Cortinarius DNA in soil from forests of the three ectomycorrhizal forest communities and a range of soils from the ectomycorrhiza-free subantarctic Campbell Island. High diversity of Cortinarius was associated with soil of all three ectomycorrhizal communities, despite Cortinarius being previously unrecorded from Pinus. Soil from all three communities share some ectomycorrhizal fungi (including fungi shared between native and exotic hosts), having implications for community succession, introduction of exotic fungi and biodiversity assessment. No Cortinarius was detected from Campbell Island samples. The validated molecular protocol assessed species diversity in a rapid and cost effective way. Baseline biodiversity assessment based on DNA barcoding is more effective at detecting diversity than traditional methods, but requires careful consideration of the difference between ectomycorrhizal fungal diversity in soil versus root-tips.

Ectomycorrhizal diversity enhances growth and nitrogen fixation of Acacia mangium seedlings

Increasing interest has been given so far to the role of mycorrhizal symbiosis on plant diversity and ecosystem productivity. However much remains unknown about the effect of ectomycorrhizal fungal diversity on plant growth and rhizobial symbiosis. The purpose of this study is to investigate the influence of ectomycorrhizal diversity on root nodulation and plant nutrient uptake during plant growth. A gradient of ectomycorrhizal diversity was created (ranged from one to six fungal isolates) on Australian Acacia (Acacia mangium) seedlings grown on a phosphate-deficient soil in controlled conditions. The results clearly show (i) an enhancement of A. mangium growth due to ectomycorrhizal fungal inoculation, (ii) as well as significant effects of increasing ectomycorhizal diversity and soil ectomycorrhizal mycelium density on whole plant biomass and plant nutrient uptake. They also reveal an effect of ectomycorrhizal diversity effect on the functioning of the nitrogen-fixing symbiosis. These results emphasize the need to manage soil ectomycorrhizal potential (abundance and diversity of ectomycorrhizal mycelium) in forest management practices in order to optimize N2 fixation and seedling growth, leading thus to dramatic improvements in outplanting performances with fast-growing tree legumes on various reafforestation sites, more particularly in tropical and Mediterranean areas.

Diversity of ectomycorrhizal fungus assemblages on nursery grown European beech seedlings

Abstract• ContextAn important feature of forest nursery management is the production of first-rate planting stock, which is closely connected with an adequate development of ectomycorrhizas on seedling roots.• AimsThe aim of this study was to provide a detailed assessment of the ectomycorrhizal (ECM) fungal diversity of European beech grown in bare-root forest nursery conditions.• MethodsMorphological and molecular analyzes were used to identify ECM fungi, quantify fungal richness, and record differences in the relative abundance of individual taxa.• ResultsTwenty-seven different mycorrhizal fungal taxa were found in four tested nurseries. Of these 27, only 6 were present in more than one nursery. Taxa richness in individual nurseries ranged from 6 to 13, indicating that ECM colonization potential is nursery-dependent. The most frequent taxa were:Tubersp. 1,Cadophorasp.,Cenococcum geophilumagg.,Hebeloma sacchariolens, andLaccaria tortilis.According to the analysis of similarity, ECM fungal communities were significantly different between nurseries (R = 0.7741;p &lt; 0.0001).• ConclusionBeech seedlings grown in bare-root nurseries are colonized by a highly diverse suite of ECM fungi; thus, artificial inoculation of seedlings is generally not necessary in nursery practice.

Ectomycorrhizal community structure in chronosequences of Pinus densiflora in eastern China

Ectomycorrhizal (ECM) fungal communities of Pinus densiflora were studied along a chronosequence. Four age classes were sampled: 5, 30, 55 and 80 year-old. Morphotyping (anatomical and morphological identification) and molecular analysis (internal transcribed spacer region amplification and sequencing) were used to identify ECM root tips. A total of 43 ECM morphotypes were distinguished, 38 of which were successfully sequenced. Cenococcum geophilum, Cortinarius sp.1, Rhizopogon sp.1, and Russula densifolia dominated the ectomycorrhiza community of P. densiflora. C. geophilum had its peak of abundance in the 5-year-old stand, R. densifolia in the 30 year-old stand and Cortinarius sp.1 in the 80 year-old stand. However abundance ofRhizopogon sp.1 differed little with stand age. ECM fungus species diversity indices increased with stand age along the chronosequence. ECM fungal species diversity was significantly higher in the 5 year-old than in the 30 year-old stand and 55 and 80 year-old stands had similar diversities. Key words: Diversity, ectomycorrhizal, ITS, Pinus densiflora.

Habitat and diversity of ectomycorrhizal fungi in forests of South Cameroon

Information is lacking on habitat and diversity of ectomycorrhizal (ECM) fungi of African humid forests. For three years, mushroom excursions were carried out in four sites with contrasted soil and altitude characteristics of South Cameroon, during wet seasons. Collected fungi were described in fresh state and dried exsiccates examined for microscopic description before morpho-anatomical identification. ECM fungi abundantly fruited exclusively in mixed caesalp, monodominant Gilbertiodendron and Uapaca forest clumps, independently of elevation, rainfall, topography and soil texture. 21 ECM tree species in 11 genera belonging to two families, Ceasalpiniaceae and Phyllanthaceae, dominated ECM forest clumps. More than 100 putative ECM fungal species in 27 genera were identified and assigned to seven families and one super family group. Members of Russulaceae and Amanitaceae recruited the highest number of ECM taxa, followed by species of Boletoids and Cantharellaceae. Paxillus, Clavulina, Coltricia, Scleroderma, Cortinarius and Inocybe genera contained limited species. 12 ECM fungal species were locally edible, including Lactarius gymnocarpus and all chanterelles. Though, species richness was very large in a mountainous area, all four sites shared a substantial large number of ECM mushroom species. Low plant diversity but high fungal richness recommends ECM forest clumps for biodiversity sanctuaries.