The ectomycorrhizal (EcM) symbiosis involves a large number of plant and fungal taxa worldwide During studies on EcM diversity, numerous misidentifications, and contradictory reports on EcM status have been published This review aims to: (1) critically assess the current knowledge of the fungi involved in the EcM by integrating data from axenic synthesis trials, anatomical, molecular, and isotope studies; (2) group these taxa into monophyletic lineages based on molecular sequence data and published phylogenies; (3) investigate the trophic status of sister taxa to EcM lineages; (4) highlight other potentially EcM taxa that lack both information on EcM status and DNA sequence data; (5) recover the main distribution patterns of the EcM fungal lineages in the world Based on critically examining original reports, EcM lifestyle is proven in 162 fungal genera that are supplemented by two genera based on isotopic evidence and 52 genera based on phylogenetic data Additionally, 33 genera are highlighted as potentially EcM based on habitat, although their EcM records and DNA sequence data are lacking Molecular phylogenetic and identification studies suggest that EcM symbiosis has arisen independently and persisted at least 66 times in fungi, in the Basidiomycota, Ascomycota, and Zygomycota The orders Pezizales, Agaricales, Helotiales, Boletales, and Cantharellales include the largest number of EcM fungal lineages Regular updates of the EcM lineages and genera therein can be found at the UNITE homepage http://uniteutee/EcM_lineages The vast majority of EcM fungi evolved from humus and wood saprotrophic ancestors without any obvious reversals Herbarium records from 11 major biogeographic regions revealed three main patterns in distribution of EcM lineages: (1) Austral; (2) Panglobal; (3) Holarctic (with or without some reports from the Austral or tropical realms) The holarctic regions host the largest number of EcM lineages; none are restricted to a tropical distribution with Dipterocarpaceae and Caesalpiniaceae hosts We caution that EcM-dominated habitats and hosts in South America, Southeast Asia, Africa, and Australia remain undersampled relative to the north temperate regions In conclusion, EcM fungi are phylogenetically highly diverse, and molecular surveys particularly in tropical and south temperate habitats are likely to supplement to the present figures Due to great risk of contamination, future reports on EcM status of previously unstudied taxa should integrate molecular identification tools with axenic synthesis experiments, detailed morphological descriptions, and/or stable isotope investigations We believe that the introduced lineage concept facilitates design of biogeographical studies and improves our understanding about phylogenetic structure of EcM fungal communities

Ectomycorrhizal lifestyle in fungi: global diversity, distribution, and evolution of phylogenetic lineages

https://cyberleninka.org/article/n/1212592.pdf

Lineages of ectomycorrhizal fungi revisited: Foraging strategies and novel lineages revealed by sequences from belowground

There is growing evidence of the importance of extramatrical mycelium (EMM) of mycorrhizal fungi in carbon (C) cycling in ecosystems. However, our understanding has until recently been mainly based on laboratory experiments, and knowledge of such basic parameters as variations in mycelial production, standing biomass and turnover as well as the regulatory mechanisms behind such variations in forest soils is limited. Presently, the production of EMM by ectomycorrhizal (EM) fungi has been estimated at similar to 140 different forest sites to be up to several hundreds of kg per ha per year, but the published data are biased towards Picea abies in Scandinavia. Little is known about the standing biomass and turnover of EMM in other systems, and its influence on the C stored or lost from soils. Here, focussing on ectomycorrhizas, we discuss the factors that regulate the production and turnover of EMM and its role in soil C dynamics, identifying important gaps in this knowledge. C availability seems to be the key factor determining EMM production and possibly its standing biomass in forests but direct effects of mineral nutrient availability on the EMM can be important. There is great uncertainty about the rate of turnover of EMM. There is increasing evidence that residues of EM fungi play a major role in the formation of stable N and C in SOM, which highlights the need to include mycorrhizal effects in models of global soil C stores.

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The production and turnover of extramatrical mycelium of ectomycorrhizal fungi in forest soils: role in carbon cycling

Knowledge of the relationships and thus the classification of fungi, has developed rapidly with increasingly widespread use of molecular techniques, over the past 10–15 years, and continues to accelerate. Several genera have been found to be polyphyletic, and their generic concepts have subsequently been emended. New names have thus been introduced for species which are phylogenetically distinct from the type species of particular genera. The ending of the separate naming of morphs of the same species in 2011, has also caused changes in fungal generic names. In order to facilitate access to all important changes, it was desirable to compile these in a single document. The present article provides a list of generic names of Ascomycota (approximately 6500 accepted names published to the end of 2016), including those which are lichen-forming. Notes and summaries of the changes since the last edition of ‘Ainsworth & Bisby’s Dictionary of the Fungi’ in 2008 are provided. The notes include the number of accepted species, classification, type species (with location of the type material), culture availability, life-styles, distribution, and selected publications that have appeared since 2008. This work is intended to provide the foundation for updating the ascomycete component of the “Without prejudice list of generic names of Fungi” published in 2013, which will be developed into a list of protected generic names. This will be subjected to the XIXth International Botanical Congress in Shenzhen in July 2017 agreeing to a modification in the rules relating to protected lists, and scrutiny by procedures determined by the Nomenclature Committee for Fungi (NCF). The previously invalidly published generic names Barriopsis, Collophora (as Collophorina), Cryomyces, Dematiopleospora, Heterospora (as Heterosporicola), Lithophila, Palmomyces (as Palmaria) and Saxomyces are validated, as are two previously invalid family names, Bartaliniaceae and Wiesneriomycetaceae. Four species of Lalaria, which were invalidly published are transferred to Taphrina and validated as new combinations. Catenomycopsis Tibell & Constant. is reduced under Chaenothecopsis Vain., while Dichomera Cooke is reduced under Botryosphaeria Ces. & De Not. (Art. 59).

Notes for genera: Ascomycota

Fungal secondary metabolites as modulators of interactions with insects and other arthropods.

Ecological benefits of the alley cropping agroforestry system in sensitive regions of Europe

Ectomycorrhizal (ECM) communities were assessed on a 720 m2 plot along a chronosequence of red oak (Quercus rubra) stands on a forest reclamation site with disturbed soil in the lignite mining area of Lower Lusatia (Brandenburg, Germany). Adjacent to the mining area, a red oak reference stand with undisturbed soil was investigated reflecting mycorrhiza diversity of the intact landscape. Aboveground, sporocarp surveys were carried out during the fruiting season in a 2-week interval in the years 2002 and 2003. Belowground, ECM morphotypes were identified by comparing sequences of the internal transcribed spacer regions from nuclear rDNA with sequences from the GenBank database. Fifteen ECM fungal species were identified as sporocarps and 61 belowground as determined by morphological/anatomical and molecular analysis of their ectomycorrhizas. The number of ECM morphotypes increased with stand age along the chronosequence. However, the number of morphotypes was lower in stands with disturbed soil than with undisturbed soil. All stands showed site-specific ECM communities with low similarity between the chronosequence stands. The dominant ECM species in nearly all stands was Cenococcum geophilum, which reached an abundance approaching 80% in the 21-year-old chronosequence stand. Colonization rate of red oak was high (>95%) at all stands besides the youngest chronosequence stand where colonization rate was only 15%. This supports our idea that artificial inoculation with site-adapted mycorrhizal fungi would enhance colonization rate of red oak and thus plant growth and survival in the first years after outplanting.

Ectomycorrhiza communities of red oak (Quercus rubra L.) of different age in the Lusatian lignite mining district, East Germany

Defensive strategies of soil fungi to prevent grazing by Folsomia candida (Collembola)

Relatively few ectomycorrhizal fungal species are known to form sclerotia. Usually, sclerotia are initiated at the extraradical mycelium. In this study, we present anatomical and ultrastructural evidence for the formation of sclerotia directly in the hyphal mantle of the mycorrhizal morphotype Pinirhiza sclerotia. A dark-pigmented fungal strain was isolated from Pinirhiza sclerotia and identified by molecular tools as Acephala macrosclerotiorum sp. nov., a close relative of Phialocephala fortinii s.l. As dark septate fungi are known to be mostly endophytic, resyntheses with Pinus sylvestris and A. macrosclerotiorum as well as Populus tremula × Populus tremuloides and A. macrosclerotiorum or P. fortinii s.l. were performed under axenic conditions. No mycorrhizas were found when hybrid aspen was inoculated with A. macrosclerotiorum or P. fortinii. However, A. macrosclerotiorum formed true ectomycorrhizas in vitro with P. sylvestris. Anatomical and ultrastructural features of this ectomycorrhiza are presented. The natural and synthesized ectomycorrhizal morphotypes were identical and characterized by a thin hyphal mantle that bore sclerotia in a later ontogenetic stage. The Hartig net was well-developed and grew up to the endodermis. To our knowledge, this is the first evidence at the anatomical and ultrastructural level that a close relative of P. fortinii s.l. forms true ectomycorrhizas with a coniferous host.

The ectomycorrhizal morphotype Pinirhiza sclerotia is formed by Acephala macrosclerotiorum sp. nov., a close relative of Phialocephala fortinii

In the last three decades high industrial nitrogen (N) emissions have led to eutrophication of a Scots pine stand (Pinus sylvestris [L.]) near Schwedt characterized by a broad cover of Calamagrostis epigejos [L.] Roth (Poaceae). In comparison to the relatively unimpacted control site (low N site), this high N site showed a remarkably low mycorrhizal frequency (percentage of mycorrhizas on total amount of root tips) with seasonal lows down to 27 %. At the low N site the highest number of mycorrhizal root tips was found in the organic layer. At the high N site the amount of mycorrhizas per soil volume was similar in both organic and mineral soil layers, and also significantly lower when compared to the amount at the low N site. The high N site revealed only nine mycorrhizal morphotypes instead of eighteen found at each sampling date at the control site. 80 % of the coenosis at the high N site were represented by only four morphotypes resulting in a low diversity. The seasonal decrease in the mycorrhizal frequency, the small amount of mycorrhizas and the low diversity suggest that the high N deposition at this site has reduced the ability of the pine trees to withstand natural stresses such as prolonged drought or frost periods. This corresponds well with the 42 % reduction in tree stocking density at the high N site compared to the low N site.

Jens Wöllecke

Papers

Ecological benefits of the alley cropping agroforestry system in sensitive regions of Europe

Ectomycorrhiza communities of red oak (Quercus rubra L.) of different age in the Lusatian lignite mining district, East Germany

Defensive strategies of soil fungi to prevent grazing by Folsomia candida (Collembola)

The ectomycorrhizal morphotype Pinirhiza sclerotia is formed by Acephala macrosclerotiorum sp. nov., a close relative of Phialocephala fortinii

Some Effects of N on Ectomycorrhizal Diversity of Scots Pine ( Pinus sylvestris L.) in Northeastern Germany