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Ectomycorrhizal fungal communities in high mountain conifer forests in central Mexico and their potential use in the assisted migration of Abies religiosa

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Abies religiosa forests in central Mexico are the only overwinter refuge of the monarch butterfly and provide important ecosystem services. These forests have lost 55% of their original area and as a consequence, diversity and biotic interactions in these ecosystems are in risk. The aim of this study was to compare the soil fungal diversity and community structure in the Abies religiosa forests and surrounding Pinus montezumae, Pinus hartwegii, and coniferous mixed forest plant communities to provide data on ecology of mycorrhizal interactions for the assisted migration of A. religiosa. We sampled soil from five coniferous forests, extracted total soil DNA, and sequenced the ITS2 region by Illumina MiSeq. The soil fungi community was integrated by 1746 taxa with a species turnover ranging from 0.280 to 0.461 between sampling sites. In the whole community, the more abundant and frequent species were Russula sp. (aff. olivobrunnea), Mortierella sp.1, and Piloderma sp. (aff. olivacearum). The ectomycorrhizal fungi were the more frequent and abundant functional group. A total of 298 species (84 ectomycorrhizal) was shared in the five conifer forests; these widely distributed species were dominated by Russulaceae and Clavulinaceae. The fungal community composition was significantly influenced by altitude and the lowest species turnover happened between the two A. religiosa forests even though they have different soil types. As Pinus montezumae forests have a higher altitudinal distribution adjacent to A. religiosa and share the largest number of ectomycorrhizal fungi with it, we suggest these forests as a potential habitat for new A. religiosa populations.
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Ectomycorrhizal fungal communities in high mountain conifer forests
in central Mexico and their potential use in the assisted migration
of Abies religiosa
Andrés Argüelles-Moyao
&Roberto Garibay-Orijel
Received: 13 December 2017 /Accepted: 29 May 2018 /Published online: 11 June 2018
#Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abies religiosa forests in central Mexico are the only overwinter refuge of the monarch butterfly and provide important
ecosystem services. These forests have lost 55% of their original area and as a consequence, diversity and biotic
interactions in these ecosystems are in risk. The aim of this study was to compare the soil fungal diversity and
community structure in the Abies religiosa forests and surrounding Pinus montezumae,Pinus hartwegii,andconiferous
mixed forest plant communities to provide data on ecology of mycorrhizal interactions for the assisted migration of A.
religiosa. We sampled soil from five coniferous forests, extracted total soil DNA, and sequenced the ITS2 region by
Illumina MiSeq. The soil fungi community was integrated by 1746 taxa with a species turnover ranging from 0.280 to
0.461 between sampling sites. In the whole community, the more abundant and frequent species were Russula sp. (aff.
olivobrunnea), Mortierella sp.1, and Piloderma sp. (aff. olivacearum). The ectomycorrhizal fungi were the more fre-
quent and abundant functional group. A total of 298 species (84 ectomycorrhizal) was shared in the five conifer forests;
these widely distributed species were dominated by Russulaceae and Clavulinaceae. The fungal community composition
was significantly influenced by altitude and the lowest species turnover happened between the two A. religiosa forests
even though they have different soil types. As Pinus montezumae forests have a higher altitudinal distribution adjacent
to A. religiosa and share the largest number of ectomycorrhizal fungi with it, we suggest these forests as a potential
habitat for new A. religiosa populations.
Keywords Fungal ecology .Beta diversity .Functional groups .Environmental decision-making .Monarch butterfly habitat
The high species extinction rate in the Anthropocene (Pievani
2014) is driving to a dramatic loss of lineages constraining the
functionality of ecosystems and reducing our ability to adapt
to a changing environment. In Mexico, the area of primary
temperate forest has been reduced substantially over the pre-
vious 20 years. This has been particularly severe for Pinus and
Quercus species (Miranda-Aragón et al. 2012) and for Abies
religiosa (Ramirez et al. 2015). High altitude conifer forests
are among the most imperiled ecosystems in the Trans-
Mexican Volcanic Belt in central Mexico due to climate
change and deforestation. Temperate forests in these moun-
tains are characterized by an alpine monodominant Pinus
hartwegii forest at elevations above 3500 m, followed by
Pinus montezumae from 3000 to 3500 m and A. religiosa from
2800 to 3000 m.
Electronic supplementary material The online version of this article
( contains supplementary
material, which is available to authorized users.
*Roberto Garibay-Orijel
Andrés Argüelles-Moyao
Laboratorio de Sistemática, Ecología y Aprovechamiento de Hongos
Ectomicorrízicos, Departamento de Botánica, Instituto de Biología,
Universidad Nacional Autónoma de México, Circuito Exterior s/n,
Ciudad Universitaria. Del. Coyoacán, C.P. 04510 Mexico
City, CDMX, Mexico
Posgrado en Ciencias Biológicas, Edificio B, 1° Piso, Unidad de
Posgrado, Circuito de Posgrados, Universidad Nacional Autónoma
de México, Ciudad Universitaria, Del. Coyoacán, C.P. 04510 Mexico
City, CDMX, Mexico
Mycorrhiza (2018) 28:509521
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... This forest has a diverse understory while the overstory is dominated by Abies religiosa. Nonetheless, other ectomycorrhizal hosts are also present but in very low abundance, such as Alnus jorullensis, Salix paradoxa, Comarostaphyllis discolor, Quercus laurifolia (scarce), and Arbutus xalapensis (Argüelles-Moyao et al., 2017;Argüelles-Moyao and Garibay-Orijel, 2018). ...
Abies religiosa's forests are severely endangered as a result of climate change; to save this species and its biological interactions, population assisted migration is discussed in forest management, but not in the microbial ecology field. Our objectives were to analyze its mycorrhizal networks; and, with this data, to identify potential facilitator plants and it's most important mycorrhizal fungal links. This information could be used together in assisted migration programs to connect Abies religiosa saplings to their mycorrhizal network and improve their field establishment. We collected 47 rhizosphere samples from 19 plant species and sequenced their fungal ITS2 region by Illumina. In the whole fungal community, 464 species were mycorrhizal fungi with assigned guild (32%). In this subset, 85 fungi are arbuscular, 365 ectomycorrhizal and 14 from orchid-mycorriza. The Abies religiosa bipartite network is low nested and highly modular, and has a scale-free architecture. Besides Abies religiosa, the plants with the largest degree and the lowest average shortest path were Salix paradoxa, Muhlenbergia spp., and Baccharis conferta. The most important fungal nodes are species of Cortinarius, Genea, Rhodoscypha, Russula, and Tomentella. We suggest to evaluate the Abies' future establishment in the following scheme: in the first year reintroduce Muhlenbergia spp., and Baccharis conferta, in the second year Salix paradoxa, and in the third year–once the mycorrhizal network is reestablished– Abies religiosa' saplings in close proximity of these plants. This scheme is proposed using the data and network analyses of the present study. Authorized share link:,XbFFXEDn
... The genus typically associates with arbuscular mycorrhizal (AM) fungi (Soudzilovskaia et al., 2020) although some studies have reported individuals forming ECM associations (Reinsvold and Reeves, 1986;Dean et al., 2015). Juniperus species have been largely re-introduced for reforesting pine-oak forests of Central Mexico that are naturally dominated by ECM associations (García-Guzmán et al., 2017;Argüelles-Moyao and Garibay-Orijel, 2018). Co-occurring AM and ECM plants are likely to spontaneously share mycorrhizal fungi in their native range (Kadowaki et al., 2018;Toju and Sato, 2018), but these aspects have scarcely been addressed for reforestation purposes. ...
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Competition for resources between arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) plants can alter belowground mycorrhizal communities, but few studies have investigated host effects on both AM and ECM communities. In Central Mexico, the AM plant Juniperus deppeana is frequently used for reforesting areas affected by soil erosion, while the surrounding native forests are dominated by ECM oak trees. Oaks are capable of associating with both AM and ECM fungi during part of their life cycle (a feature known as dual mycorrhization) but it is unclear whether junipers possess such ability. To assess how juniper planting may affect belowground fungal interactions with oaks, we investigated mycorrhizal associations in J. deppeana and Quercus rugosa seedlings along a disturbance gradient: a native oak forest, a mixed Juniperus-Quercus population in secondary vegetation and a juniper site severely degraded by mining extraction. We measured root colonization and identified fungal communities using soil and root meta-barcoding of the ITS2 rDNA region. ECM fungal community composition was strongly affected by disturbance (regardless of host), while the community composition of AM fungi was mostly host-dependent, with a higher AM fungal richness in J. deppeana . Importantly, the fungal communities associated with Q. rugosa seedlings significantly changed in the vicinity of juniper trees, while those of J. deppeana seedlings were not affected by the presence of oak trees. Even though ECM fungal richness was higher in Q. rugosa and in the native forest, we detected a variety of ECM fungi associated exclusively with J. deppeana seedlings, suggesting that this plant species may be colonized by ECM fungi. Our results indicate that J. deppeana can alter ECM native fungal communities, with implications for its use in reforestation of mixed oak forests.
... To date Faxon fir has not been investigated for its reliance on mycorrhizal symbioses in environmental adaptation and stress tolerance, though some recent studies suggested that the responses of Faxon fir to warming might involve alteration of nutrient uptakes by ECM roots (Pu et al., 2017;Lu et al., 2017). In Abies firma, it was found that ECM morphology identification and DNA sequence greatly varied under different environmental gradients (Matsuda and Hijii,1999a, 1999b, 2004; whereas the study of Argüelles-Moyao and Garibay-Orijel (2018) showes that ECM symbioses determine the habitat range of Abies religiosa in high elevational distribution. ...
Faxon fir (Abies fargesii var. faxoniana) is endemic to the cool and moist subalpine region of Southwest China, where the occurrence of warmer and drier climate may impose uncertain environmental constraints to its population stability and community scuccession. Here we determine the role of root-mycorrhizal symbiosis in the adaptability of Faxon fir to varying environmental conditions. The traits and foraging behaviors of the ectomycorrhizal (ECM) associations in Faxon fir were investigated along elevational gradient in three representative natural distributional areas of the species. Soil and Faxon fir root samples were collected from varying elevations in three study areas, namely Wolong Nature Reserve, Miyaluo Nature Reserve, and Wanglang Nature Reserve, in Sichuan province, Southwest China, using point-centered quarter sampling method, with 32 samples for each elevational site. Measurements were made on fine root biomass, ECM morphological diversity and soil exploration types, density and superficial area of ECM root tips, and soil chemistry. Values for selective climatic variables were derived from the national grid-datasets of meteorology of China. Principle component analysis (PCA), redundancy analysis (RDA) and linear regressions were performed to determine the inter-relationships of ECM root traits with climatic and soil factors, and the variations of the ECM root traits with elevation. We found that the biomass of absorptive fine roots and ECM morphological diversity decreased with rising elevations and increasing soil water content or precipitation and soil C:N ratio. The foraging ability of ECM roots, inferred by the soil exploration type of ECM symbionts, and density and superficial area of ECM root tips, were weakened by warming and drying. Under conditions of low N availability, both the frequency of contact exploration type and ECM root tip density prevailed, whilst the frequency of both short-distance and medium-distance exploration types tended to decline, suggesting conservative carbon cost of ECM root systems in low fertility soil. Overall, our findings suggest that the ECM symbionts in Faxon fir adopt the strategy of C investment in root systems in response to warming and drying while relying on the functional efficiency of the ECM root tips toward the colder and more humid environments, and that Faxon fir may sustain moderate changes in the regional climate and maintain population stability, partially owning to adjustment of the ECM foraging strategies.
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Changes in soil fungal community caused by land use have not been sufficiently studied in South-American Andosols, considered globally as important food production areas. This study analyzed 26 soil samples of Andosols collected from locations devoted to conservation, agriculture and mining activities in the southeastern region of Antioquia, Colombia, to establish differences between fungal communities as indicators of the degree of soil perturbation. The study developed a novel heminested PCR with primers SSUmCf Mix, ITS4 and fITS7 to assess Arbuscular Mycorrhizal Fungi detection in a Illumina MiSeq metabarcoding on nuclear ribosomal ITS2 region. A non-metric multidimensional scaling allowed exploring driver factors of fungal community changes, while fitted Dirichlet-multinomial models and PERMANOVA tests allowed identifying the correlations between alpha diversity indexes and community dissimilarities, as well as the significance of land use effects on fungal community composition. Furthermore, response ratios were determined to assess effect size by land use over relevant taxa. Results suggest a good coverage of fungal diversity with a detection of 10,529 high-quality ITS2 sequences belonged to phylum Glomeromycota. The analysis shows strong correlations of Shannon and Fisher indexes with dissimilarities on fungal communities among land uses (r=0.94), related to variations in temperature, air humidity and organic matter contents that lead to significant responses in abundances of relevant orders (such as Wallemiales and Trichosporonales). The study highlights the rich fungal biodiversity of the tropical Andosols, their specific sensitivities to environmental perturbation factors, and the useful range of a metabarcoding approach to characterize soil fungal communities.
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Abies pindrow (Royle ex D.Don) Royle (Himalayan pindrow fir) is an imperative conifer native to Kashmir Himalaya, where its mono-dominant forests provide vital ecosystem services, besides being dwelling to endangered flora and fauna. However, in the past few decades, these forests have relentlessly undergone unprecedented deforestation and degradation, and consequently, biodiversity and biotic interactions are jeopardized in these ecosystems. Ectomycorrhizal (ECM) fungi of this fir species may prove helpful in the successful restoration of structural organization and functional integrity of these degraded fir forests. Consequently, the present study was undertaken to explore and document the root-associated ectomycorrhizal symbionts of Himalayan pindrow fir through ectomycorrhizal root tip surveys for morphotyping together with Next Generation Sequencing (Illumina MiSeq) of ITS region of fungal nuclear ribosomal DNA. Fine ECM infected root tips were grouped into fourteen distinct morphotypes based on the morphological attributes, with the monopodial pyramidal type being the most abundant morphotype. The molecular characterization revealed high fungal diversity associated with the roots of Himalayan pindrow fir. A total of 2,51,158 reads were obtained, representing 136 OTUs, of which 62 have confirmed ectomycorrhizal status. In addition, fir roots were found to host a large suite of diverse fungal taxa, including saprotrophs, parasites, and pathogens. FUNGuild assigned 9 prominent guilds to the fungi associated with the fir roots, and ectomycorrhizal fungi represented the largest guild. OTUs belonging to division Basidiomycota were more abundant than those belonging to Ascomycota. Inocybe, Russula, Otidea, Sebacina, Chalara, Tomentella, Cenococcum and Wilcoxina were the abundant ECM forming genera. The results of this study can serve as baseline information for future research and pave the way for experimental evaluation of these ectomycorrhizal mutualists for their prospective use in ectomycorrhization and ECM-mediated forest restoration.
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Key message A systematic review from 1962 to August 2021 summarizes the research on Hartwegʼs pine (Pinus hartwegii). We identify research gaps and propose new direction for future studies and discuss the main study topics. Abstract Hartwegʼs pine (Pinus hartwegii Lindl.) is a high-value timber species adapted to the harsh alpine environment of high-elevation mountains (3000–4200 m) in Mexico, where it provides a wide array of ecosystem services to society. However, this species is currently facing temperature increases associated with global warming, with models predicting upward altitudinal shifts to maintain suitable growth conditions. Here, we present a systematic review of Hartwegʼs pine to establish current knowledge, identify research gaps, and indicate directions for future studies. This search recovered 196 scientific references from 1962 to August 2021, which were classified into 21 research topics. References to Hartwegʼs pine increased considerably during the period from 2000 to 2021, representing 77% of the total publications. Most of the references were focused on the management of the species (n = 89) and its relationships with climate change (n = 49). Fewer references were focused on human impacts on the species, taxonomy, and systematics, as well as biogeochemical and hydrological cycles, phenology, and evolution. Most of the study areas were in the Trans-Mexican Volcanic Belt, such as in Izta-Popo National Park, Cofre de Perote National Park, the Nevado de Toluca Flora and Fauna Protection Area, and Cumbres del Ajusco National Park. These results highlight the incipient knowledge that we have about population genetics, phenotypic plasticity, physiology, biotic interactions and about of the specific environmental conditions where P. hartwegii populations develop, which limits our capacity to understand how this species will respond to global warming and whether there are risks to the persistence of these forests and the ecosystem services they provide, both to local human populations and those located farther down the mountain.
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Pachyphlodes is a lineage of ectomycorrhizal, hypogeous, sequestrate ascomycete fungi native to temperate and subtropical forests in the Northern Hemisphere. Pachyphlodes species form ectomycorrhizae mainly with Fagales hosts. Here we describe two new species of Pachyphlodes , P. brunnea , and P. coalescens , based on morphological and phylogenetic analysis. Pachyphlodes brunnea is distributed in the states of Tamaulipas and Nuevo León in northern México, occurring with Quercus and Juglans species. It is characterized by its dark brown peridium, white gleba, and spores with capitate columns. Pachyphlodes coalescens is distributed in the states of Michoacán and Tlaxcala in central and southwestern México co-occurring with Quercus and is distinguished by its reddish-brown peridium, light yellow gleba, and spore ornamentation. Both species, along with P. marronina , constitute the Marronina clade. This clade contains North American species characterized by a brown peridium and spores ornamented with capitate spines to coalesced spine tips that form a partial perispore.
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Aim Estimating genetic diversity is key for understanging biogeographic and evolutionary processes. However, gathering genetic information is not feasible for all taxa or populations, particularly in the tropical regions. Identifying proxies for inferring such values has thus become essential. Here, we built on the niche centrality hypothesis (NCH; or central‐abundance hypothesis) and the nearly neutral theory of evolution (NNT) to identify some of such proxies using a montane tropical conifer species‐pair as model. The NCH predicts more genetic diversity under optimal ecological conditions, which should also allow for more efficient purifying selection, according to the NNT. Location The Transmexican Volcanic Belt, central Mexico. Taxa A fir species‐pair endemic to central Mexico, Abies flinckii and A. religiosa. Methods We estimated patterns of genetic diversity from nuclear SSRs (A, HE), and gene‐coding sequences (πS, πN), together with the efficacy of purifying selection, measured as πN/πS. After testing for niche overlap, we used several geographic and ecological proxies (i.e. longitude, latitude, elevation, estimated area and distance to the niche centroid in the present and in the LGM) to predict genetic diversity and πN/πS using general linear models. Results Populations at the west of the Trans Mexican Volcanic Belt (TVB) had lower genetic diversity than populations in the east of this mountain chain. Both species had significant niche overlap. The principal predictors for neutral genetic diversity (HE, A and πS) were longitude and latitude, followed by the current distance to the niche centroid; the efficiency of purifying selection was mostly accounted for by the current distance to the niche centroid (which was also correlated with elevation). No correlation was observed between genetic diversity or πN/πS and current population area. Main conclusions Historical and ecological factors have to be taken into account for explaining the amounts of genetic diversity in mountain tropical species. Following the NTT, populations closer to the niche centroid are more efficient at eliminating slightly deleterious mutations than marginal stands, independently of their size or geographic location (longitude). Expanding the central‐abundance theory within the scope of the NTT might help reconciling conflicting views concerning the extent of its empirical support.
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In the forests of Ixtlán de Juarez, Oaxaca, the genus Laccaria is one of the most productive at basidiomata level. In this work, we compared the placement of Laccaria in the edible ectomycorrhizal fungi community measured by basidiomata abundance versus mycorrhizae. The sampling took place in 3 sites with Pinus patula dominance. The fungi basidiomata were collected to determine their taxonomic identity and production data (quantity and weight). Mycorrhizae were obtained from soil core samples, which ITS DNA was sequenced for molecular identification. There was no correspondence between the species with higher basidiomata production (L. laccata AR = 0.43, Cantharellus tubaeformis AR = 0.27, Lactarius chrysorrehus AR = 0.10, and L. vinaceobrunnea AR = 0.08) and those with more abundant mycorrhizae (Lactarius aff deceptivus AR = 0.25, Cortinarius aff ochrophyllus AR = 0.12, Hydnum aff cuspidatum AR = 0.05, Russula sp.1 AR = 0.05, and Sebacina aff dimitica AR = 0.05). Potentially, the genera with most basidiomata and mycorrhizae should be used in mycorrhization programs and tested in greenhouse experiments. This would allow the production of ectomycorrhizal inoculums consortia based on most ecologically outstanding species.
Assisted migration is a strategy with potential to improve the adaptation of flora to climate change. The principle types of assisted migration are outlined in this chapter, with examples of each and a discussion of the relevant abiotic and biotic soil factors and risks that have an impact on the successful translocation of plants. Edaphic factors such as pH, soil moisture, depth, etc. play a role in successful establishment and growth of migrated provenances. Biotic factors such as the relationship of ectomycorrhizal fungi with host plants are also important, especially as translocation distances increase. Pathogens in the soil environment can be a constraining factor and a risk to translocation efforts. Landscape-level research, cataloging of relevant provenance trials, and trials providing relevant information for assisted migration in restoration areas are all needed for future progress in managing assisted migration efforts
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Conservation of Abies religiosa (sacred fir) within the Monarch Butterfly Biosphere Reserve (MBBR) in Mexico requires adapti­ve management to cope with expected climatic change, in order to have healthy trees for Danaus plexippus overwintering sites in the future. Open pollinated seeds from fifteen A. religio­sa populations were collected along an elevational gradient (2850-3550 masl; one sampled population every 50 m of eleva­tional difference). Seedlings were evaluated in a common gar­den test over a period of 30 months. We found significant diffe­rences (P < 0.03) among populations in total elongation, final height, date of growth cessation, foliage, stem and total dry weight, as well as frost damage. These differences were stron­gly associated with the Mean Temperature of the Coldest Month (MTCM; r
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The effects of global climate change have highlighted forest ecosystems as a key element in reducing the amount of atmospheric carbon through photosynthesis. The objective of this study was to estimate the amount of carbon content and its percentage capture in a protected Abies religiosa forest in which the study area was zoned with satellite image analysis. Dendrometric and epidometric variables were used to determine the volume and increase of aerial biomass, and stored carbon and its capture rate using equations. The results indicate that this forest contains an average of 105.72 MgC ha−1, with an estimated sequestration rate of 1.03 MgC ha−1 yr−1. The results show that carbon capture increasing depends on the increase in volume. Therefore, in order to achieve the maximum yield in a forest, it is necessary to implement sustainable forest management that favors the sustained use of soil productivity.
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Whether niche processes, like environmental filtering, or neutral processes, like dispersal limitation, are the primary forces driving community assembly is a central question in ecology. Here, we use a natural experimental system of isolated tree “islands” to test whether environment or geography primarily structures fungal community composition at fine spatial scales. This system consists of isolated pairs of two distantly-related, congeneric pine trees established at varying distances from each other and the forest edge, allowing us to disentangle the effects of geographic distance versus host and edaphic environment on associated fungal communities. We identified fungal community composition with Illumina sequencing of ITS amplicons, measured all relevant environmental parameters for each tree - including tree age, size, and soil chemistry - and calculated geographic distances from each tree to all others and to the nearest forest edge. We applied generalized dissimilarity modeling to test whether total and ectomycorrhizal fungal (EMF) communities were primarily structured by geographic or environmental filtering. Our results provide strong evidence that, as in many other organisms, niche and neutral processes both contribute significantly to turnover in community composition in fungi, but environmental filtering plays the dominant role in structuring both free-living and symbiotic fungal communities at fine spatial scales. In our study system, we found pH and organic matter primarily drive environmental filtering in total soil fungal communities and that pH and cation exchange capacity – and, surprisingly, not host species - were the largest factors affecting EMF community composition. These findings support an emerging paradigm that pH may play a central role in the assembly of all soil mediated systems. This article is protected by copyright. All rights reserved.
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DNA metabarcoding is promising for cost-effective biodiversity monitoring, but reliable diversity estimates are difficult to achieve and validate. Here we present and validate a method, called LULU, for removing erroneous molecular operational taxonomic units (OTUs) from community data derived by high-throughput sequencing of amplified marker genes. LULU identifies errors by combining sequence similarity and co-occurrence patterns. To validate the LULU method, we use a unique data set of high quality survey data of vascular plants paired with plant ITS2 metabarcoding data of DNA extracted from soil from 130 sites in Denmark spanning major environmental gradients. OTU tables are produced with several different OTU definition algorithms and subsequently curated with LULU, and validated against field survey data. LULU curation consistently improves α-diversity estimates and other biodiversity metrics, and does not require a sequence reference database; thus, it represents a promising method for reliable biodiversity estimation.
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Ectomycorrhizal (ECM) and ectendomycorrhizal fungal species associated with Pinus montezumae were recorded in 8 year-old trees established in microcosms and compared with those associated with 2 year-old trees, in order to determine their persistence over the long-term. Mycorrhizal root tips were morphologically and anatomically characterized and sequenced. The extension of extramatrical mycelium of ECM fungi with long exploration strategies was evaluated. In total, 11 mycorrhizal species were registered. Seven mycorrhizal species were detected on both 2 and 8 year-old pines: Atheliaceae sp., Rhizopogon aff. fallax, R. aff. occidentalis, Suillus pseudobrevipes, Tuber separans, Wilcoxina mikolae and Wilcoxina rehmii. One species, Thelephora terrestris, was exclusively associated with two year–old seedlings, while Cenococcum geophilum, Pezizaceae sp. and Pyrenomataceae sp. were exclusively found on 8 year-old trees. Atheliaceae sp. was the ECM fungal species that presented the most abundant mycelium. Finally, we report one new fungal species of Pezizaceae occurring as a symbiont of P. montezumae.
Full-text available Few studies have focused on analyzing the effect of native inoculated ectomycorrhizal (ECM) fungal strains on seedlings under field conditions in temperate forests. However, it is crucial to verify that the positive effects of ECM under nursery conditions also occur in the field, favoring their performance. We evaluated the short-term effect of ECMonthree-year-old seedlings of Pinus hartwegii and Abies religiosa in central Mexico by subjecting them to four treatments: inoculation with Inocybe splendens, inoculation with Suillus brevipes (both native strains), inoculation with forest soil, and non-inoculated plants. Percentage of ECM colonization, plant growth (shoot height and stem diameter),and physiological (osmotic potential, stomatal conductance, CO2 assimilation and wáter use efficiency) responses were evaluated. We found that these two ECM species were partial (P. hartwegii) or totally (A. religiosa) replaced after one and a half years in the field. P. hartwegii seedlings increased their water use efficiency during the dry season, but in A. religiosa seedlings, a clear strategy for avoiding water stress was not detected. This ECM replacement had a negative effect on the physiological performance of A. religiosa. Our results emphasize the importance of selecting compatible fungal-host species combinations for nursery inoculation and of using sources of inoculum adapted to the environmental conditions of the transplant site, ensuring root colonization prior to field transplanting to minimize seedling mortality due to wáter stress.
Ectomycorrhizal (EcM) plants have evolved multiple times from arbuscular mycorrhizal or non-mycorrhizal ancestors, and they have a broad distribution on Earth, with abundant recent human introductions. The evolution as well as historical and current distribution of these EcM plant groups and mechanisms of their invasion have remained poorly understood. The purpose of this review/synthesis is fivefold: (1) to determine the time and place of evolution for EcM plant groups based on dated phylogenies and fossil evidence, (2) to characterise the historical and current natural distribution patterns based on fossil record and information from accumulated observations and specimens, (3) to establish the major global biodiversity hotspots for EcM plants based on the present distribution patterns of EcM plant lineages, (4) to determine the relative importance and role of EcM plants in human-mediated plant invasions and to shed light on the mechanisms and (5) integrate this information with climate change scenarios into predictions of the future biogeography of EcM plants.