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Cahanovitc R, Livne-Luzon S, Angel R, Klein T. Ectomycorrhizal fungi mediate belowground carbon transfer between pines and oaks. THE ISME JOURNAL 2022; 16:1420-1429. [PMID: 35042973 PMCID: PMC9039061 DOI: 10.1038/s41396-022-01193-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/29/2021] [Accepted: 01/06/2022] [Indexed: 02/06/2023]
Abstract
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.
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Affiliation(s)
- Rotem Cahanovitc
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Stav Livne-Luzon
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Roey Angel
- Soil and Water Research Infrastructure and Institute of Soil Biology, Biology Centre CAS, České Budějovice, Czech Republic
| | - Tamir Klein
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel.
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Vera M, Adamčík S, Adamčíková K, Hampe F, Caboň M, Manz C, Ovrebo C, Piepenbring M, Corrales A. Morphological and genetic diversification of Russula floriformis, sp. nov., along the Isthmus of Panama. Mycologia 2021; 113:807-827. [PMID: 34043494 DOI: 10.1080/00275514.2021.1897377] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Species of Russula are ubiquitous members of ectomycorrhizal fungal communities in tropical ecosystems. However, an important part of the total tropical diversity of this genus and its biogeographic patterns is unknown due to the lack of studies on Russula in tropical ecosystems. We combined molecular, morphological, ecological, and biogeographic data to elaborate concepts for two new subspecies of R. floriformis (subsection Substriatinae). Russula floriformis subsp. floriformis and R. floriformis subsp. symphoniae are described as new from montane forest dominated by Quercus and/or Oreomunnea (Fagales) from Colombia and Panama, respectively. Phylogenies were constructed using nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), D1-D2 domains of nuc 28S rDNA (28S), and partial regions of the second largest subunit of RNA polymerase II (rpb2) and translation elongation factor 1-alpha (tef1). Similar environmental conditions, similar morphology, and an ITS sequence similarity higher than 99% with only three different positions indicate that these two subspecies are closely related. Detailed observations of microscopic structures and analyses of further DNA loci, however, revealed morphological and molecular characteristics that allow distinguishing the two subspecies of R. floriformis. Spatial distribution and phylogenetic proximity of the two Russula subspecies and their ectomycorrhizal hosts, i.e., species of Quercus, suggest that their diversification is a result of comigration, adaptation, and geographic isolation along the Isthmus of Panama during the Pliocene and Pleistocene.
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Affiliation(s)
- Michelle Vera
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Slavomír Adamčík
- Institute of Botany, Plant Science and Biodiversity Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 23 Bratislava, Slovakia
| | - Katarína Adamčíková
- Department of Plant Pathology and Mycology, Institute of Forest Ecology, Slovak Academy of Sciences Zvolen, Akademická 2, 949 01 Nitra, Slovakia
| | | | - Miroslav Caboň
- Institute of Botany, Plant Science and Biodiversity Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 23 Bratislava, Slovakia
| | - Cathrin Manz
- Department of Mycology, Goethe University Frankfurt am Main, Biologicum, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany
| | - Clark Ovrebo
- Department of Biology, University of Central Oklahoma, 100 N. University Drive, Edmond, Oklahoma 73034
| | - Meike Piepenbring
- Department of Mycology, Goethe University Frankfurt am Main, Biologicum, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany
| | - Adriana Corrales
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
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Cruz-Paredes C, Frøslev TG, Michelsen A, Bang-Andreasen T, Hansen M, Ingerslev M, Skov S, Wallander H, Kjøller R. Wood ash application in a managed Norway spruce plantation did not affect ectomycorrhizal diversity or N retention capacity. FUNGAL ECOL 2019. [DOI: 10.1016/j.funeco.2018.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Smith ME, Castellano MA, Frank JL. Hymenogaster macmurphyi and Splanchnomyces behrii are sequestrate species of Xerocomellus from the western United States. Mycologia 2018; 110:605-617. [PMID: 29993332 DOI: 10.1080/00275514.2018.1465299] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Hymenogaster is an ectomycorrhizal genus of brown-spored sequestrate fungi that is related to the mushroom-forming genera Hebeloma and Alnicola (Agaricales). However, because of difficulties in morphological taxonomy of sequestrate fungi, Hymenogaster has become a polyphyletic repository for a variety of unrelated brown-spored sequestrate species. During studies of ectomycorrhizal ecology and sequestrate fungal evolution in the western USA, we encountered specimens of a morphologically unique species. It was originally described as Hymenogaster macmurphyi, but our morphological and molecular analyses indicate that it is not closely related to Hymenogaster. Phylogenetic analyses of multiple gene regions indicate that H. macmurphyi is actually a member of the Boletineae (Boletales, Basidiomycota) and is nested within the epigeous genus Xerocomellus, distantly related to any of the other known genera of sequestrate Boletales. While examining additional herbarium collections, we came upon isotype material of Splanchnomyces behrii, which represents a closely related species. Here we document the morphology and phylogenetic affinities of these unusual sequestrate Boletineae and transfer both species to Xerocomellus as X. macmurphyi and X. behrii. During our study, we also noted that the sequestrate taxon Rhopalogaster transversarius is nested within the epigeous genus Suillus.
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Affiliation(s)
- Matthew E Smith
- a Department of Plant Pathology , University of Florida , Gainesville , Florida 32611
| | - Michael A Castellano
- b US Department of Agriculture, Forest Service , Northern Research Station, Forestry Sciences Laboratory , 3200 Jefferson Way, Corvallis , Oregon 97331
| | - Jonathan L Frank
- c Department of Biology , Southern Oregon University , 1250 Siskiyou Boulevard, Ashland , Oregon 97520
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Taxonomy and pathogenicity of Olpidium brassicae and its allied species. Fungal Biol 2018; 122:837-846. [PMID: 30115317 DOI: 10.1016/j.funbio.2018.04.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 04/23/2018] [Accepted: 04/24/2018] [Indexed: 02/05/2023]
Abstract
The classification and physiology of the zoosporic plant-pathogen Olpidium brassicae and its relationships with the closely-related species are often confusing. This review focuses on these species and intends to differentiate them based on the literatures published since the discovery and establishment of the species by Woronin in 1878 under the name of Chytridium brassicae to current molecular era. The goal of this review is to help researchers better understand the taxonomy, the host range, and the potential role in plant health of O. brassicae-related species. To reach the goal, we reviewed the rationales behind the creation or reduction in synonymy of the different names for O. brassicae and its allied species in order to elucidate the evolution of the species concept on them based on the traditional morphological studies. Furthermore, the studies by molecular biology methods improve our knowledge and perspectives on O. brassicae and its host specificity. In particular, we clarify the differences between O. brassicae and Olpidium virulentus, and propose potential new research avenues. We therefore hope that this review will give a better perspective on Olpidium spp. and their potential role in the root microbiome of plants in natural environments and in agricultural settings.
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Kohout P, Tedersoo L. Effect of soil moisture on root-associated fungal communities of Erica dominans in Drakensberg mountains in South Africa. MYCORRHIZA 2017; 27:397-406. [PMID: 28083703 DOI: 10.1007/s00572-017-0760-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/03/2017] [Indexed: 06/06/2023]
Abstract
Ericoid mycorrhiza represents a key adaptation of the Ericaceae plants to facilitate their establishment in harsh conditions. The Ericaceae are a large family of flowering plants, with global distribution. However, our current knowledge about the ericoid mycorrhizal fungal diversity and ecology largely relates to the Northern Hemisphere. Our study focused on the assembly of root-associated fungal (RAF) communities of Erica dominans in two types of microhabitats of contrasting moisture along an elevation gradient in Drakensberg mountains in South Africa. RAF communities were determined by 454-sequencing of the internal transcribed spacer (ITS) region of ribosomal DNA. The majority of RAF showed affinity to the orders Helotiales, Pezizales, and Pleosporales. Microhabitat type as well as elevation had significant but weak effect on RAF community composition. We identified two putative ericoid mycorrhizal fungi, the ecological niches of which were differentiated between the studied microhabitats. Our study also provides one of the first comprehensive data about RAF communities of Ericaceae on African continent and shows the occurrence of the most studied ericoid mycorrhizal fungus Pezoloma ericae (belonging to P. ericae aggregate) in roots of Ericaceae host plant in Africa.
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Affiliation(s)
- Petr Kohout
- Institute of Ecology and Earth Sciences, University of Tartu, 50411, Tartu, Estonia.
- Institute of Botany, Academy of Sciences of the Czech Republic, 252 43, Průhonice, Czech Republic.
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 128 01, Prague 2, Czech Republic.
| | - Leho Tedersoo
- Natural History Museum, University of Tartu, 50411, Tartu, Estonia
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Alvarez-Manjarrez J, Villegas-Ríos M, Garibay-Orijel R, Contreras-Pacheco M, Kõljalg U. Tomentella brunneoincrustata, the first described species of the Pisonieae-associated Neotropical Tomentella clade, and phylogenetic analysis of the genus in Mexico. Mycol Prog 2015. [DOI: 10.1007/s11557-015-1152-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Jakucs E, Erős-Honti Z, Seress D, Kovács GM. Enhancing our understanding of anatomical diversity in Tomentella ectomycorrhizas: characterization of six new morphotypes. MYCORRHIZA 2015; 25:419-429. [PMID: 25564437 DOI: 10.1007/s00572-014-0622-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 12/10/2014] [Indexed: 06/04/2023]
Abstract
Ectomycorrhizas (ECM) formed by Tomentella species (Thelephorales, Basidiomycota) were collected in beech forests of Hungary and studied using anatomical and molecular phylogenetic methods. The mycobionts were identified by analysing the sequences of nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) regions together with sequences obtained from public databases. At the sampling plots, we found the occurrence of 11 Tomentella morphotypes. Among these, six morphotypes (four identified, Tomentella atroarenicolor, Tomentella bryophila, Tomentella lapida, Tomentella subclavigera, and two unidentified) were morpho-anatomically characterized for the first time. Although the six morphotypes differed anatomically from each other and from Tomentella ectomycorrhizas described previously, they shared anatomical features common to tomentelloid ectomycorrhizas fungi. These results expand our understanding of the diversity of this widely distributed ectomycorrhizal genus.
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Affiliation(s)
- Erzsébet Jakucs
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
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De la Varga H, Águeda B, Ágreda T, Martínez-Peña F, Parladé J, Pera J. Seasonal dynamics of Boletus edulis and Lactarius deliciosus extraradical mycelium in pine forests of central Spain. MYCORRHIZA 2013; 23:391-402. [PMID: 23392533 DOI: 10.1007/s00572-013-0481-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 01/24/2013] [Indexed: 06/01/2023]
Abstract
The annual belowground dynamics of extraradical soil mycelium and sporocarp production of two ectomycorrhizal fungi, Boletus edulis and Lactarius deliciosus, have been studied in two different pine forests (Pinar Grande and Pinares Llanos, respectively) in Soria (central Spain). Soil samples (five per plot) were taken monthly (from September 2009 to August 2010 in Pinar Grande and from September 2010 to September 2011 in Pinares Llanos) in eight permanent plots (four for each site). B. edulis and L. deliciosus extraradical soil mycelium was quantified by real-time polymerase chain reaction, with DNA extracted from soil samples, using specific primers and TaqMan® probes. The quantities of B. edulis soil mycelium did not differ significantly between plots, but there was a significant difference over time with a maximum in February (0.1576 mg mycelium/g soil) and a minimum in October (0.0170 mg mycelium/g soil). For L. deliciosus, significant differences were detected between plots and over time. The highest amount of mycelium was found in December (1.84 mg mycelium/g soil) and the minimum in February (0.0332 mg mycelium/g soil). B. edulis mycelium quantities were positively correlated with precipitation of the current month and negatively correlated with the mean temperature of the previous month. Mycelium biomass of L. deliciosus was positively correlated with relative humidity and negatively correlated with mean temperature and radiation. No significant correlation between productivity of the plots with the soil mycelium biomass was observed for any of the two species. No correlations were found between B. edulis sporocarp production and weather parameters. Sporocarp production of L. deliciosus was positively correlated with precipitation and relative humidity and negatively correlated with maximum and minimum temperatures. Both species have similar distribution over time, presenting an annual dynamics characterized by a seasonal variability, with a clear increase on the amounts of biomass during the coldest months of the year. Soil mycelial dynamics of both species are strongly dependent on the weather.
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Affiliation(s)
- Herminia De la Varga
- IRTA, Sustainable Plant Protection, Centre de Cabrils, Ctra. de Cabrils, Km 2, 08348 Cabrils, Barcelona, Spain.
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12
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13
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Berner C, Johansson T, Wallander H. Long-term effect of apatite on ectomycorrhizal growth and community structure. MYCORRHIZA 2012; 22:615-621. [PMID: 22451218 DOI: 10.1007/s00572-012-0438-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/07/2012] [Indexed: 05/31/2023]
Abstract
Ectomycorrhizal (ECM) fungi are efficient at taking up phosphorus (P) from mineral sources, such as apatite, which are not easily available to the host trees. Since ECM fungal species differ in P uptake rates, it can be expected that the composition of the ECM fungal community will change upon exposure to apatite, provided that the P transfer is rewarded by more carbon being transferred to the fungal symbiont. Control and apatite-amended mesh bags were buried in pairs in the humus layer of a P-poor Norway spruce forest. The ECM fungal community that colonized these bags was analyzed by DNA extraction, PCR amplification of the internal transcribed spacer (ITS) region, cloning, and random sequencing. Fungal biomass was estimated by ergosterol analysis. No change in the ECM fungal community structure was seen after 5 years of apatite exposure, although the fungal biomass increased threefold upon apatite amendment. Our results indicate that host trees enhance carbon allocation to ECM fungi colonizing P sources in P-poor forests but the lack of change in the composition of the ECM fungal community suggests that P transfer rates were similar among the species. Alternatively, higher P transfer among certain species was not rewarded with higher carbon transfer from the host.
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Affiliation(s)
- Christoffer Berner
- Microbial Ecology, Department of Biology, Lund University, Lund, Sweden.
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Wang Q, He XH, Guo LD. Ectomycorrhizal fungus communities of Quercus liaotungensis Koidz of different ages in a northern China temperate forest. MYCORRHIZA 2012; 22:461-470. [PMID: 22138969 DOI: 10.1007/s00572-011-0423-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 11/22/2011] [Indexed: 05/31/2023]
Abstract
Ectomycorrhizal (ECM) fungal communities of Quercus liaotungensis of different ages (seedlings, young trees and mature trees) in the growing seasons (June and September) between 2007 and 2009 were studied in a temperate forest of northern China. A total of 66 ECM fungal taxa were identified based on ECM morphotyping, PCR-RFLP, and DNA sequence data. Of these fungal taxa, 51 were Basidiomycetes (77.3%) and 15 were Ascomycetes (22.7%). Cenococcum geophilum was the dominant species. Thelephoraceae (16 taxa), Sebacinaceae (12 taxa) and Russulaceae (seven taxa) were the most species-rich and abundant ECM fungi, accounting for 19.5%, 17.6% and 8.3% of the total ECM root tips, respectively. Results of multiple response permutation procedure (MRPP) analysis indicated that there were marginally significant effects of tree ages (A = 0.01801, P = 0.054) and growing seasons (A = 0.01908, P = 0.064) on the ECM fungal species composition of Q. liaotungensis in a temperate forest.
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Affiliation(s)
- Qin Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
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McCORMICK MELISSAK, LEE TAYLOR D, JUHASZOVA KATARINA, BURNETT ROBERTK, WHIGHAM DENNISF, O’NEILL JOHNP. Limitations on orchid recruitment: not a simple picture. Mol Ecol 2012; 21:1511-23. [DOI: 10.1111/j.1365-294x.2012.05468.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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De la Varga H, Agueda B, Martínez-Peña F, Parladé J, Pera J. Quantification of extraradical soil mycelium and ectomycorrhizas of Boletus edulis in a Scots pine forest with variable sporocarp productivity. MYCORRHIZA 2012; 22:59-68. [PMID: 21494822 DOI: 10.1007/s00572-011-0382-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 04/05/2011] [Indexed: 05/30/2023]
Abstract
The availability of most edible ectomycorrhizal mushrooms depends on their natural fructification. Sporocarp formation of these fungi is linked to habitat characteristics and climate conditions, but these data alone do not explain all the trends of fungal fruiting and dynamics. It could be hypothesized that the amount of soil mycelia could also be related to the production of carpophores. Soil samples (five cylinders of 250 cm(3) per plot) were taken monthly, from September to November, in five fenced permanent plots (5 × 5 m) in Pinar Grande (Soria, Spain), a Pinus sylvestris stand situated in the north of the Sistema Ibérico mountain range. Plots were chosen to establish a gradient of Boletus edulis productivity from 0 to 38.5 kg/ha year, according to the mean fresh weight of sporocarps collected during the last 10 years. B. edulis ectomycorrhizal root tips were identified in each soil sample according to its morphology and counted. DNA extractions were performed with the PowerSoil(TM) DNA Isolation Kit and quantification of extraradical soil mycelium by real-time polymerase chain reaction using specific primers and a TaqMan® probe. The concentration of soil mycelium of B. edulis (mg mycelium/g soil) did not differ significantly between plots (p = 0.1397), and sampling time (p = 0.7643) within the fructification period. The number of mycorrhizal short roots per soil volume showed significant differences between the plots (p = 0.0050) and the three sampling times (p < 0.0001). No significant correlation between the number of mycorrhizas and the productivity of the plot (kg of B. edulis/ha year) was detected (p = 0.615). A statistically significant positive correlation (p = 0.0481) was detected between the concentration of mycelia of B. edulis in the soil samples and the presence of short roots mycorrhizal with B. edulis in these samples. The productivity of the plots, in terms of sporocarps produced during the last 10 years, was not correlated either with the concentration of soil mycelium or with the presence or abundance of ectomycorrhizas.
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Douhan GW, Vincenot L, Gryta H, Selosse MA. Population genetics of ectomycorrhizal fungi: from current knowledge to emerging directions. Fungal Biol 2011; 115:569-97. [PMID: 21724164 DOI: 10.1016/j.funbio.2011.03.005] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 03/06/2011] [Accepted: 03/12/2011] [Indexed: 11/25/2022]
Abstract
Ectomycorrhizal (EM) fungi are major microbial components of boreal, temperate and Mediterranean forests, as well as some tropical forest ecosystems. Nearly two decades of studies have clarified many aspects of their population biology, based on several model species from diverse lineages of fungi where the EM symbiosis evolved, i.e. among Hymenomycetes and, to a lesser extent, among Ascomycetes. In this review, we show how tools for individual recognition have changed, shifting from the use of somatic incompatibility reactions to dominant and non-specific markers (such as random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP)) and, more recently, to co-dominant and specific markers (such as microsatellites and single nucleotide polymorphisms (SNPs)). At the same time, the theoretical focus has also changed. In earlier studies, a major aim was the description of genet size and popul/ation strategy. For example, we show how some studies supported or challenged the simple, classical model of colonization of new forest stands by ruderal (R) species, propagating by spores and forming small genets, progressively replaced in older forests by more competitive (C) species, propagating by mycelial growth and forming larger genets. By contrast, more recent studies give insights into some genetic traits, such as partners' assortment (allo- versus autogamy), genetic structure of populations and gene flow that turn out to depend both on distance and on whether spores are animal- or wind-dispersed. We discuss the rising awareness that (i) many morphospecies contain cryptic biological species (often sympatric) and (ii) trans- and inter-continental species may often contain several biological species isolated by distance. Finally, we show the emergence of biogeographic approaches and call for some aspects to be developed, such as fine-scale and long-term population monitoring, analyses of subterranean populations of extra-radical mycelia, or more model species from the tropics, as well as from the Ascomycetes (whose genetic idiosyncrasies are discussed). With the rise of the '-omics' sciences, analysis of population structure for non-neutral genes is expected to develop, and forest management and conservation biology will probably profit from published and expected work.
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Affiliation(s)
- Greg W Douhan
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA 92521, USA.
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