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Ectomycorrhizal fungi have huge potential value, both nutritionally and economically, but most of them cannot be cultivated artificially. To better understand the influence of abiotic and biotic factors upon the growth of ectomycorrhizal fungi, mycosphere soil and bulk soil of five ectomycorrhizal fungi (Calvatia candida, Russula brevipes, Leucopaxillus laterarius, Leucopaxillus giganteus, and Lepista panaeola) were used as research objects for this study. Illumina MiSeq sequencing technology was used to analyze the community structure of the mycosphere and bulk soil bacteria of the five ectomycorrhizal fungi, and a comprehensive analysis was conducted based on soil physicochemical properties. Our results show that the mycosphere soil bacteria of the five ectomycorrhizal fungi are slightly different. Escherichia, Usitatibacter, and Bradyrhizobium are potential mycorrhizal-helper bacteria of distinct ectomycorrhizal fungi. Soil water content, soil pH, and available potassium are the main factors shaping the soil bacterial community of the studied ectomycorrhizal fungi. Moreover, from the KEGG functional prediction and LEfSe analysis, there are significant functional differences not only between the mycosphere soil and bulk soil. ‘Biosynthesis of terpenoidsand steroids’, ‘alpha-Linolenic acid metabolism’, ‘Longevity regulating pathway-multiple species’, ‘D-Arginine and D-ornithine metabolism’, ‘Nitrotoluene degradation’ and other functions were significantly different in mycosphere soil. These findings have pivotal implications for the sustainable utilization of ectomycorrhizal fungi, the expansion of edible fungus cultivation in forest environments, and the enhancement of derived economic benefits.

Species of the basidiomycetous genus Tomentella are widely distributed throughout temperate forests. Numerous studies on the taxonomy and phylogeny of Tomentella have been conducted from the temperate zone in the Northern hemisphere, but few have been from subtropical forests. In this study, four new species, T. casiae, T. guiyangensis, T. olivaceomarginata and T. rotundata from the subtropical mixed forests of Southwestern China, are described and illustrated based on morphological characteristics and phylogenetic analyses of the internal transcribed spacer regions (ITS) and the large subunit of the nuclear ribosomal RNA gene (LSU). Molecular analyses using Maximum Likelihood and Bayesian analysis confirmed the phylogenetic positions of these four new species. Anatomical comparisons among the closely related species in phylogenetic and morphological features are discussed. Four new species could be distinguished by the characteristics of basidiocarps, the color of the hymenophoral surface, the size of the basidia, the shape of the basidiospores and some other features.

The genus Tarzetta is distributed mainly in temperate forests and establishes ectomycorrhizal associations with angiosperms and gymnosperms. Studies on this genus are scarce in México. A visual, morphological, and molecular (ITS-LSU) description of T. americupularis, T. cupressicola, T. davidii, T. durangensis, T. mesophila, T. mexicana, T. miquihuanensis, T. poblana, T. pseudobronca, T. texcocana, and T. victoriana was carried out in this work, associated with Abies, Quercus, and Pinus. The results of SEM showed an ornamented ascospores formation by Mexican Taxa; furthermore, the results showed that T. catinus and T. cupularis are only distributed in Europe and are not associated with any American host.

Pisolithus albus ( Basidiomycota , Sclerodermataceae ) is reported here for the first time from Egypt where it was found on the Karaman Island in Sohag Governorate. It was found forming an ectomycorrhizal association with Eucalyptus occidentalis and Vachellia nilotica . The fungus was also reported near two potentially new hosts: Paspalum distichum and Dodonaea viscosa ; however, the mycorrhizal connections with these two hosts is not proven. Phylogenetic analyses for the combined ITS and LSU rDNA sequences dataset placed the Egyptian specimen within the Pisolithus albus complex clade. It is described, illustrated, and phylogenetically analyzed in this article. Various hosts and locations of the taxon are reviewed.

Invasive plant pathogenic fungi have a global impact, with devastating economic and environmental effects on crops and forests. Biosurveillance, a critical component of threat mitigation, requires risk prediction based on fungal lifestyles and traits. Recent studies have revealed distinct genomic patterns associated with specific groups of plant pathogenic fungi. We sought to establish whether these phytopathogenic genomic patterns hold across diverse taxonomic and ecological groups from the Ascomycota and Basidiomycota, and furthermore, if those patterns can be used in a predictive capacity for biosurveillance. Using a supervised machine learning approach that integrates phylogenetic and genomic data, we analyzed 387 fungal genomes to test a proof-of-concept for the use of genomic signatures in predicting fungal phytopathogenic lifestyles and traits during biosurveillance activities. Our machine learning feature sets were derived from genome annotation data of carbohydrate-active enzymes (CAZymes), peptidases, secondary metabolite clusters (SMCs), transporters, and transcription factors. We found that machine learning could successfully predict fungal lifestyles and traits across taxonomic groups, with the best predictive performance coming from feature sets comprising CAZyme, peptidase, and SMC data. While phylogeny was an important component in most predictions, the inclusion of genomic data improved prediction performance for every lifestyle and trait tested. Plant pathogenicity was one of the best-predicted traits, showing the promise of predictive genomics for biosurveillance applications. Furthermore, our machine learning approach revealed expansions in the number of genes from specific CAZyme and peptidase families in the genomes of plant pathogens compared to non-phytopathogenic genomes (saprotrophs, endo- and ectomycorrhizal fungi). Such genomic feature profiles give insight into the evolution of fungal phytopathogenicity and could be useful to predict the risks of unknown fungi in future biosurveillance activities. [ABSTRACT FROM AUTHOR]

To explore the contribution of microorganisms to forest ecosystem function, we studied the ectomycorrhizal (ECM) fungal and soil bacterial community of the five typical tree species (Pinus massoniana, PM; Castanopsis carlesii, CC; Castanopsis eyrei, CE; Castanopsis fargesii, CF; and Keteleeria cyclolepis, KC) at the Junzifeng National Nature Reserve. The results indicated that the ECM fungal and soil bacterial diversity of CC and CF was similar, and the diversity rates of CC and CF were higher than those of PM, CE, and KC. Cenococcum geophilum and unclassified_Cortinariaceae II were the most prevalent occurring ECM fungi species in the five typical tree species, followed by unclassified_Cortinariaceae I and Lactarius atrofuscus. In bacteria, the dominant bacterial genera were Acidothermus, Bradyrhizobium, Acidibacter, Candidatus_Solibacter, Candidatus_Koribacter, Roseiarcus, and Bryobacter. EMF fungi and soil bacteria were correlated with edaphic factors, especially the soil pH, TP, and TK, caused by stand development. The results show that the community characteristics of ECM fungi and bacteria in the typical tree species of the Junzifeng National Nature Reserve reflect the critical role of soil microorganisms in stabilizing forest ecosystems. [ABSTRACT FROM AUTHOR]

Species interactions exhibit varying degrees of specialization, ranging from generalist to specialist interactions. For many interactions (e.g., plantmicrobiome) we lack standardized metrics of specialization, hindering our ability to apply comparative frameworks of specificity across niche axes and organismal groups. Here, we discuss the concept of plant host specificity of arbuscular mycorrhizal (AM) fungi and ectomycorrhizal (EM) fungi, including the predominant theories for their interactions: Passenger, Driver, and Habitat Hypotheses. We focus on five major areas of interest in advancing the field of plant-mycorrhizal fungal host specificity: phylogenetic specificity, host physiology specificity, functional specificity, habitat specificity, and mycorrhizal fungal-mediated plant rarity. Considering the need to elucidate foundational concepts of specificity in this globally important symbiosis, we propose standardized metrics and comparative studies to enhance our understanding. We also emphasize the importance of analyzing global mycorrhizal data holistically to draw meaningful conclusions and suggest a shift toward singlespecies analyses to unravel the complexities underlying these associations. [ABSTRACT FROM AUTHOR]

Increasing terrestrial ecosystem carbon sink is an effective way to mitigate the rise of atmospheric carbon dioxide (CO2) concentration and achieve the goal of "carbon neutrality". Mycorrhizal fungi are beneficial microorganisms that can form symbiotic relationships with 90% of plants in terrestrial ecosystems, and the symbiont contributes significantly to soil and plant carbon sink. In the review, we take arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF), which are the most extensively studied currently, as the narrative objects, and discuss the carbon sink enhancement potential of mycorrhizal fungi from the following four aspects. The first, mycorrhizal fungi indirectly increase the plant carbon sink by promoting photosynthesis and increasing biomass in the host plant, and this advantage can be maintained even under stressful conditions. The second, the process of carbon source transportation between AMF-plant symbionts and EMF-plant symbionts is described in this paper. The third, review describes that mycorrhizal fungi contribute to soil carbon sink by increasing carbon input as well as decreasing carbon output. The fourth, we point out the shortcomings of the current study and provide a prospect for future research, with the aim to provide theoretical support for increasing terrestrial carbon sink. [ABSTRACT FROM AUTHOR]

During the 1970s and 1980s, L. R. Hesler and A. H. Smith, alone, together, or Smith with other authors such as V. S. Evenson and D. H. Mitchel, described numerous North American taxa in Hebeloma. With the inclusion of an early work by Smith and a later work by E. Grilli, who described a species based on material from Smith, 130 taxa were described and form the subject of this paper. Apart from two taxa that were (deliberately) invalidly published and two that were illegitimately published, all others are valid and legitimate names. After study of morphology, habitat, and location of collection (based on available material and information) as well as molecular analysis (insofar as this was successful), of these 128 validly published taxa we regard 14 as being current names; the remaining 114 are synonymized with other current names. These 14 species are Hebeloma albomarginatum, H. alpinicola, H. angelesiense, H. caulocystidiosum, H. immutabile, H. incarnatulum, H. kelloggense, H. mackinawense, H. nitidum, H. olympianum, H. parcivelum, H. praeolidum, H. pungens, and H. sporadicum. This brings up the number of currently recognized, validly published, Hebeloma species in America to 72. [ABSTRACT FROM AUTHOR]

Tricholoma bakamatsutake, which is an edible ectomycorrhizal fungus associated with Fagaceae trees, may have diverged before the other species in Tricholoma section Caligata. We generated a highly contiguous whole-genome sequence for T. bakamatsutake SF-Tf05 isolated in an Oak (Quercus salicina) forest in Japan. The assembly of high-fidelity long reads, with a median read length of 12.3 kb, resulted in 13 chromosome-sized contigs comprising 142,068,211 bases with an average guanine and cytosine (GC) content of 43.94%. The 13 chromosomes were predicted to encode 11,060 genes. A contig (122,566 bases) presumably containing the whole circular mitochondrial genome was also recovered. The chromosome-wide comparison of T. bakamatsutake and Tricholoma matsutake (TMA_r1.0) indicated that the basic number of chromosomes (13) was conserved, but the structures of the corresponding chromosomes diverged, with multiple inversions and translocations. Gene conservation and cluster analyses revealed at least 3 phylogenetic clades in Tricholoma section Caligata. Specifically, all T. bakamatsutake strains belonged to the "bakamatsutake" clade, which is most proximal to the "caligatum" clade consisting of Tricholoma caligatum and Tricholoma fulvocastaneum. The constructed highly contiguous nearly telomere-to-telomere genome sequence of a T. bakamatsutake isolate will serve as a fundamental resource for future research on the evolution and differentiation of Tricholoma species. [ABSTRACT FROM AUTHOR]

Ectomycorrhizal fungi can absorb heavy metals and allow host plants to develop resistance to heavy metal stress, but their heavy metal tolerance is not fully understood. In this study, the ability of Suillus bovinus (Sb) and Suillus placidus (Sp) to tolerate cadmium (Cd) was evaluated. Sb and Sp were treated with different Cd concentrations (0 (control), 0.2, 0.4 and 0.8 mg/L) under pure culture conditions, and the biomass, osmotic adjustment substance contents (soluble sugar and soluble protein), antioxidant enzyme activities (superoxide dismutase (SOD) and catalase (CAT)), pH and conductivity were examined. Sb biomass, soluble protein content and SOD activity first increased (0.2 mg/L and 0.4 mg/L Cd) and then decreased (0.8 mg/L Cd). Sp showed a similar change rule but a smaller range. Cd treatment increased the CAT activity of Sb and Sp but significantly reduced soluble sugars in Sb mycelium, whereas 0.2 mg/L Cd significantly increased soluble sugars in Sp mycelium. The pH and conductivity in the medium of Sb treated with different Cd concentrations showed more significant changes than those of Sp. The pH of Sp at 0 mg/L Cd and conductivity at 0.8 mg/L Cd were significantly lower than those of Sb. Correlation analysis suggested that Cd affected Sb more than Sp. In general, Cd treatment had less effect on the indexes of Sp, and Sp tolerated Cd better than Sb. [ABSTRACT FROM AUTHOR]

Enhanced nitrogen (N) availability in temperate forests has altered ecosystem carbon (C) and N cycling. Recent research has shown that these alterations lead to reductions in belowground C allocation by trees and that the consequences of these reductions on soil C and nutrient cycling may vary by mycorrhizal type. We hypothesized that trees that associate with ectomycorrhizal fungi (ECM) would reduce C allocation towards roots and mycorrhizal fungi to a greater extent than trees that associate with arbuscular mycorrhizal fungi (AM) in response to > 25 years of N fertilization. We further hypothesized that N induced decoupling of roots and microbes in ECM trees would be evidenced by greater declines in extracellular enzyme activities. We measured belowground C allocation to fine root biomass and mycorrhizal colonization in 6 AM and 6 ECM dominated plots in the N fertilized and reference watersheds at the Fernow Experimental Forest in West Virginia, USA. We compared these to measurements of simple-C, complex-C, nitrogen, and phosphorus acquiring enzyme activities in organic horizon, bulk mineral, and rhizosphere soil fractions. N fertilization reduced fine root biomass and mycorrhizal colonization in both AM and ECM stands. We found more consistent reductions in enzyme activities in ECM soils than AM soils under N fertilization which may have been driven by greater declines in root-C transfer to soil microbes. This mechanism helps to explain variability in soil C cycling responses across N gradient and fertilization experiments and may prove useful in predicting the fate of soil C stocks in response to N deposition. [ABSTRACT FROM AUTHOR]

Poplar is a short‐rotation woody crop frequently studied for its significance as a sustainable bioenergy source. The successful establishment of a poplar plantation partially depends on its rhizosphere—a dynamic zone governed by complex interactions between plant roots and a plethora of commensal, mutualistic, symbiotic, or pathogenic microbes that shape plant fitness. In an exploratory endeavor, we investigated the effects of a consortium consisting of ectomycorrhizal fungi and a beneficial Pseudomonas sp. strain GM41 on plant growth (including height, stem girth, leaf, and root growth) and as well as growth rate over time, across four Populus trichocarpa genotypes. Additionally, we compared the level of total organic carbon and plant exometabolite profiles across different poplar genotypes in the presence of the microbial consortium. These data revealed no significant difference in plant growth parameters between the treatments and the control across four different poplar genotypes at 7 weeks post‐inoculation. However, total organic carbon and exometabolite profiles were significantly different between the genotypes and the treatments. These findings suggest that this microbial consortium has the potential to trigger early signaling responses in poplar, influencing its metabolism in ways crucial for later developmental processes and stress tolerance. [ABSTRACT FROM AUTHOR]

Plant mycorrhizal associations influence the accumulation and persistence of soil organic matter and could therefore shape ecosystem biogeochemical responses to global changes that are altering forest composition. For instance, arbuscular mycorrhizal (AM) tree dominance is increasing in temperate forests, and ericoid mycorrhizal (ErM) shrubs can respond positively to canopy disturbances. Yet how shifts in the co‐occurrence of trees and shrubs with different mycorrhizal associations will affect soil organic matter pools remains largely unknown. We examine the effects of ErM shrubs on soil carbon and nitrogen stocks and indicators of microbial activity at different depths across gradients of AM versus ectomycorrhizal (EcM) tree dominance in three temperate forest sites. We find that ErM shrubs strongly modulate tree mycorrhizal dominance effects. In surface soils, ErM shrubs increase particulate organic matter accumulation and weaken the positive relationship between soil organic matter stocks and indicators of microbial activity. These effects are strongest under AM trees that lack fungal symbionts that can degrade organic matter. In subsurface soil organic matter pools, by contrast, tree mycorrhizal dominance effects are stronger than those of ErM shrubs. Ectomycorrhizal tree dominance has a negative influence on particulate and mineral‐associated soil organic matter pools, and these effects are stronger for nitrogen than for carbon stocks. Our findings suggest that increasing co‐occurrence of ErM shrubs and AM trees will enhance particulate organic matter accumulation in surface soils by suppressing microbial activity while having little influence on mineral‐associated organic matter in subsurface soils. Our study highlights the importance of considering interactions between co‐occurring plant mycorrhizal types, as well as their depth‐dependent effects, for projecting changes in soil carbon and nitrogen stocks in response to compositional shifts in temperate forests driven by disturbances and global change. [ABSTRACT FROM AUTHOR]

Hydnum is a genus of ectomycorrhizal fungi belonging to the Hydnaceae family. It is widely distributed across different regions of the world, including North America, Europe, and Asia; however, some of them showed disjunct distributions. In recent years, with the integration of molecular techniques, the taxonomy and classification of Hydnum have undergone several revisions and advancements. However, these changes have not yet been applied in the Republic of Korea. In this study, we conducted an integrated analysis combining the morphological and molecular analyses of 30 specimens collected over a period of approximately 10 years in the Republic of Korea. For molecular analysis, the sequence data of the internal transcribed spacer (ITS) region, the large subunit of nuclear ribosomal RNA gene (nrLSU), and a portion of translation elongation factor 1-α (TEF1) were employed as molecular markers. Through this study, we identified eight species that had previously not been reported to occur in the Republic of Korea, including one new species, Hydnum paucispinum. A taxonomic key and detailed descriptions of the eight Hydnum species are provided in this study. [ABSTRACT FROM AUTHOR]

Tricholoma matsutake has been the most valuable ectomycorrhizal fungi in Asia because of its unique flavor and taste. However, due to the difficulty of artificial cultivation, the cultivation of T. matsutake has relied on natural growth in forests. To cultivate the T. matsutake artificially, microorganisms in fairy rings were introduced. In this study, we isolated 30 fungal species of microfungi from the soil of fairy rings. Among them, one single fungal strain showed a promoting effect on the growth of T. matsutake. The growth effect was confirmed by measuring the growth area of T. matsutake and enzyme activities including a-amylase, cellulase, and b-glucosidase. In comparison with control, microfungal metabolite increased the growth area of T. matsutake by 213% and the enzyme activity of T. matsutake by 110-200%. The isolated fungal strain was identified as Penicillium citreonigrum by BLAST on the NCBI database. The Discovery of this microfungal strain is expected to contribute to artificial cultivation of T. matsutake. [ABSTRACT FROM AUTHOR]

Summary: Drainage‐induced encroachment by trees may have major effects on the carbon balance of northern peatlands, and responses of microbial communities are likely to play a central mechanistic role.We profiled the soil fungal community and estimated its genetic potential for the decay of lignin and phenolics (class II peroxidase potential) along peatland drainage gradients stretching from interior locations (undrained, open) to ditched locations (drained, forested).Mycorrhizal fungi dominated the community across the gradients. When moving towards ditches, the dominant type of mycorrhizal association abruptly shifted from ericoid mycorrhiza to ectomycorrhiza at c. 120 m from the ditches. This distance corresponded with increased peat loss, from which more than half may be attributed to oxidation. The ectomycorrhizal genus Cortinarius dominated at the drained end of the gradients and its relatively higher genetic potential to produce class II peroxidases (together with Mycena) was positively associated with peat humification and negatively with carbon‐to‐nitrogen ratio.Our study is consistent with a plant–soil feedback mechanism, driven by a shift in the mycorrhizal type of vegetation, that potentially mediates changes in aerobic decomposition during postdrainage succession. Such feedback may have long‐term legacy effects upon postdrainage restoration efforts and implication for tree encroachment onto carbon‐rich soils globally. See also the Commentary on this article by Parker and Clemmensen, 240: 10–12. [ABSTRACT FROM AUTHOR]

Garry oak (Quercus garryana Douglas ex Hook.) is the only oak native to British Columbia (BC), where it occupies the northernmost extent of its range. The ecosystem it occupies in BC has been greatly reduced in size and fragmented by European settlement. Garry oak forms ectomycorrhizas that are essential to its existence and will likely play an important role in the response of this tree to climate change. Yet, relatively little is known about the ectomycorrhizal fungi associated with Garry oak in BC. In this study, we have documented the occurrence of fungi forming ectomycorrhizas with Garry oak at six locations on Vancouver Island by sequencing the internal transcribed spacer region of ectomycorrhizal root tips collected from Garry oak stands. Of the 47 species we detected, only about 20% can be confidently assigned to known species because not all species have been sequenced and many sequences in public databases are incorrectly or incompletely identified, but the majority of them belong to a community of fungi associated primarily with oaks or other members of Fagaceae. The uniqueness of this community of ectomycorrhizal fungi indicates that the possible expansion of the range of Garry oak in BC in response to climate change may be limited by the co-migration of its ectomycorrhizal fungi. [ABSTRACT FROM AUTHOR]

Aims: Encroachment of woody species into grasslands is a global phenomenon that affects ecosystem services, including soil organic carbon (SOC) storage and microbial community structure. We determined stocks of SOC and soil microbial biomass as affected by conversion of grasslands to coniferous forests. Methods: We examined SOC and soil δ13C signatures under three vegetation covers: native grasslands, eastern redcedar (Juniperus virginiana), and ponderosa pine (Pinus ponderosa), at six soil depths (0 − 10, 10 − 30, 30 − 100, 100 − 170, 170 − 240, 240 − 300 cm). Fatty acid methyl esters (FAMEs) were used to quantify soil microbial biomass (MB) and as biomarkers for bacteria, arbuscular mycorrhizal fungi (AMF), and saprophytic fungi (SF) which includes ectomycorrhizal fungi (ECM). Results: Native grasslands had higher overall SOC and MB stocks in the top 300 cm soil depth (7.39 kg SOC m− 2 and 65.6 mmol MB m− 2) than converted cedar (6.80 kg SOC m− 2 and 38.4 mmol MB m− 2) or pine (5.87 kg SOC m− 2 and 39.9 mmol MB m− 2) forest. Losses of AMF biomass occurred on conversion of native grasslands to pine forest. Stocks of SF biomass only differed with vegetation type in topsoil. Conclusions: Conversion of native grasslands to cedar or pine forest increased topsoil (0 − 10 cm) SOC storage due to needle litter accumulation. Conversion of native grasslands to forests decreased subsoil (10 − 300 cm) SOC stocks and had replaced, by increasing depth, 30 to 19% and 45 to 26% of grassland C with cedar and pine C, respectively. Changes in soil pH, nutrients, and soil microbial communities accelerated SOC turnover. [ABSTRACT FROM AUTHOR]

Background and aims: Ectomycorrhizal fungi synthesize carbohydrates and amino acids from recent photosynthate but can also assimilate soil-derived amino acids. The dynamics of different amino acid pools within fungi may differ because of differences in biosynthetic complexity and energetics. Methods : To study carbon dynamics between Pinus sylvestris and ectomycorrhizal fungi, 13CO2 pulses were traced for 97 days post-labeling into amino acids and structural carbon of Cortinarius semisanguineus and Lactarius rufus sporocarps. Results: Without 13C labeling, amino acid δ13C was higher in Cortinarius than Lactarius, which suggested uptake of older, soil-derived amino acids by Cortinarius. In stepwise regression, 13C labeling in amino acids was 59 ± 2% of that in structural carbon. This first amino acid pool derived from recent plant sugars and peaked 16 days after 13CO2 labeling. The other 41% of amino acid carbon peaked on day 30, at 23% of the 13C enrichment of structural carbon, indicating two amino acid pools differing in 13C dynamics. Conclusion: I hypothesized that amino acids derived from recent plant sugars mostly had simple synthesis pathways (such as alanine, aspartic acid and glutamine), whereas the second pool reflected soil-derived or slow-turnover amino acids (such as lysine, leucine, and isoleucine) with multiple enzymatic steps to synthesis. Studies of amino acid use by ectomycorrhizal fungi should account for differences in dynamics and energetic costs between these two groups of amino acids. [ABSTRACT FROM AUTHOR]

Ectomycorrhizal fungi are among the most prevalent fungal partners of plants and can constitute up to one-third of forest microbial biomass. As mutualistic partners that supply nutrients, water, and pathogen defense, these fungi impact host plant health and biogeochemical cycling. Ectomycorrhizal fungi are also extremely diverse, and the community of fungal partners on a single plant host can consist of dozens of individuals. However, the factors that govern competition and coexistence within these communities are still poorly understood. In this study, we used in vitro competitive assays between five ectomycorrhizal fungal strains to examine how competition and pH affect fungal growth. We also tested the ability of evolutionary history to predict the outcomes of fungal competition. We found that the effects of pH and competition on fungal performance varied extensively, with changes in growth media pH sometimes reversing competitive outcomes. Furthermore, when comparing the use of phylogenetic distance and growth rate in predicting competitive outcomes, we found that both methods worked equally well. Our study further highlights the complexity of ectomycorrhizal fungal competition and the importance of considering phylogenetic distance, ecologically relevant traits, and environmental conditions in predicting the outcomes of these interactions. [ABSTRACT FROM AUTHOR]

The use of mycorrhized seedlings has been critical to the success of modern truffle cultivation, which nowadays supplies most European black truffles (Tuber melanosporum) to markets. Ascospore inoculation has been traditionally used to produce these seedlings, but little scientific information is publicly available on the inoculation methods applied or on the possibility of combining them. We evaluated the potential of sequential inoculation for the controlled colonization of holm oak fine roots by T. melanosporum , with two different nursery assays and a full factorial design. Three inoculation methods were sequentially applied: radicle inoculation, inoculation of the substrate in seedling trays and inoculation of the substrate in the final pot. Despite the differences in the results of the two assays, which suggest that cultivation conditions and/or the timing of nursery operations may influence the relative effectiveness of inoculation methods, the sequential application appeared as an effective and realistic alternative for commercial inoculation of holm oak seedlings with T. melanosporum. The increase in the amount of inoculum applied with each inoculation method improved the mycorrhizal colonization of seedlings, whereas separately none of the inoculation methods appeared clearly superior to the other ones. The depth distribution of truffle mycorrhizae pointed that the inoculation in the final pot was more effective than other methods in lower parts of the root system, whereas the early inoculation appeared more effective to reduce the occurrence of the opportunist ectomycorrhizal fungus Sphaerosporella brunnea. • The use of mycorrhized seedlings is critical to the success of truffle cultivation. • A sequential inoculation strategy to produce truffle mycorrhized seedlings was tested. • Root colonization by truffle increased with each inoculation method applied. • Inoculation methods affected mycorrhizae depth distribution and contaminant abundance. • Sequential inoculation could improve the quality of commercial truffle seedlings. [ABSTRACT FROM AUTHOR]

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Plant tolerance to aluminum (Al) toxicity can be enhanced by an ectomycorrhizal (ECM) fungus through biological filtering or physical blockage. To understand the roles of ECM colonization in Al absorption with regard to Al tolerance, Pinus massoniana seedlings were inoculated with either Lactarius deliciosus (L.:Fr.) Gray isolate 2 or Pisolithus tinctorius (Pers.) Coker et Couch isolate 715 and cultivated in an acid yellow soil with or without 1.0 mM Al3+ irrigation for 10 weeks. Biomass production, Al bioaccumulation and transport in seedlings colonized by the two ECM fungi were compared, and the three absorption kinetics (pseudo-first order, pseudo-second order and intraparticle diffusion) models used to evaluate variances in root Al3+ absorption capacity. Results show that both fungi increased aboveground biomass and Al tolerance of P. massoniana seedlings, but L. deliciosus 2 was more effective than P. tinctorius 715. Lower Al absorption capacity, fewer available active sites and decreased affinity and boundary layer thickness for Al3+, and higher Al accumulation and translocation contributed to the increased Al tolerance in the ECM-inoculated seedlings. These results advance our understanding of the mechanisms and strategies in plant Al-tolerance conferred by ECM fungi and show that inoculation with L. deliciosus will better enhance Al tolerance in P. massoniana seedlings used for forest plantation and ecosystem restoration in acidic soils, particularly in Southwest China and similar soils worldwide. [ABSTRACT FROM AUTHOR]

Pinus massoniana (Massion's pine), a pioneer tree species, exhibits restoration potential in polluted mining areas. However, the physiological and molecular mechanisms of ectomycorrhizal (ECM) fungi in Massion's pine adaptability to multiple-toxic-metal stress are still unclear. Hence, Massion's pine seedlings inoculated with two strains of C. geophilum, which were screened and isolated from a polluted mine area, were cultivated in mine soil for 90 days to investigate the roles of EMF in mediating toxic metal tolerance in host plants. The results showed that compared with the non-inoculation control, C. geophilum (CG1 and CG2) significantly promoted the biomass, root morphology, element absorption, photosynthetic characteristics, antioxidant enzyme activities (CAT, POD, and SOD), and proline content of Massion's pine seedlings in mine soil. C. geophilum increased the concentrations of Cr, Cd, Pb, and Mn in the roots of Massion's pine seedlings, with CG1 significantly increasing the concentrations of Pb and Mn by 246% and 162% and CG2 significantly increasing the concentrations of Cr and Pb by 102% and 78%. In contrast, C. geophilum reduced the concentrations of Cr, Cd, Pb, and Mn in the shoots by 14%, 33%, 27%, and 14% on average, respectively. In addition, C. geophilum significantly reduced the transfer factor (TF) of Cr, Cd, Pb, and Mn by 32–58%, 17–26%, 68–75%, and 18–64%, respectively, and the bio-concentration factor (BF) of Cd by 39–71%. Comparative transcriptomic analysis demonstrated that the differently expressed genes (DEGs) were mainly encoding functions involved in "transmembrane transport", "ion transport", "oxidation reduction process", "oxidative phosphorylation", "carbon metabolism", "glycolysis/gluconeogenesis", "photosynthesis", and "biosynthesis of amino acids." These results indicate that C. geophilum is able to mitigate toxic metals stress by promoting nutrient uptake, photosynthesis, and plant growth, thereby modulating the antioxidant system to reduce oxidative stress and reducing the transport and enrichment of toxic metals from the root to the shoot of Massion's pine seedlings. [ABSTRACT FROM AUTHOR]

Temperate forests are threatened by urbanization and fragmentation, with over 20% (118,300 km2 ) of U.S. forest land projected to be subsumed by urban land development. We leveraged a unique, well-characterized urban-to-rural and forest edge-to-interior gradient to identify the combined impact of these two land use changes—urbanization and forest edge creation—on the soil microbial community in native remnant forests. We found evidence of mutualism breakdown between trees and their fungal root mutualists [ectomycorrhizal (ECM) fungi] with urbanization, where ECM fungi colonized fewer tree roots and had less connectivity in soil microbiome networks in urban forests compared to rural forests. However, urbanization did not reduce the relative abundance of ECM fungi in forest soils; instead, forest edges alone led to strong reductions in ECM fungal abundance. At forest edges, ECM fungi were replaced by plant and animal pathogens, as well as copiotrophic, xenobiotic-degrading, and nitrogen-cycling bacteria, including nitrifiers and denitrifiers. Urbanization and forest edges interacted to generate new “suites” of microbes, with urban interior forests harboring highly homogenized microbiomes, while edge forest microbiomes were more heterogeneous and less stable, showing increased vulnerability to low soil moisture. When scaled to the regional level, we found that forest soils are projected to harbor high abundances of fungal pathogens and denitrifying bacteria, even in rural areas, due to the widespread existence of forest edges. Our results highlight the potential for soil microbiome dysfunction—including increased greenhouse gas production—in temperate forest regions that are subsumed by urban expansion, both now and in the future. [ABSTRACT FROM AUTHOR]

Cenococcum geophilum (C. geophilum) is a widely distributed ectomycorrhizal fungus that plays a crucial role in forest ecosystems worldwide. However, the specific ecological factors influencing its global distribution and how climate change will affect its range are still relatively unknown. In this study, we used the MaxEnt model optimized with the kuenm package to simulate changes in the distribution pattern of C. geophilum from the Last Glacial Maximum to the future based on 164 global distribution records and 17 environmental variables and investigated the key environmental factors influencing its distribution. We employed the optimal parameter combination of RM = 4 and FC = QPH, resulting in a highly accurate predictive model. Our study clearly shows that the mean temperature of the coldest quarter and annual precipitation are the key environmental factors influencing the suitable habitats of C. geophilum. Currently, appropriate habitats of C. geophilum are mainly distributed in eastern Asia, west‐central Europe, the western seaboard and eastern regions of North America, and southeastern Australia, covering a total area of approximately 36,578,300 km2 globally. During the Last Glacial Maximum and the mid‐Holocene, C. geophilum had a much smaller distribution area, being mainly concentrated in the Qinling‐Huaihe Line region of China and eastern Peninsular Malaysia. As global warming continues, the future suitable habitat for C. geophilum is projected to shift northward, leading to an expected expansion of the suitable area from 9.21% to 21.02%. This study provides a theoretical foundation for global conservation efforts and biogeographic understanding of C. geophilum, offering new insights into its distribution patterns and evolutionary trends. [ABSTRACT FROM AUTHOR]

Rhizosphere microbes, such as root-associated fungi, can improve plant access to soil resources, affecting plant health, productivity, and stress tolerance. While mycorrhizal associations are ubiquitous, plant–microbe interactions can be species specific. Here we show that the specificity of the effects of microbial symbionts on plant function can go beyond species level: colonization of roots by ectomycorrhizal fungi (EMF) of the genus Geopora has opposite effects on water uptake, and stomatal control of desiccation in drought tolerant and intolerant genotypes of pinyon pine (Pinus edulis Engelm.). These results demonstrate, for the first time, that microorganisms can have significant and opposite effects on important plant functional traits like stomatal control of desiccation that are associated with differential mortality and growth in nature. They also highlight that appropriate pairing of plant genotypes and microbial associates will be important for mitigating climate change impacts on vegetation. [ABSTRACT FROM AUTHOR]

Summary: The continuous imbalance between nitrogen (N) and phosphorus (P) deposition is expected to shift many ecosystems from N‐ to P limitation. Extraradical hyphae of ectomycorrhizal (ECM) fungi play important roles in plant nutrient acquisition under nutrient deficiency. However, whether and how ECM hyphae enhance soil P availability to alleviate N‐induced P deficiency remains unclear.We investigated the impacts of ECM hyphae on transformations among different soil P fractions and underlying mechanisms under N deposition in two ECM‐dominated forests.Ectomycorrhizal hyphae enhanced soil P availability under N addition by stimulating mineralization of organic P (Po) and desorption and solubilization of secondary mineral P, as indicated by N‐induced increase in positive hyphal effect on plant‐available P pool and negative hyphal effects on Po and secondary mineral P pools. Moreover, ECM hyphae increased soil phosphatase activity and abundance of microbial genes associated with Po mineralization and inorganic P solubilization, while decreasing concentrations of Fe/Al oxides.Our results suggest that ECM hyphae can alleviate N‐induced P deficiency in ECM‐dominated forests by regulating interactions between microbial and abiotic factors involved in soil P transformations. This advances our understanding of plant acclimation strategies via mediating plant–mycorrhiza interactions to sustain forest production and functional stability under changing environments. [ABSTRACT FROM AUTHOR]

The interactions between roots and mycorrhizal fungi are critical for our understanding of the multidimensional root economics space. Our knowledge on their relationships comes mainly from arbuscular mycorrhizal (AM) plants, and less is known about how roots are coordinated with ectomycorrhizal (ECM) fungal communities, especially in ECM‐dominated alpine forests that are highly sensitive to climate change worldwide.Here, we investigated the coordination between roots and ECM fungi and their drivers by measuring multiple root traits, ECM fungal composition and environmental factors of 47 coniferous populations across the alpine coniferous forests on the Tibetan Plateau.Our results reveal two independent fine‐root trait dimensions, that is root foraging dimension and root uptake dimension, which are represented by root diameter‐specific root length, root tissue density‐root N concentration. Importantly, the hyphal exploration type based ECM foraging correlated significantly with both root foraging and root uptake dimension. Further, in the low temperature plateau, it is precipitation‐induced changes in soil moisture, soil nutrients and pH that drive the proportion of longer‐distance hyphal exploration types to increase with higher root foraging by higher specific root length, and to decrease with higher uptake by higher root N concentration.Synthesis. The coordination of multidimensional root traits with ECM fungi differs greatly from the well‐recognized pattern in AM plants that mycorrhizal fungi connect predominantly with root foraging and that roots and mycorrhizal fungi are temperature sensitive. These findings provide a new insight for our holistic understanding of how roots and mycorrhizal fungi vary collaboratively and hence driving plant community assembly and responses to the changing climate. [ABSTRACT FROM AUTHOR]

Despite growing interest in fungal necromass decomposition due to its importance in soil carbon retention, whether a consistent group of microorganisms is associated with decomposing necromass remains unresolved. Here, we synthesize knowledge on the composition of the bacterial and fungal communities present on decomposing fungal necromass from a variety of fungal species, geographic locations, habitats, and incubation times. We found that there is a core group of both bacterial and fungal genera (i.e. a core fungal necrobiome), although the specific size of the core depended on definition. Based on a metric that included both microbial frequency and abundance, we demonstrate that the core is taxonomically and functionally diverse, including bacterial copiotrophs and oligotrophs as well as fungal saprotrophs, ectomycorrhizal fungi, and both fungal and animal parasites. We also show that the composition of the core necrobiome is notably dynamic over time, with many core bacterial and fungal genera having specific associations with the early, middle, or late stages of necromass decomposition. While this study establishes the existence of a core fungal necrobiome, we advocate that profiling the composition of fungal necromass decomposer communities in tropical environments and other terrestrial biomes beyond forests is needed to fill key knowledge gaps regarding the global nature of the fungal necrobiome. [ABSTRACT FROM AUTHOR]

A new species in genus Inocybe is described and illustrated from Himalayan Moist Temperate forests of Pakistan. It is characterized by fibrillose, conical to convex, umbonate, brown to dark brown pileus, non‐pruinose, fibrillose stipe with whitish tomentum at base, basidiospores smooth and larger (9.0 × 5.2 µm) and thicker caulocystidia (upto 21 m) as compared to sister species, Inocybe demetris. Phylogenetic analyses of nuc rDNA region encompassing the internal transcribed spacers 1 and 2 along with 5.8S rDNA (ITS) and nuc 28S rDNA D1–D2 domains (28S) also confirmed its novelty. [ABSTRACT FROM AUTHOR]

In many species-rich subtropical and tropical forests, the canopy is dominated by trees that form symbioses with ectomycorrhizal fungi, while understorey trees typically form symbioses with arbuscular mycorrhizal fungi. We propose a virtuous phosphorus acquisition hypothesis to explain this structure. This hypothesis is based on evidence that ectomycorrhizal fungi are better equipped than arbuscular mycorrhizal fungi to acquire growth-limiting phosphorus from organic forms in soil through the production of enzymes and exudates. Ectomycorrhizal saplings also gain more benefit from the formation of fungal networks with neighbouring adult plants, which also suppress infection by pathogens. Canopy dominance provides plants with the opportunity to capture more carbon from the atmosphere and fuel these below-ground nutrient-foraging activities. Subtropical and tropical forests in Asia often comprise canopy dominant trees that form symbioses with ectomycorrhizal fungi, and species-rich understorey trees that form symbioses with arbuscular mycorrhizal fungi. We propose a virtuous phosphorus acquisition hypothesis to explain this distinct structure. The hypothesis is based on (i) seedlings being rapidly colonised by ectomycorrhizal fungi from established mycelial networks that generates positive feedback and resistance to pathogens, (ii) ectomycorrhizal fungi having evolved a suite of morphological, physiological, and molecular traits to enable them to capture phosphorus from a diversity of chemical forms, including organic forms, and (iii) allocation of photosynthate carbon from adult host plants to provide the energy needed to undertake these processes. [ABSTRACT FROM AUTHOR]

Pine wilt disease (PWD), caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus, poses a severe threat to pine forests worldwide. However, the understanding of the impact of PWD on the host microbiome remains limited. This study aimed to investigate the structure and function of the fungal community associated with Pinus thunbergii fine roots and the rhizosphere fungi and bacteria of the tree naturally infected by PWN and the healthy tree. We employed high-throughput sequencing in conjunction with functional prediction tools (Functional Annotation of Prokaryotic Taxa and Fungi Functional Guild) and soil enzyme activity measurements between the two treatments (disease vs. health). The results showed that PWD significantly decreased the activity of β-cellobiosidase (CEL) and β-glucosidase (GLS) enzymes involved in carbon cycling in the rhizosphere (p < 0.05). However, PWD did not alter the diversity of rhizosphere bacteria and fine root fungi, but it did cause a significant decrease in the richness of rhizosphere fungi (p < 0.05). Moreover, PWD significantly reduced the abundance of Actinobacteria and genus Gaiella (p < 0.05). Functionally, bacterial intracellular parasites exhibited a higher abundance in the rhizosphere after PWN infection, whereas ureolysis showed a lower abundance (p < 0.05). Fungal saprotroph–symbiotroph exhibited a higher abundance in the rhizosphere after PWN infection, whereas symbiotroph showed a lower abundance (p < 0.05). Additionally, it led to a significant reduction in the infection rate of ectomycorrhizal fungi (p < 0.05). Infected host fine root exhibited higher abundance of pathotroph–symbiotroph, whereas symbiotroph had a lower abundance (p < 0.05). These findings provided valuable insights into the interactions between pine wilt disease, plant microbial communities, and soil enzyme activity. [ABSTRACT FROM AUTHOR]

Bareroot European beech (Fagus sylvatica L.) seedlings are frequently used in reforestation programs in Central Europe. However, beech outplanting is often unsuccessful due to drought stress. In this study, the effects of a simulated water deficit and of a hydrogel and ectomycorrhizal fungi (EMF) application were estimated on the development of 1 + 1 beech seedlings. The roots of 1-year-old bareroot seedlings were treated with the additives at the time of transplanting to pots in spring and then exposed to the whole growing season under different watering regimes: (i) full watering (FW; volumetric water content 70%), (ii) reduced watering (RW; 40%), (iii) periodic watering (PW; substrate rewetted to 70% after drying), and (iv) no watering (NW). Almost all FW seedlings survived the whole growing season, whereas all NW seedlings died after 17 weeks of desiccation. The survival and growth of FW and NW seedlings were significantly higher and lower, respectively, than those under both PW and RW treatments. The additives significantly increased survival in RW seedlings only but had no effect on growth. A promoting effect of FW on the chlorophyll a fluorescence parameters was found. The number and EMF colonization of the short roots were significantly lower in FW seedlings compared to the other watering treatments. The additives did not affect these parameters. The occurrence of neither treatment-specific EMF root morphotype nor fungi applied in the inoculum and traced by molecular analysis indicated the formation of ectomycorrhizas with native EMF in all treatments. The seedlings in the water-deficient treatments exhibited higher foliar nutrient concentrations than FW seedlings. The additives increased the concentration of nutrients in PW and phosphorus in NW seedlings. The results suggest the significant effect of the water supply, but a weaker effect of the additives tested on beech seedling development under experimental conditions. [ABSTRACT FROM AUTHOR]

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Climate change can affect forest ecosystems, especially through an increase of extreme events. In order to verify whether mycosilvicultural practices could mitigate the effects of climate change, productivity of Boletus edulis in Abies alba managed plantations was correlated to intense rainfall and temperature peaks during three years. Fungal productivity in each of the 21 days following an extreme climatic event was considered. Results showed that sudden increases in maximum temperature seemed to have an inhibitory effect on B. edulis productivity in sites with no or modest thinning. In sites with heavy thinning, productivity seemed to be favoured by high temperatures, starting from the twentieth day following the extreme event. Mycosilviculture may mitigate the climate change effects; however, further studies are needed to verify how climate-dominated effects can be altered by local factors and how ecological relationship between B. edulis and forest ecosystem will be affected.

Social Impact Statement Botanic gardens offer unique opportunities for unravelling responses of plant life to climate change. Despite investigations into their aboveground sphere, the belowground realm is usually neglected. Cambridge University Botanic Garden now illuminates the hidden world of one of the most sought‐after culinary delicacies—the Burgundy truffle. The garden's plant diversity, the serendipity of a truffle dog, and our curiosity‐driven research agenda reveal insights into 278 truffle fruitbodies that grew symbiotically with an unusually high number of host species. Our study reinforces the power of botanic gardens to disentangle ecosystem processes and emphasizes the proximity of scientific and public interests in truffles.

Within the forest community, competition and facilitation between adjacent-growing conspecific and heterospecific plants are mediated by interactions involving common mycorrhizal networks. The ability of plants to alter their neighbors microbiome is well documented, but the molecular biology of plant-fungal interactions during competition and facilitation has not been previously examined. We used a common soil-plant bioassay experiment to study molecular plant-microbial interactions among rhizosphere communities associated with Pinus taeda (native host) and Populus trichocarpa (non-native host). Gene expression of interacting fungal and bacterial rhizosphere communities was compared among three plant-pairs: Populus growing with Populus, Populus with Pinus, and Pinus with Pinus. Our results demonstrate that heterospecific plant partners affect the assembly of root microbiomes, including the changes in the structure of host specific community. Comparative metatranscriptomics reveals that several species of ectomycorrhizal fungi (EMF) and saprotrophic fungi exhibit different patterns of functional and regulatory gene expression with these two plant hosts. Heterospecific plants affect the transcriptional expression pattern of EMF host-specialists (e.g., Pinus-associated Suillus spp.) on both plant species, mainly including the genes involved in the transportation of amino acids, carbohydrates, and inorganic ions. Alteration of root microbiome by neighboring plants may help regulate basic plant physiological processes via modulation of molecular functions in the root microbiome.

Suillus bovinus is a wild edible ectomycorrhizal fungus with important economic and ecological value, which often forms an ectomycorrhiza with pine trees. We know little about the mechanisms associated with the metabolism and symbiosis of S. bovinus and its effects on the nutritional value. In this study, the whole-genome sequencing of S. bovinus was performed using Illumina, HiFi, and Hi-C technologies, and the sequencing data were subjected to genome assembly, gene prediction, and functional annotation to obtain a high-quality chromosome-level genome of S. bovinus. The final assembly of the S. bovinus genome includes 12 chromosomes, with a total length of 43.03 Mb, a GC content of 46.58%, and a contig N50 size of 3.78 Mb. A total of 11,199 coding protein sequences were predicted from genome annotation. The S. bovinus genome contains a large number of small secreted proteins (SSPs) and genes that encode enzymes related to carbohydrates, as well as genes related to terpenoids, auxin, and lipochitooligosaccharides. These genes may contribute to symbiotic processes. The whole-genome sequencing and genetic information provide a theoretical basis for a deeper understanding of the mechanism of the mycorrhizal symbiosis of S. bovinus and can serve as a reference for comparative genomics of ectomycorrhizal fungi.

Each gram of rich soil can harbor 100 million to a billion microorganisms, meaning every inch of our soil is alive (Raynaud and Nunan 2014) (Fig. 1). These underground organisms keep soil healthy. Balancing the community of microbes can benefit plant yield, plant health, and soil sustainability. While it is recognized that many soil microbes perform key roles in crop productivity, the importance of these underground activities is easily overlooked because of their small size. By focusing on a specific group of microbes living on or near plant roots, this publication provides understanding for these questions: Who are these microbes and how do they improve plant and soil health?

ABSTRACT To date, the ectomycorrhizal (EM) fungi community has been widely investigated with aging plantations affected by the pedologic factors. However, knowledge on the effects of phenology induced by climatic factors across the age range remains poorly understood on an intra-annual scale. Here, we sampled the fine roots of Mongolian pine (Pinus sylvestris var. mongolica) plantations at different stages of the growing season (from April to September) across three stand ages (27, 34, and 44 yr) in the Mu Us Desert, Northwest China. We aim to disentangle the community composition and structure of EM fungi, as well as the impact of climate on EM fungi. We observed that the 173 distinct EM fungal operational taxonomic units (OTUs) were identified. Geopora, Inocybe, Tomentella, and Tuber were the most frequent, and their dominance was maintained as stand aging. The richness and community composition were not significantly different with stand aging (P > 0.05). Host phenology and stand age are two important factors that have shaped the EM fungal community. The growing stage affected the beta diversity of the EM fungal community more than stand age, and this variation of the EM fungal community was closely related to seasonal climate, particularly precipitation. This improved information will provide a theoretical basis for the reforestation and rehabilitation of the Mongolian pine plantations using mycorrhizal techniques. IMPORTANCE Ectomycorrhizal (EM) fungi are particularly important for host plants in a desert ecosystem. With a high degree of plasticity, EM fungi are largely influenced by host plant and environmental variables and fundamentally contribute to the ability of individuals to adapt to environmental changes. Therefore, the EM fungi are important for Mongolian pine (Pinus sylvestris var. mongolica) plantation in a desert ecosystem. Although previous studies have concluded that multiple endogenous and exogenous processes ultimately lead to species-specific temporal patterns in EM fungal populations. We still neglect the effect of host phenology on EM fungal activity. The significance of our study is the interplay between climate-driven EM fungi and plant phenology.

Suillus luteus is a widespread edible ectomycorrhizal fungus that holds significant importance in both ecological and economic value. Mycoviruses are ubiquitous infectious agents hosted in different fungi, with some known to exert beneficial or detrimental effects on their hosts. However, mycoviruses hosted in ectomycorrhizal fungi remain poorly studied. To address this gap in knowledge, we employed next-generation sequencing (NGS) to investigate the virome of S. luteus. Using BLASTp analysis and phylogenetic tree construction, we identified 33 mycovirus species, with over half of them belonging to the phylum Lenarviricota, and 29 of these viruses were novel. These mycoviruses were further grouped into 11 lineages, with the discovery of a new negativesense single-stranded RNA viral family in the order Bunyavirales. In addition, our findings suggest the occurrence of cross-species transmission (CST) between the fungus and ticks, shedding light on potential evolutionary events that have shaped the viral community in different hosts. This study is not only the first study to characterize mycoviruses in S. luteus but highlights the enormous diversity of mycoviruses and their implications for virus evolution. [ABSTRACT FROM AUTHOR]

The interaction networks formed by ectomycorrhizal fungi (EMF) and their tree hosts, which are important to both forest recruitment and ecosystem carbon and nutrient retention, may be particularly susceptible to climate change at the boreal-temperate forest ecotone where environmental conditions are changing rapidly. Here, we quantified the compositional and functional trait responses of EMF communities and their interaction networks with two boreal (Pinus banksiana and Betula papyrifera) and two temperate (Pinus strobus and Quercus macrocarpa) hosts to a factorial combination of experimentally elevated temperatures and reduced rainfall in a long-term open-air field experiment. The study was conducted at the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment in Minnesota, USA, where infrared lamps and buried heating cables elevate temperatures (ambient, +3.1 °C) and rain-out shelters reduce growing season precipitation (ambient, ~30% reduction). EMF communities were characterized and interaction networks inferred from metabarcoding of fungal-colonized root tips. Warming and rainfall reduction significantly altered EMF community composition, leading to an increase in the relative abundance of EMF with contact-short distance exploration types. These compositional changes, which likely limited the capacity for mycelial connections between trees, corresponded with shifts from highly redundant EMF interaction networks under ambient conditions to less redundant (more specialized) networks. Further, the observed changes in EMF communities and interaction networks were correlated with changes in soil moisture and host photosynthesis. Collectively, these results indicate that the projected changes in climate will likely lead to significant shifts in the traits, structure, and integrity of EMF communities as well as their interaction networks in forest ecosystems at the boreal-temperate ecotone. [ABSTRACT FROM AUTHOR]

Summary: Stable isotope signatures of fungal sporocarps have been instrumental in identifying carbon gains of chlorophyllous orchids from a fungal source. Yet, not all mycorrhizal fungi produce macroscopic sporocarps and frequently fungi of different taxa occur in parallel in orchid roots.To overcome this obstacle, we investigated stable isotope signatures of fungal pelotons extracted from orchid roots and compared these data to the respective orchid and reference plant tissues. Anoectochilus sandvicensis and Epipactis palustris represented specialized or unspecialized rhizoctonia‐associated orchids. Epipactis atrorubens and Epipactis leptochila are orchids considered ectomycorrhiza‐associated with different preferences for Basidio‐ and Ascomycota.13C enrichment of rhizoctonia pelotons was minor compared with plant tissues and significantly lower than enrichments of pelotons from ectomycorrhizal Epipactis species. 15N values of pelotons from E. leptochila and E. atrorubens showed similar patterns as known for respective sporocarps of ectomycorrhizal Ascomycota and Basidiomycota, however, with an offset towards lower 15N enrichments and nitrogen concentrations.Our results suggest an explicit fungal nutrition source of orchids associated with ectomycorrhizal fungi, whereas the low 13C enrichment in rhizoctonia‐associated orchids and fungal pelotons hamper the detection of carbon gains from fungal partners. 15N isotopic pattern of orchids further suggests a selective transfer of 15N‐enriched protein‐nitrogen into orchids. [ABSTRACT FROM AUTHOR]

These signatures have been shown to reflect the ecophysiology of fungi and demonstrate that fungi that can utilize organic nitrogen exhibit higher SP 15 sp N than those fungi restricted to mineral nitrogen sources (Gebauer & Taylor, [4]; Lilleskov I et al i ., [14]). Keywords: arbuscular mycorrhizal fungi; carbon; DNA sequencing; ITS2; mycoheterotrophy; nitrogen; rhizoctonia EN arbuscular mycorrhizal fungi carbon DNA sequencing ITS2 mycoheterotrophy nitrogen rhizoctonia 1166 1172 7 07/17/23 20230815 NES 230815 Data availability Isotope abundance data are available in the Supporting Information. For the orchid-associated fungi, hyphae are only slightly enriched in SP 13 sp C in relation to both reference and orchid plants, remaining unclear whether these orchids gain C from the associated fungi based on these results. Yet, values of SP 13 sp C and SP 15 sp N are poorly known for arbuscular mycorrhizal fungi (but see e.g. Courty I et al i ., [1]; Suetsugu I et al i ., [24], for isotope values of fungal spores), and the orchid-associated fungi known as "rhizoctonia" in natural conditions. [Extracted from the article]

Species of Amanita sect. Vaginatae (Fr.) Quél. are challenging to delimitate due to the morphological similarity or morphostasis among different taxa. In this study, a multi-locus (nuc rDNA region encompassing the internal transcribed spacers 1 and 2 with the 5.8S rDNA, the D1–D3 domains of nuc 28S rDNA, partial sequences of translation elongation factor 1-a, and the second largest subunit of RNA polymerase II) phylogeny was employed to investigate the species diversity of the section in eastern China. Sixteen species were recognized, including four new species; namely, A. circulata, A. multicingulata, A. orientalis, and A. sinofulva. They were documented with illustrated descriptions, ecological evidence, and comparisons with similar species. A key to the species of the section from eastern China is provided. [ABSTRACT FROM AUTHOR]

Fungi of the order Boletales are extremely important in both ecology and economy, since most of them are ectomycorrhizal fungi, which play vital roles in maintaining forest ecosystems, water and soil protection, vegetation restoration and so on. Although previous studies have shown that this order has a very high species diversity in China, there are few reports on the species diversity of boletes in Jiangxi Province, China. Based on morphological (macroscopic and microscopic morphological characteristics) and phylogenetic analyses (ITS, LSU, and TEF1-α sequences), in this study, the wild boletes in Jiangxi Province were investigated, and five new species are described: Austroboletus albus, Xanthoconium violaceipes, Xanthoconium violaceofuscum, Xerocomus rutilans and Xerocomus subsplendidus. Descriptions and hand drawings of the new species are presented. [ABSTRACT FROM AUTHOR]

Background and Aims: In temperate forests, fungi are the main actors in leaf litter decomposition. Still, we have minimal knowledge of their influence on changes in leaf litter chemistry. Thus, we aimed to determine the main drivers behind leaf litter chemical transformation during decomposition. Methods: We monitored the development of fungal communities, extracellular enzyme activities, and litter chemical properties during a long-term (768 days) transplantation experiment of two chemically-contrasted intraspecific oak leaf litters. Results: Initial differences in substrate chemistry between native and transplanted Quercus petraea litters incubated at the same forest site largely persisted throughout the decomposition process, indicating that initial substrate quality constrained litter chemical transformation. The two litter types also maintained distinct fungal communities despite similar enzyme profiles. This suggests that fungi act more as constrained mediators rather than controllers of chemical changes during litter decay. Further, the litter elemental (i.e., nutrient composition) and organic (i.e., lignin and carbohydrate composition) chemistries tended respectively to diverge and converge over time between the native and transplanted litter types. Conclusion: The results highlight that leaf litter chemical transformation is a dynamic process mediated—but not oriented— by fungal communities. The factors influencing changes in leaf litter's organic and elemental chemical properties may be decoupled, with potentially contrasting consequences on forest carbon stocks and soil fertility. [ABSTRACT FROM AUTHOR]