The recovery of the soil ecosystem after severe disturbances, such as coal-mining activities, depends on both abiotic and biotic improvements. This study assessed the influence of arbuscular mycorrhizal (AM) fungal consortia on microbial community dynamics across two stages of soil recovery - 2 years (2Y) and 15 years (15Y) post-disturbance - using a secondary succession forest (SSR) as a reference. We analyzed bacterial community composition via 16 S rRNA gene amplicon sequencing and evaluated key soil quality indicators. While inoculation with AM fungal consortia had minimal effects on most soil parameters, significant differences were observed between recovery stages. The 15Y recovery site exhibited improved soil structure, microbial activity, and aggregate stability compared to the 2Y site, highlighting the importance of long-term restoration. However, potential overlap in ecological roles among native microorganisms likely mitigates the impact of AMF inoculation. These findings suggest that AM fungal consortia alone may not drive immediate improvements in soil quality but can contribute to microbial interactions and recovery processes over time. This study highlights the complexity of soil restoration and emphasizes the need for strategies that integrate plant cover with microbial community development to enhance long-term ecosystem stability. Further research should explore the specific roles of AM fungi and native soil microbes in promoting soil structure and accelerating recovery.

• Keywords
• AM fungal consortia, Combined inoculation, Glomeromycota, Microbiome, Simplified community,
• MeSH
• Bacteria classification   genetics   isolation & purification   MeSH
• Ecosystem MeSH
• Microbiota * MeSH
• Mycorrhizae * physiology   MeSH
• Soil chemistry   MeSH
• Soil Microbiology * MeSH
• Coal Mining MeSH
• Coal MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Soil MeSH
• Coal MeSH

While orchids germinate thanks to carbon from their symbiotic fungi, variable carbon exchanges exist between adult orchids and their mycorrhizal fungi. Although some truly autotrophic orchids reward their fungi with carbon at adulthood, some species remain achlorophyllous and fully dependent on fungal carbon (mycoheterotrophy). Others are photosynthetic but also import fungal carbon: The so-called mixotrophic (MX) orchids rely on fungi of diverse taxonomy and ecology. Here, we classify MX nutrition of orchids into three types. Type I mixotrophy associates with diverse Asco- and Basidiomycota that are either saprotrophic or ectomycorrhizal, entailing enrichment of the orchids in 2H, 13C, and 15N. The two other types associate with rhizoctonias, a polyphyletic assemblage of Basidiomycotas that is ancestrally mycorrhizal in orchids. Type II mixotrophy associates with rhizoctonias that secondarily evolved into saprotrophic or ectomycorrhizal ecology, and thus enrich the orchid in 2H, 13C, and 15N. Type III mixotrophy, which remains debated, associates with rhizoctonias that have retained their ancestral lifestyle, that is saprotrophic and/or endophytic in nonorchids, and only entail orchid enrichment in 2H and 15N. Based on a case study of achlorophyllous variants in Mediterranean Ophrys and on published data, we discuss the distinct nature and research perspectives of type III mixotrophy.

• Keywords
• isotopic enrichment, mycoheterotrophy, mycorrhiza, rhizoctonia, saprotrophy,
• MeSH
• Basidiomycota physiology   MeSH
• Phylogeny MeSH
• Heterotrophic Processes MeSH
• Mycorrhizae physiology   MeSH
• Orchidaceae * microbiology   physiology   MeSH
• Symbiosis MeSH
• Carbon metabolism   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Carbon MeSH

Mycena s.s. is a ubiquitous mushroom genus whose members degrade multiple dead plant substrates and opportunistically invade living plant roots. Having sequenced the nuclear genomes of 24 Mycena species, we find them to defy the expected patterns for fungi based on both their traditionally perceived saprotrophic ecology and substrate specializations. Mycena displayed massive genome expansions overall affecting all gene families, driven by novel gene family emergence, gene duplications, enlarged secretomes encoding polysaccharide degradation enzymes, transposable element (TE) proliferation, and horizontal gene transfers. Mainly due to TE proliferation, Arctic Mycena species display genomes of up to 502 Mbp (2-8× the temperate Mycena), the largest among mushroom-forming Agaricomycetes, indicating a possible evolutionary convergence to genomic expansions sometimes seen in Arctic plants. Overall, Mycena show highly unusual, varied mosaic-like genomic structures adaptable to multiple lifestyles, providing genomic illustration for the growing realization that fungal niche adaptations can be far more fluid than traditionally believed.

• Keywords
• Arctic biology, TE proliferation, biotrophy–saprotrophy evolution, carbon degradation, fungal genomics, fungal guild, genome size diversity, plant-fungus interactions, root-associations, saprotrophs,
• MeSH
• Agaricales * genetics   MeSH
• Phylogeny MeSH
• Genome, Fungal * genetics   MeSH
• Evolution, Molecular MeSH
• Gene Transfer, Horizontal MeSH
• Plants microbiology   genetics   MeSH
• DNA Transposable Elements genetics   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• DNA Transposable Elements MeSH

Based on seven- and three-gene datasets, we discuss four alternative approaches for a reclassification of Fomitopsidaceae (Polyporales, Basidiomycota). After taking into account morphological diversity in the family, we argue in favour of distinguishing three genera only, viz. Anthoporia, Antrodia and Fomitopsis. Fomitopsis becomes a large genus with 128 accepted species, containing almost all former Fomitopsis spp. and most species formerly placed in Antrodia, Daedalea and Laccocephalum. Genera Buglossoporus, Cartilosoma, Daedalea, Melanoporia, Neolentiporus, alongside twenty others, are treated as synonyms of Fomitopsis. This generic scheme allows for morphologically distinct genera in Fomitopsidaceae, unlike other schemes we considered. We provide arguments for retaining Fomitopsis and suppressing earlier (Daedalea, Caloporus) or simultaneously published generic names (Piptoporus) considered here as its synonyms. Taxonomy of nine species complexes in the genus is revised based on ITS, ITS + TEF1, ITS + TEF1 + RPB1 and ITS + TEF1 + RPB2 datasets. In total, 17 species are described as new to science, 26 older species are reinstated and 26 currently accepted species names are relegated to synonymy. A condensed identification key for all accepted species in the genus is provided. Taxonomic novelties: New species: Fomitopsis algumicola Grebenc & Spirin, F. caseosa Vlasák & Spirin, F. cupressicola Vlasák, J. Vlasák Jr. & Spirin, F. derelicta Vlasák & Spirin, F. dollingeri Vlasák & Spirin, F. fissa Vlasák & Spirin, F. lapidosa Miettinen & Spirin, F. lignicolor Vlasák & Spirin, F. maculosa Miettinen & Spirin, F. pannucea Runnel & Spirin, F. perhiemata Viner & Spirin, F. purpurea Spirin & Ryvarden, F. retorrida Spirin & Kotiranta, F. solaris Rivoire, A.M. Ainsworth & Vlasák, F. tristis Miettinen & Spirin, F. tunicata Miettinen & Spirin, F. visenda Miettinen & Spirin. New combinations: Fomitopsis aculeata (Cooke) Spirin & Miettinen, F. aethalodes (Mont.) Spirin, F. alaskana (D.V. Baxter) Spirin & Vlasák, F. albidoides (A. David & Dequatre) Bernicchia & Vlasák, F. amygdalina (Berk. & Ravenel) Spirin & Vlasák, F. angusta (Spirin & Vlasák) Spirin & Vlasák, F. atypa (Lév.) Spirin & Vlasák, F. caespitosa (Murrill) Spirin & Miettinen, F. calcitrosa (Spirin & Miettinen) Spirin & Miettinen, F. circularis (B.K. Cui & Hai J. Li) Spirin, F. concentrica (G. Cunn.) M.D. Barrett, F. cyclopis (Miettinen & Spirin) Miettinen & Spirin, F. dickinsii (Berk. ex Cooke) Spirin, F. elevata (Corner) Spirin & Miettinen, F. eucalypti (Kalchbr.) Spirin, F. ferrea (Cooke) Spirin & Viner, F. flavimontis (Vlasák & Spirin) Vlasák & Spirin, F. foedata (Berk.) Spirin & Miettinen, F. gilvidula (Bres.) Spirin & Miettinen, F. glabricystidia (Ipulet & Ryvarden) Miettinen & Ryvarden, F. globispora (Ryvarden & Aime) Spirin, F. hartmannii (Cooke) M.D. Barrett & Spirin, F. hyalina (Spirin, Miettinen & Kotir.) Spirin & Miettinen, F. hypoxantha (Bres.) Spirin & Miettinen, F. incana (Lév.) Spirin & V. Malysheva, F. infirma (Renvall & Niemelä) Miettinen & Niemelä, F. juniperina (Murrill) Spirin & Vlasák, F. kuzyana (Pilát ex Pilát) Spirin & Vlasák, F. leioderma (Mont.) Spirin & Vlasak, F. leucaena (Y.C. Dai & Niemelä) Spirin & Miettinen, F. luzonensis (Murrill) Spirin & Miettinen, F. maculatissima (Lloyd) Spirin, F. madronae (Vlasák & Ryvarden) Vlasák & Ryvarden, F. malicola (Berk. & M.A. Curtis) Spirin, F. marchionica (Mont.) Spirin & Miettinen, F. marianii (Bres.) Spirin, Vlasák & Cartabia, F. mellita (Niemelä & Penttilä) Niemelä & Miettinen, F. microcarpa (B.K. Cui & Shun Liu) Spirin, F. micropora (B.K. Cui & Shun Liu) Spirin, F. modesta (Kuntze ex Fr.) Vlasák & Spirin, F. monomitica (Yuan Y. Chen) Spirin & Viner, F. morganii (Lloyd) Spirin & Vlasák, F. moritziana (Lév.) Spirin & Miettinen, F. neotropica (D.L. Lindner, Ryvarden & T.J. Baroni) Vlasák, F. nigra (Berk.) Spirin & Miettinen, F. nivosella (Murrill) Spirin & Vlasák, F. oboensis (Decock, Amalfi & Ryvarden) Spirin, F. oleracea (R.W. Davidson & Lombard) Spirin & Vlasák, F. philippinensis (Murrill) Spirin & Vlasák, F. primaeva (Renvall & Niemelä) Miettinen & Niemelä, F. psilodermea (Berk. & Mont.) Spirin & Vlasák, F. pulverulenta (Rivoire) Rivoire, F. pulvina (Pers.) Spirin & Vlasák, F. pulvinascens (Pilát ex Pilát) Niemelä & Miettinen, F. quercina (L.) Spirin & Miettinen, F. ramentacea (Berk. & Broome) Spirin & Vlasák, F. renehenticii (Rivoire, Trichies & Vlasák) Rivoire & Vlasák, F. roseofusca (Romell) Spirin & Vlasák, F. sagraeana (Mont.) Vlasák & Spirin, F. sandaliae (Bernicchia & Ryvarden) Bernicchia & Vlasák, F. sclerotina (Rodway) M.D. Barrett & Spirin, F. serialiformis (Kout & Vlasák) Vlasák, F. serialis (Fr.) Spirin & Runnel, F. serrata (Vlasák & Spirin) Vlasák & Spirin, F. squamosella (Bernicchia & Ryvarden) Bernicchia & Ryvarden, F. stereoides (Fr.) Spirin, F. subectypa (Murrill) Spirin & Vlasák, F. substratosa (Malençon) Spirin & Miettinen, F. tropica (B.K. Cui) Spirin, F. tumulosa (Cooke) M.D. Barrett & Spirin, F. tuvensis (Spirin, Vlasák & Kotir.) Spirin & Vlasák, F. uralensis (Pilát) Spirin & Miettinen, F. ussuriensis (Bondartsev & Ljub.) Spirin & Miettinen, F. variiformis (Peck) Vlasák & Spirin, F. yunnanensis (M.L. Han & Q. An) Spirin, Daedaleopsis candicans (P. Karst.) Spirin, Megasporoporia eutelea (Har. & Pat.) Spirin & Viner, Neofomitella hemitephra (Berk.) M.D. Barrett, Pseudophaeolus soloniensis (Dubois) Spirin & Rivoire, P. trichrous (Berk. & M.A. Curtis) Vlasák & Spirin. New synonyms: Antrodia bondartsevae Spirin, A. huangshanensis Y.C. Dai & B.K. Cui, A. taxa T.T. Chang & W.N. Chou, A. wangii Y.C. Dai & H.S. Yuan, Antrodiella subnigra Oba, Mossebo & Ryvarden, Antrodiopsis Audet, Boletus quercinus Schrad., Brunneoporus Audet, Buglossoporus Kotl. & Pouzar, Buglossoporus eucalypticola M.L. Han, B.K. Cui & Y.C. Dai, Caloporus P. Karst., Cartilosoma Kotlaba & Pouzar, Coriolus clemensiae Murrill, C. cuneatiformis Murrill, C. hollickii Murrill, C. parthenius Hariot & Pat., C. rubritinctus Murrill, Daedalea Pers., Daedalea allantoidea M.L. Han, B.K. Cui & Y.C. Dai, D. americana M.L. Han, Vlasák & B.K. Cui, D. radiata B.K. Cui & Hai J. Li, D. rajchenbergiana Kossmann & Drechsler-Santos, D. sinensis Lloyd, Daedalella B.K. Cui & Shun Liu, Dentiporus Audet, Flavidoporia Audet, Fomes subferreus Murrill, Fomitopsis cana B.K. Cui, Hai J. Li & M.L. Han, F. caribensis B.K. Cui & Shun Liu, F. cystidiata B.K. Cui & M.L. Han, F. ginkgonis B.K. Cui & Shun Liu, F. iberica Melo & Ryvarden, F. incarnata K.M. Kim, J.S. Lee & H.S. Jung, F. subfeei B.K. Cui & M.L. Han, F. subtropica B.K. Cui & Hai J. Li, Fragifomes B.K. Cui, M.L. Han & Y.C. Dai, Leptoporus epileucinus Pilát, Melanoporia Murrill, Neoantrodia Audet, Neolentiporus Rajchenb., Nigroporus macroporus Ryvarden & Iturr., Niveoporofomes B.K. Cui, M.L. Han & Y.C. Dai, Pilatoporus Kotl. & Pouzar, Piptoporus P. Karst., Polyporus aurora Ces., P. durescens Overh. ex J. Lowe, P. griseodurus Lloyd, Poria incarnata Pers., Pseudoantrodia B.K. Cui, Y.Y. Chen & Shun Liu, Pseudofomitopsis B.K. Cui & Shun Liu, Ranadivia Zmitr., Rhizoporia Audet, Rhodofomes Kotl. & Pouzar, Rhodofomitopsis B.K. Cui, M.L. Han & Y.C. Dai, Rhodofomitopsis pseudofeei B.K. Cui & Shun Liu, R. roseomagna Nogueira-Melo, A.M.S. Soares & Gibertoni, Rubellofomes B.K. Cui, M.L. Han & Y.C. Dai, Subantrodia Audet, Trametes fulvirubida Corner, T. lignea Murrill, T. lusor Corner, T. pseudodochmia Corner, T. subalutacea Bourdot & Galzin, T. supermodesta Ryvarden & Iturr., T. tuberculata Bres., Tyromyces multipapillatus Corner, T. ochraceivinosus Corner, T. palmarum Murrill, T. singularis Corner, T. squamosellus Núñez & Ryvarden, Ungulidaedalea B.K. Cui, M.L. Han & Y.C. Dai. Lectotypes: Hexagonia sulcata Berk., Polyporus castaneae Bourdot & Galzin, Poria incarnata Pers., Trametes subalutacea Bourdot & Galzin, Ungulina substratosa Malençon. Neotypes: Agaricus soloniensis Dubois, Boletus pulvinus Pers. Citation: Spirin V, Runnel K, Vlasák J, Viner I, Barrett MD, Ryvarden L, Bernicchia A, Rivoire B, Ainsworth AM, Grebenc T, Cartabia M, Niemelä T, Larsson K-H, Miettinen O (2024). The genus Fomitopsis (Polyporales, Basidiomycota) reconsidered. Studies in Mycology 107: 149-249. doi: 10.3114/sim.2024.107.03.

• Keywords
• brown-rot fungi, new taxa, phylogeny, polypores, taxonomy,
• Publication type
• Journal Article MeSH

Forests influence climate and mitigate global change through the storage of carbon in soils. In turn, these complex ecosystems face important challenges, including increases in carbon dioxide, warming, drought and fire, pest outbreaks and nitrogen deposition. The response of forests to these changes is largely mediated by microorganisms, especially fungi and bacteria. The effects of global change differ among boreal, temperate and tropical forests. The future of forests depends mostly on the performance and balance of fungal symbiotic guilds, saprotrophic fungi and bacteria, and fungal plant pathogens. Drought severely weakens forest resilience, as it triggers adverse processes such as pathogen outbreaks and fires that impact the microbial and forest performance for carbon storage and nutrient turnover. Nitrogen deposition also substantially affects forest microbial processes, with a pronounced effect in the temperate zone. Considering plant-microorganism interactions would help predict the future of forests and identify management strategies to increase ecosystem stability and alleviate climate change effects. In this Review, we describe the impact of global change on the forest ecosystem and its microbiome across different climatic zones. We propose potential approaches to control the adverse effects of global change on forest stability, and present future research directions to understand the changes ahead.

• MeSH
• Bacteria MeSH
• Nitrogen MeSH
• Ecosystem * MeSH
• Climate Change MeSH
• Forests MeSH
• Microbiota * MeSH
• Soil MeSH
• Plants MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Nitrogen MeSH
• Soil MeSH

Burgundy truffles are heterothallic ascomycetes that grow in symbiosis with trees. Despite their esteemed belowground fruitbodies, the species' complex lifecycle is still not fully understood. Here, we present the genetic patterns in three natural Burgundy truffle populations based on genotyped fruitbodies, ascospore extracts and ectomycorrhizal root tips using microsatellites and the mating-type locus. Distinct genetic structures with high relatedness in close vicinity were found for females (forming the fruitbodies) and males (fertilizing partner as inferred from ascospore extracts), with high genotypic diversity and annual turnover of males, suggesting that ephemeral male mating partners are germinating ascospores from decaying fruitbodies. The presence of hermaphrodites and the interannual persistence of a few males suggest that persistent mycelia may sporadically also act as males. Only female or hermaphroditic individuals were detected on root tips. At one site, fruitbodies grew in a fairy ring formed by a large female individual that showed an outward growth rate of 30 cm per year, with the mycelium decaying within the ring and being fertilized by over 50 male individuals. While fairy ring structures have never been shown for truffles, the genetics of Burgundy truffle populations support a similar reproductive biology as those of other highly prized truffles.

• MeSH
• Ascomycota * genetics   MeSH
• Humans MeSH
• Mycorrhizae * genetics   MeSH
• Life Cycle Stages MeSH
• Symbiosis MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Inter-kingdom belowground carbon (C) transfer is a significant, yet hidden, biological phenomenon, due to the complexity and highly dynamic nature of soil ecology. Among key biotic agents influencing C allocation belowground are ectomycorrhizal fungi (EMF). EMF symbiosis can extend beyond the single tree-fungus partnership to form common mycorrhizal networks (CMNs). Despite the high prevalence of CMNs in forests, little is known about the identity of the EMF transferring the C and how these in turn affect the dynamics of C transfer. Here, Pinus halepensis and Quercus calliprinos saplings growing in forest soil were labeled using a 13CO2 labeling system. Repeated samplings were applied during 36 days to trace how 13C was distributed along the tree-fungus-tree pathway. To identify the fungal species active in the transfer, mycorrhizal fine root tips were used for DNA-stable isotope probing (SIP) with 13CO2 followed by sequencing of labeled DNA. Assimilated 13CO2 reached tree roots within four days and was then transferred to various EMF species. C was transferred across all four tree species combinations. While Tomentella ellisii was the primary fungal mediator between pines and oaks, Terfezia pini, Pustularia spp., and Tuber oligospermum controlled C transfer among pines. We demonstrate at a high temporal, quantitative, and taxonomic resolution, that C from EMF host trees moved into EMF and that C was transferred further to neighboring trees of similar and distinct phylogenies.

• MeSH
• Quercus * microbiology   MeSH
• Plant Roots microbiology   MeSH
• Mycorrhizae * genetics   metabolism   MeSH
• Carbon Dioxide MeSH
• Soil MeSH
• Trees microbiology   MeSH
• Carbon metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Carbon Dioxide MeSH
• Soil MeSH
• Carbon MeSH

Arbuscular mycorrhizal (AM) fungi lack efficient exoenzymes to access organic nutrients directly. Nevertheless, the fungi often obtain and further channel to their host plants a significant share of nitrogen (N) and/or phosphorus from such resources, presumably via cooperation with other soil microorganisms. Because it is challenging to disentangle individual microbial players and processes in complex soil, we took a synthetic approach here to study 15N-labelled chitin (an organic N source) recycling via microbial loop in AM fungal hyphosphere. To this end, we employed a compartmented in vitro cultivation system and monoxenic culture of Rhizophagus irregularis associated with Cichorium intybus roots, various soil bacteria, and the protist Polysphondylium pallidum. We showed that upon presence of Paenibacillus sp. in its hyphosphere, the AM fungus (and associated plant roots) obtained several-fold larger quantities of N from the chitin than it did with any other bacteria, whether chitinolytic or not. Moreover, we demonstrated that adding P. pallidum to the hyphosphere with Paenibacillus sp. further increased by at least 65% the gain of N from the chitin by the AM fungus compared to the hyphosphere without protists. We thus directly demonstrate microbial interplay possibly involved in efficient organic N utilisation by AM fungal hyphae.

• MeSH
• Bacteria genetics   MeSH
• Nitrogen MeSH
• Phosphorus MeSH
• Plant Roots MeSH
• Mycorrhizae * MeSH
• Soil MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Nitrogen MeSH
• Phosphorus MeSH
• Soil MeSH

BACKGROUND: As in most land plants, the roots of orchids (Orchidaceae) associate with soil fungi. Recent studies have highlighted the diversity of the fungal partners involved, mostly within Basidiomycotas. The association with a polyphyletic group of fungi collectively called rhizoctonias (Ceratobasidiaceae, Tulasnellaceae and Serendipitaceae) is the most frequent. Yet, several orchid species target other fungal taxa that differ from rhizoctonias by their phylogenetic position and/or ecological traits related to their nutrition out of the orchid roots (e.g. soil saprobic or ectomycorrhizal fungi). We offer an evolutionary framework for these symbiotic associations. SCOPE: Our view is based on the 'Waiting Room Hypothesis', an evolutionary scenario stating that mycorrhizal fungi of land flora were recruited from ancestors that initially colonized roots as endophytes. Endophytes biotrophically colonize tissues in a diffuse way, contrasting with mycorrhizae by the absence of morphological differentiation and of contribution to the plant's nutrition. The association with rhizoctonias is probably the ancestral symbiosis that persists in most extant orchids, while during orchid evolution numerous secondary transitions occurred to other fungal taxa. We suggest that both the rhizoctonia partners and the secondarily acquired ones are from fungal taxa that have broad endophytic ability, as exemplified in non-orchid roots. We review evidence that endophytism in non-orchid plants is the current ecology of many rhizoctonias, which suggests that their ancestors may have been endophytic in orchid ancestors. This also applies to the non-rhizoctonia fungi that were secondarily recruited by several orchid lineages as mycorrhizal partners. Indeed, from our review of the published literature, they are often detected, probably as endophytes, in extant rhizoctonia-associated orchids. CONCLUSION: The orchid family offers one of the best documented examples of the 'Waiting Room Hypothesis': their mycorrhizal symbioses support the idea that extant mycorrhizal fungi have been recruited among endophytic fungi that colonized orchid ancestors.

• Keywords
• Ectomycorrhizal fungi, endophytism, mixotrophy, mycoheterotrophy, rhizoctonias, saprobic fungi,
• MeSH
• Waiting Rooms MeSH
• Endophytes MeSH
• Phylogeny MeSH
• Mycorrhizae * MeSH
• Orchidaceae * microbiology   MeSH
• Symbiosis MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH

Belowground litter derived from tree roots has been shown as a principal source of soil organic matter in coniferous forests. Fate of tree root necromass depends on fungal communities developing on the decaying roots. Local environmental conditions which affect composition of tree root mycobiome may also influence fungal communities developing on decaying tree roots. Here, we assessed fungal communities associated with decaying roots of Picea abies decomposing in three microhabitats: soil with no vegetation, soil with ericoid shrubs cover, and P. abies deadwood, for a 2-year period. Forest microhabitat showed stronger effect on structuring fungal communities associated with decaying roots compared to living roots. Some ericoid mycorrhizal fungi showed higher relative abundance on decaying roots in soils under ericoid shrub cover, while saprotrophic fungi had higher relative abundance in roots decomposing inside deadwood. Regardless of the studied microhabitat, we observed decline of ectomycorrhizal fungi and increase of endophytic fungi during root decomposition. Interestingly, we found substantially more fungal taxa with unknown ecology in late stages of root decomposition, indicating that highly decomposed roots may represent so far overlooked niche for soil fungi. Our study shows the importance of microhabitats on the fate of the decomposing spruce roots.

• Keywords
• Norway spruce, dark septate endophytes, forest ecosystem, forest microhabitats, fungal communities, root litter, soil organic matter, stem decapitation,
• Publication type
• Journal Article MeSH