Search

Biological invasions have historically been addressed mostly from an aboveground perspective, so little is known about the impacts of belowground invasions. We studied the impact of belowground invasions on growth of native tree species and test the possibility of novel interactions between native and non-native hosts and native and non-native belowground symbionts. We combined field and growth chamber studies. With a growth chamber bioassay we compared growth and root colonization percentage of native Nothofagus and non-native invasive pine species, both highly dependent on ectomycorrhizal fungi (EMF), growing in pine invaded and non-invaded soils from native Nothofagus forest. We evaluated the identity of EMF species associated with both hosts in the different soil sources from the bioassay and we performed an in situ root sampling in the field. We found that both hosts grew equally well in both soil sources in terms of biomass, with high percent of root colonization, and no cross-host colonization of symbiotic EMF except for one species of Sistotrema found on both hosts. Soil where invasive hosts are absent is already conditioned by the presence of non-native invasive EMF. Native trees may be able to remain in the invaded area due to the presence of native EMF. The presence of native hosts is not hindering the invasion of non-native hosts and the presence of native belowground fungal mutualists seems not to hinder the spread of their non-native counterparts.

Temperate and boreal forests are increasingly suffering from anthropic degradation. Ectomycorrhizal fungi (EMF) are symbionts with most temperate and boreal forest trees, providing their hosts with soil nutrients and water in exchange for plant carbon. This group of fungi is involved in woody plants’ survival and growth and helps plants tolerate harsh environmental conditions. Here, we describe the current understanding of how EMF can benefit temperate and boreal forest restoration projects. We review current evidence on promising restoration plans that actively use EMF in sites contaminated with heavy metals, affected by soil erosion, and degraded due to clearcut logging and wildfire. We discuss the potential role of this group of fungi for restoring sites invaded by non-native plant species. Additionally, we explore limitations, knowledge gaps, and possible undesired outcomes of the use of EMF in forest restoration, and we suggest how to further incorporate this fungal group into forest management. We conclude that considering EMF – host interactions could improve the chances of success of future restoration programs in boreal and temperate forests.

The American chestnut (Castanea dentata) was once an integral part of eastern United States deciduous forests, with many environmental, economic, and social values. This ended with the introduction of an invasive fungal pathogen that wiped out over three billion trees. Transgenic American chestnuts expressing a gene for oxalate oxidase successfully tolerate infections by this blight fungus, but potential non-target environmental effects should be evaluated before new restoration material is released. Two greenhouse bioassays evaluated belowground interactions between transgenic American chestnuts and neighboring organisms found in their native ecosystems. Potential allelopathy was tested by germinating several types of seeds, all native to American chestnut habitats, in the presence of chestnut leaf litter. Germination was not significantly different in terms of number of seeds germinated or total biomass of germinated seedlings in transgenic and non-transgenic leaf litter. Separately, ectomycorrhizal associations were observed on transgenic and non-transgenic American chestnut roots using field soil inoculum. Root tip colonization was consistently high (>90% colonization) on all plants and not significantly different between any tree types. These observations on mycorrhizal fungi complement previous studies performed on older transgenic lines which expressed oxalate oxidase at lower levels. Along with other environmental impact comparisons, these conclusions provide further evidence that transgenic American chestnuts are not functionally different with regard to ecosystem interactions than non-transgenic American chestnuts.

An undescribed species of Laccaria was discovered in the Santuario del Bosque de Niebla of Xalapa, Mexico, in a montane cloud forest preserved under the protection of the Instituto de Ecologia A.C. in Veracruz State. This new species is distinct based on basidiome morphology and supported by phylogenetic analyses of sequences of the internal transcribed spacer (ITS) and nuclear large subunit (nLSU) of the ribosomal RNA gene. Thirteen different collections obtained during 2012–2014, provided documentation of the broad morphological variation and confirmed the diagnostic color changes of this species. It is phylogenetically associated with Metasection Amethystina but lacks violet pigments in the mycelium and stipe base that are characteristic for species placed in that Metasection. Its relationship to other taxa in Laccaria is not obvious at this time. Descriptions, color images of the basidiomata, scanning electron photomicrographs of basidiospores and comparisons with similar taxa are presented.

Small mammals are generally known to consume and disperse subterranean (hypogeous) fungi, but accounts for this behavior are lacking for the northeastern US. We report on the use of these fungi by a sample of small mammals from the central Adirondack Mountains of New York. We analyzed 57 fecal samples from Peromyscus maniculatus (Deer Mouse), Myodes gapperi (Southern Red-backed Vole), Tamias striatus (Eastern Chipmunk), and Blarina brevicauda (Short-tailed Shrew) to determine whether they were consuming fungi in the central Adirondack Mountains. We found that fecal samples from Eastern Chipmunk (n = 12), Southern Red-backed Vole (n = 14), Short-tailed Shrew (n = 14), and Deer Mouse (n = 17) contained Glomus spp. (arbuscular mycorrhizal fungi) spores (33.3%, 35.7%, 21.4%, and 17.6% of samples, respectively) and Russulaceae spores (66.6%, 35.7%, 7.14% and 5.9% of samples, respectively). One sample from an Eastern Chipmunk also contained Gautieria spores.

Summary Coinvasive ectomycorrhizal (ECM) fungi allow Pinaceae species to invade regions otherwise lacking compatible symbionts, but ECM fungal communities permitting Pinaceae invasions are poorly understood. In the context of Pinaceae invasions on Isla Victoria, Nahuel Huapi National Park, Argentina, we asked: what ECM fungi are coinvading with Pinaceae hosts on Isla Victoria; are some ECM fungal species or genera more prone to invade than others; and are all ECM fungal species that associate with Northern Hemisphere hosts also nonnative, or are some native fungi compatible with nonnative plants? We sampled ECMs from 226 Pinaceae host plant individuals, both planted individuals and recruits, growing inside and invading from plantations. We used molecular techniques to examine ECM fungal communities associating with these trees. A distinctive subset of the ECM fungal community predominated far from plantations, indicating differences between highly invasive and less invasive ECM fungi. Some fungal invaders reported here have been detected in other locations around the world, suggesting strong invasion potential. Fungi that were frequently detected far from plantations are often found in early-successional sites in the native range, while fungi identified as late-successional species in the native range are rarely found far from plantations, suggesting a means for predicting potential fungal coinvaders.

American chestnut (Castanea dentata[Marsh.] Borkh.) dominated the eastern forests of North America, serving as a keystone species both ecologically and economically until the introduction of the chestnut blight,Cryphonectria parasitica, functionally eradicated the species. Restoration efforts include genetic transformation utilizing genes such as oxalate oxidase to produce potentially blight-resistant chestnut trees that could be released back into the native range. However, before such a release can be undertaken, it is necessary to assess nontarget impacts. Since oxalate oxidase is meant to combat a fungal pathogen, we are particularly interested in potential impacts of this transgene on beneficial fungi. This study compares ectomycorrhizal fungal colonization on a transgenic American chestnut clone expressing enhanced blight resistance to a wild-type American chestnut, a conventionally bred American-Chinese hybrid chestnut, and other Fagaceae species. A greenhouse bioassay used soil from two field sites with different soil types and land use histories. The number of colonized root tips was counted, and fungal species were identified using morphology, restriction fragment length polymorphism (RFLP), and DNA sequencing. Results showed that total ectomycorrhizal colonization varied more by soil type than by tree species. Individual fungal species varied in their colonization rates, but there were no significant differences between colonization on transgenic and wild-type chestnuts. This study shows that the oxalate oxidase gene can increase resistance againstCryphonectria parasiticawithout changing the colonization rate for ectomycorrhizal species. These findings will be crucial for a potential deregulation of blight-resistant American chestnuts containing the oxalate oxidase gene.

The influence of life history traits on the dispersal of ectomycorrhizal (EcM) fungi is reviewed. Spores are liberated from aboveground (epigeous) sporocarps through either ballistosporic discharge down to the ground (Basidiomycota) or bursting of asci up into the air (Ascomycota). Recent studies have shown that many spores fall close to the source sporocarp, increasing the probability of germinants coming into contact with compatible host roots and mating types but also potential competitors. Spores of both Ascomycota and Basidiomycota are also transported via wind, becoming increasingly diffuse with distance. Ascospores can establish new individuals from single spores as homokaryons, but a diffuse spore rain can reduce the chance for establishing dikaryons in new locations for Basidiomycota. Spores dispersed via mycophagist animals (hypogeous fungi, but also epigeous fungi such as Suillus) are transported to new locations in fecal material that can contain millions of spores and abundant compatible mating types. A few species in Suillus and Laccaria/Hydnagium are known to produce dikaryotic spores that can establish new individuals from single spores. Some species produce dormant sexual spores (Rhizopogon) or asexual chlamydospores (Wilcoxina) and sclerotia (Cenococcum). These propagules can build up over time as a resistant propagule bank in soils. Fungi that produce dormant propagules contribute to EcM success in early successional settings and help these fungi coinvade new locations with their hosts.

The first species of Rhizopogon subgenus Amylopogon identified from eastern North America is described here as Rhizopogon kretzerae Grubisha, Dowie, & Mill. sp. nov. In nature, R. kretzerae has been identified only from DNA sequences of the nuclear ribosomal internal transcribed spacer region (ITS) from mycorrhizal roots of Pinus strobus L. and Pterospora andromedea Nutt. Phylogenetic analyses and nucleotide divergence estimates of Rhizopogon ITS sequences from Pterospora roots from Quebec, Michigan, New York, and New Hampshire combined with ITS sequences of Rhizopogon subgenus Amylopogon species type collections suggest R. kretzerae is a sister-group to Rhizopogon salebrosus A.H. Sm. An absence of shared mutations, two informative sequence gaps, and 12 fixed nucleotide differences differentiate R. kretzerae and R. salebrosus. Furthermore, ITS sequences of 40 Pterospora root samples from five populations in the province of Quebec provided the first record of the distribution of R. kretzerae, a potentially rare to endangered species, in eastern Canada.

Dam (2013) critiques our paper, “95% of basidiospores fall within 1 m of the cap” (Galante et al. 2011). Our title was easily misconstrued to suggest we thought there was little long distance dispe...

Successional changes in belowground ectomy- corrhizal fungal (EMF) communities have been observed with increasing forest stand age; however, mechanisms behind this change remain unclear. It has been hypothe- sized that declines of inorganic nitrogen (N) and increases of organic N influence changes in EMF taxa over forest development. In a post-wildfire chronosequence of six jack pine (Pinus banksiana) stands ranging in age from 5 to 56 years, we investigated EMF community composition and compared shifts in taxa with detailed soluble inorganic and organic N data. Taxa were identified by internal transcribed spacer rDNA sequencing, and changes in community composition evaluated with non-metric multi- dimensional scaling (NMDS). Dissimilarities in the com- munity data were tested for correlations with N variables. We observed a successional shift along NMDS axis 1 from such taxa as Suillus brevipes and Thelephora terrestris in sites age 5 and 11 to species of Cortinarius and Russula, among others, in the four older sites. This change was positively correlated with soluble organic N (SON) (r 2 = 0.902, P = 0.033) and free amino-acid N (r 2 = 0.945, P = 0.021), but not inorganic N. Overall, our results show a successional shift of EMF communities occurring between stand initiation and canopy closure without a change in species of the dominant plant-host, and associ- ated with SON and free amino-acid N in soil. It is uncertain whether EMF taxa are responding to these organic N forms directly, affecting their availability, or are ultimately responding to changes in other site variables, such as belowground productivity.

Anthropogenic nitrogen (N) deposition alters ectomycorrhizal fungal communities, but the effect on functional diversity is not clear. In this review we explore whether fungi that respond differently to N deposition also differ in functional traits, including organic N use, hydrophobicity and exploration type (extent and pattern of extraradical hyphae). Cortinarius, Tricholoma, Piloderma, and Suillus had the strongest evidence of consistent negative effects of N deposition. Cortinarius, Tricholoma and Piloderma display consistent protein use and produce medium-distance fringe exploration types with hydrophobic mycorrhizas and rhizomorphs. Genera that produce long-distance exploration types (mostly Boletales) and contact short-distance exploration types (e.g., Russulaceae, Thelephoraceae, some athelioid genera) vary in sensitivity to N deposition. Members of Bankeraceae have declined in Europe but their enzymatic activity and belowground occurrence are largely unknown. Bankeraceae produce a distinct hydrophobic mat exploration type that may also be important in N acquisition under conditions of low N availability.

One of the greater challenges in conserving fungi comes from our incomplete knowledge of degree of rarity, risk status, and habitat requirements of most fungal species. We discuss approaches to immediately begin closing knowledge gaps, including: (1) harnessing collective expert knowledge so that data from professional experiences (e.g., personal collection and herbarium records) are better organized and made available to the broader mycological community; (2) thinking outside the mycology box by learning and borrowing from conservation approaches to other taxonomic groups; (3) developing and testing hypothesis-driven habitat models for representative fungi to provide support for habitat restoration and management; (4) framing ecological questions and conducting field surveys and research more directly pertinent to conservation information needs; and (5) providing adaptive management guidelines and strategies for resource managers to conserve fungi based on incrementally improving knowledge from experience and conservation research.

The presence and quality of the belowground mycorrhizal fungal community could greatly influence plant community structure and host species response. This study tests whether mycorrhizal fungal communities in areas highly impacted by anthropogenic disturbance and urbanization are less species rich or exhibit lower host root colonization rates when compared to those of less disturbed systems. Using a soil bioassay, we sampled the ectomycorrhizal fungal (EMF) communities associating with Quercus rubra (northern red oak) seedlings in soil collected from seven sites: two mature forest reference sites and five urban sites of varying levels of disturbance. Morphological and polymerase chain reaction-restriction fragment length polymorphism analyses of fungi colonizing root tips revealed that colonization rates and fungal species richness were significantly lower on root systems of seedlings grown in disturbed site soils. Analysis of similarity showed that EMF community composition was not significantly different among several urban site soils but did differ significantly between mature forest sites and all but one urban site. We identified a suite of fungal species that occurred across several urban sites. Lack of a diverse community of belowground mutualists could be a constraint on urban plant community development, especially of late-successional woodlands. Analysis of urban EMF communities can add to our understanding of urban plant community structure and should be addressed during ecological assessment before pragmatic decisions to restore habitats are framed.

Plant–soil feedbacks have been observed in many forest communities, but the role of the mycorrhizal community in perpetuating feedback loops is still poorly understood. Mycorrhizal community composition is closely linked to soil properties and host plant composition, which highlights their potential importance in plant–soil–fungus loops. Eastern hemlock (hemlock; Tsuga canadensis) seedlings were grown in soil bioassays in growth chambers and transplanted under closed forest canopy to examine the effect of hardwood and hemlock forest soil on seedling growth, survival, and ectomycorrhizal fungi (EMF) colonization. Seedlings propagated in hemlock forest soil had greater height growth compared with sterile control soil and achieved greater mycorrhizal colonization than seedlings grown in hardwood forest soils after 9 months in a growth chamber. Outplanted seedlings grown in hemlock communities achieved significantly greater increment growth than those seedlings grown in hardwood communities (mean height difference (95% CI) = 0.39 cm (0.14–0.63 cm)), although final survival and EMF colonization was similar between forest types. EMF diversity (Shannon-Wiener index (SE) = 1.88 (0.28) and 1.23 (0.44) for hardwood and hemlock, respectively) and community assemblage (Jaccard index (SE) = 19.0% (4%)) differed between the two forest communities. EMF community assemblage was associated with both the forest type (i.e. plant community/microsite effects) and initial soil type (i.e. soil characteristics/resistant inoculum). The results support previously observed positive feedbacks between conspecifics under hemlock forest communities and provides evidence for the role of the EMF community within this feedback loop. Alternatively, the reduced growth of hemlocks under hardwoods may be attributed to the different EMF community associated with that forest.

Summary 1. Almost all plants are engaged in symbiotic relationships with mycorrhizal fungi. These soil fungi can promote plant growth by supplying limiting nutrients to plant roots in return for plant assimilates. 2. Many mycorrhizal fungi are not host specific and one fungal individual can colonize and interconnect a considerable number of plants. The existence of these so-called mycorrhizal networks implies that fungi have the potential to facilitate growth of other plants and distribute resources among plants irrespective of their size, status or identity. In this paper, we explore the significance of mycorrhizal fungal networks for individual plants and for plant communities. 3. We address the following questions: (i) are all plant species benefitting from mycorrhizal networks, (ii) is benefit dependent on the size or age of a plant, (iii) is fungal support related to the relative dominance of plants in a community, (iv) are there host dependent barriers and physiological constraints for support and (v) what is the impact of mycorrhizal networks on plant–plant interactions and plant community dynamics? Moreover, using a review of published studies, we test whether mycorrhizal networks facilitate growth of small seedlings that establish between or near larger plants. 4. We found 60 cases where seedling species were grown together with larger plants with or without mycorrhizal fungal networks. Mycorrhizal networks promoted seedling growth in 48% of the cases (for 21 seedling species), while negative effects (25%) and no effects (27%) were also common. Seedlings associating with ectomycorrhizal fungi benefitted in the majority of the cases while effects on seedlings associating with arbuscular mycorrhizal fungi were more variable. Thus, the facilitative effects of mycorrhizal fungal networks depend on seedling species identity, mycorrhizal identity, plant species combinations and study system. We present a number of hypothetical scenarios that can explain the results based on cost–benefit relationship of individual members in a network. 5. Synthesis. Overall, this review shows that mycorrhizal networks play a key role in plant communities by facilitating and influencing seedling establishment, by altering plant–plant interactions and by supplying and recycling nutrients.

The establishment of common mycelial networks by mycorrhizal fungi shared between host plants depends on the ability of neighboring plants to enter into mycorrhizal associations with compatible fungal species. Such compatibility is governed by the potential mycorrhiza specificities of the symbionts. Mycorrhiza specificities exist along a continuum from low specificity (association with multiple partners) to high specificity (association with one or few partners). Although the ability of symbionts to form mycorrhizas may be largely governed by host-fungus gene interactions as influenced by co-evolutionary events, mycorrhizal associations in natural ecosystems can also be influenced by environmental factors (e.g. soil) and biological factors (e.g. different neighboring host species), phenomena referred to as “ecological specificity.” For example, in natural settings, mycorrhizal fungi often express “host preference” wherein fungi may be more common on a particular host in mixed-host settings than would be expected by random species assemblage within the fungal and plant communities. Mycorrhiza specificity phenomena significantly influence plant community dynamics, particularly plant succession. Early seral plants can positively affect the establishment of later-seral plants by maintaining commonly shared mycorrhizal fungi, and thus affecting the function of common mycelial networks over time. Such knowledge provides guidance for ecosystem managers to maintain “legacy” early -seral plants that benefit later-seral plants via shared mycorrhizal fungus species. Understanding specificity phenomena is also crucial for predicting the successful migration of plants and compatible mycorrhizal fungi during climate change. We review mycorrhiza specificity terminology and types of specificity phenomena, and suggest use of common terms to provide consistency in addressing this research topic. We also provide extensive examples from diverse ecosystems on the ability (or inability) of neighboring plants to develop common mycelial networks.

Like all obligately ectomycorrhizal plants, pines require ectomycorrhizal fungal symbionts to complete their life cycle. Pines introduced into regions far from their native range are typically incompatible with local ectomycorrhizal fungi, and, when they invade, coinvade with fungi from their native range. While the identities and distributions of coinvasive fungal symbionts of pine invasions are poorly known, communities that have been studied are notably depauperate. However, it is not yet clear whether any number of fungal coinvaders is able to support a Pinaceae invasion, or whether very depauperate communities are unable to invade. Here, we ask whether there is evidence for a minimum species richness of fungal symbionts necessary to support a pine/ectomycorrhizal fungus coinvasion. We sampled a Pinus contorta invasion front near Coyhaique, Chile, using molecular barcoding to identify ectomycorrhizal fungi. We report that the site has a total richness of four species, and that many invasive trees appear to be supported by only a single ectomycorrhizal fungus, Suillus luteus. We conclude that a single ectomycorrhizal (ECM) fungus can suffice to enable a pine invasion. Fil: Hayward, Jeremy. State University Of New York; Estados Unidos Fil: Horton, Thomas R.. State University Of New York; Estados Unidos Fil: Pauchard, Aníbal. Universidad de Concepción; Chile. Universidad de Chile; Chile Fil: Nuñez, Martin Andres. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina

The production of even a limited number of heterokaryotic spores would be advantageous for establishing new individuals after long distance dispersal. While Suillus and Laccaria species are known to produce binucleate, heterokaryotic spores, this condition is poorly studied for most ectomycorrhizal fungi. To begin addressing this matter the number of nuclei in basidiospores was recorded from 142 sporocarps in 63 species and 20 genera of ectomycorrhizal (EM) fungi. The mean proportion of binucleate basidiospores produced by sporocarps within a species ranged from 0.00 to 1.00, with most genera within a family showing similar patterns. Basidiospores from fungi in Amanita, Cortinariaceae and Laccaria were primarily binucleate but were likely still homokaryotic. Basidiospores from fungi in Boletaceae, Cantharellus, Rhizopogonaceae, Russulaceae, Thelephorales and Tricholoma were primarily uninucleate, but binucleate basidiospores were observed in many genera and in high levels in Boletus. Further research is needed to relate basidiospore nuclear number to reproductive potential in ectomycorrhizal species.

We investigated ectomycorrhizal (EM) fungi in forest stands containing both early successional Douglas-fir and late successional western hemlock at two points in the typical stand development by identifying EM fungi from roots of Douglas-fir and western hemlock in mixed stands. In an early seral stage forest, EM roots of western hemlock seedlings and intermingling 40-year-old Douglas-fir were sampled. In a late seral stage forest, EM roots of trees of both species were sampled in a 400-year-old stand. We use molecular approaches to identify the symbionts from field samples in this descriptive study. In the early seral stage study, >95% of the western hemlock root tips by biomass were colonized by fungi also colonizing Douglas-fir roots. This result supports the prediction that western hemlock can associate with fungi in Douglas-fir EM networks. In the same study, fungi specific to Douglas-fir colonized 14% of its EM root tips. In the late seral stage study, 14% of the western hemlock root tips were colonized by fungi also observed in association with Douglas-fir, a result strongly influenced by sampling issues and likely represents a conservative estimate of multiple host fungi in this old growth setting. Fungi specific to Douglas-fir colonized 25% of its root tip biomass in the old growth study, in tight coralloid clusters within five of the 24 soil samples. The trends revealed in this study corroborate earlier studies suggesting a predominance of multiple host fungi in mixed communities of EM plants. The role of host-specific fungi in these stands remains unclear.

Nitrogen availability may be a major factor structuring ectomycorrhizal fungal communities. Atmospheric nitrogen (N) deposition has been implicated in the decline of ectomycorrhizal fungal (EMF) sporocarp diversity. We previously characterized the pattern of decreased sporocarp species richness over an anthropogenic N deposition gradient in Alaska (USA). To determine whether this change in sporocarp community structure was paralleled below ground, we used molecular and morphological techniques to characterize the ectomycorrhizal community of white spruce (Picea glauca) over this gradient. We then related patterns of richness and relative abundance of taxa to various N-affected environmental parameters. Species richness of EMF declined dramatically with increasing N inputs. Over 30 taxa were identified at the low-N sites, compared with nine at the high-N sites. Low-N site dominants (Piloderma spp., Amphinema byssoides, Cortinarius spp., and various dark-mantled Tomentella spp.) disappeared completely at th...

Lisa C. Grubisha, Nicholas J. Dowie, Steven L. Miller, Christina Hazard, Steven M. Trowbridge, Thomas R. Horton, Matthew R. Klooster (2014): Rhizopogon kretzerae sp. nov.: the rare fungal symbiont in the tripartite system with Pterospora andromedea and Pinus strobus. Botany 92: 526-534, DOI: 10.1139/cjb-2013-0309

Rhizopogon kretzerae Grubisha, Dowie, & Mill. sp. nov. and. INDEX FUNGORUM REGISTRATION NUMBER : IF 550254 DIAGNOSIS : Known only from ectomycorrhizal symbioses with Pinus strobus and monotropoid mycorrhizal symbioses with the mycoheterotrophic plant Pterospora andromedea in eastern North America. Rhizopogon kretzerae can be distinguished from R. salebrosus, presently the closest identified species, by two indels found in the ITS1 and 12 fixed nucleotide differences, three in the ITS1 and nine in the ITS2. HOLOTYPE : DAOM 242738 LOCATION : United States of America, Michigan, Ottawa National Forest, 46.64271��N, 89.17873��W. Collection number: Miller 207, Collected: 4 August 2011 by N.J. Dowie and S.L. Miller. DAOM 242738 is a specimen from silica-dried, dead culture isolated from Pterospora andromedea roots, stored with silica. ETYMOLOGY : Named in honor of Dr. Annette Kretzer (State Univer- sity of New York, Syracuse, New York, USA), whose pioneering work on the population genetics of Rhizopogon vinicolor A.H. Sm. and Rhizopogon vesiculosus A.H. Sm. advanced our understanding of Rhizopogon evolutionary biology and provided inspiration to many mycologists and students. DESCRIPTION : Macroscopic and microscopic observations were made from a live culture of isolate Miller 207 but not the dried specimen that was deposited as the holotype because these notes were made after the dried holotype specimen was deposited at DAOM. MACROSCOPIC CHARACTERISTICS : Mycelial mat whitish at first (circa one week), aerial hyphae developing shades of pale brownish grey, older cultures (circa three weeks) pale reddish grey to gray- ish red, brownish orange, light brown or brown, often with patches of lighter color scattered across the colony (). Under U.V. light, light purple with dark purple patches; reverse brown, uniform, with radiating fans at the margin; mycelial mat floccose when first isolated, becoming low, dense, felty with age and with repeated transfers; margin irregular, whispy, aerial mycelium sparser toward edge, hyphae submerged at edge of colony when younger, submerged area overgrown on surface with fine hyphae in age, darker brown-like reverse appearing as a dark halo sur- rounding mycelial mat, minute knots of hyphae scattered to abundant at margin and throughout colony, concolorous with mycelium or lighter in color; maximum growth rate 3.0���3.4 cm in one month at 25 ��C; odor strong, sweet, and pleasant. MICROSCOPIC CHARACTERISTICS : Hyphae of interior of mycelial mat mostly 3���7 um, thick-walled, smooth, frequently swollen at sep- tations or forming vesciculose, catenulate cells, 6���33 ��m wide, thin-walled, easily collapsing; branching mostly simple, dendritic hyphae common; septae simple; clamps absent. Hyphae of ex- terior of mycelial mat mostly 3���10 ��m, cylindrical, branching simple, dendritic hyphae common, few swollen catenulate cells present, moderately thick-walled, heavily encrusted overall or in discreet patches with granular, pale brown pigment in KOH, in Melzer's Reagent pigment darker brown (dextriniod), soluble and floating free from the hyphal wall and appearing large globular or amorphous; septae simple; clamps absent. ECOLOGY AND DISTRIBUTION : Rhizopogon kretzerae appears to be re- stricted to areas with Pinus strobus and Pterospora andromedea or P. strobus alone in Northern Michigan, New York, New Hampshire, and southern Quebec. identified R. kretzerae from P. strobus roots within a P. andromedea rootball from Keweenaw County, Michigan. A soil bioassay study has shown that the frequency of R. kretzerae propagules in soil increases in P. strobus areas where P. andromedea is reproductively active with R. kretzerae occurring at a frequency from 6% of soil samples from sites with P. strobus to 14% to 25% (site vs. plot) in soils with both P. strobus and P. andromedea (). COMMENTS : Rhizopogon kretzerae is the first record of a Rhizopogon subgenus Amylopogon species that occurs in eastern North Amer- ica (i.e., east of the Mississippi River in US;;). Presently, there are no known annotated herbarium collections of the basidiocarp. Monotropoid mycorrhizal rootballs of eastern P. andromedea and R. kretzerae have diameters reaching a maximum of approximately 1.5 inches and are substantially smaller than rootballs of P. andromedea and R. salebrosus in western North America (). Ultrastructure of P. andromedea monotropoid roots has been described in detail by . OTHER SPECIMENS EXAMINED : Pterospora andromedea monotropoid mycorrhizal roots DAOM 242739, Location: Canada, province of Quebec, 45.4947��N, 76.3786��W; Collection number: Quebec A21, Collected: 26 July 2012 by M.R. Klooster and L.C. Grubisha; DAOM 242740, Location: Canada, province of Quebec, 45.4947��N, 76.3786��W; Collection number: Quebec A22, Collected: 26 July 2012 by M.R. Klooster and L.C. Grubisha; DAOM 242741, Location: Canada, province of Quebec, 47.2900��N, 79.4566��W, Collection number: Quebec D16, Collected 27 July 2012 by M.R. Klooster and L.C. Grubisha; DAOM 242742, Location: Canada, province of Quebec, 47.3166��N, 79.4533��W, Collection number: Quebec E22, Collected: 27 July 2012 by M.R. Klooster and L.C. Grubisha; DAOM 242743, Location: Canada, province of Quebec, 45.4672��N, 75.8069��W, Collection number: Quebec H11, Collected: 27 July 2012 by M.R. Klooster and L.C. Grubisha. All root samples were dried in silica gel. Discussion In this study, Rhizopogon kretzerae Grubisha, Dowie, & Mill., sp. nov. was described. This is also the first report of the distribution of this rare fungus in Quebec from five locations covering approximately 430 km. Since there are no known basidiocarp collections, the species description was based on ITS sequence data, ecological information, and a morphological description of the culture isolated from P. andromedea roots. The results from phylogenetic analyses presented here and in previous studies (;) are strong evidence that R. kretzerae is a species according to the phylogenetic species concept. If a basidiocarp is collected at some future time, the present description should be amended. Prior to this study, two GenBank environmental sequences (AF442136, DQ426677) had a>99% identity and both came to be known by some variation of the cumbersome phrase ���the unnamed species of Rhizopogon subgenus Amylopogon that associates with P. andromedea in the east��� (;), which can now be referred to as R. kretzerae. Furthermore, now it is possible to communicate ecological information about R. kretzerae if this species is found in environmental samples not associated with Pterospora in future studies of pines in eastern North America. Likewise, identification of R. kretzerae from soil near P. strobus may indicate the presence of potential candidate sites for Pterospora restoration efforts. Nucleotide divergence estimates provided a quantitative measure for comparing how sequences between species differ at the molecular level. In previous fungal studies, these statistics provided additional molecular evidence in support of speciation events in the Amanita muscaria complex (), Tricholoma scalpturatum complex (), and in identifying two lineages of cryptic species in Tricholoma populinum ( ). In this study, R. kretzerae and R. salebrosus are separated by the fewest number of fixed nucleotide differences (12) that support an apparent sister-group relationship in the unrooted phylogeny (). A phylogeny with an outgroup was not shown due to the large number of gaps and ambiguously aligned positions that needed to be removed for analyses, which would have removed too many informative positions within the ingroup. Phylogenetic assessments of species in Rhizopogon subgenus Amylopogon based on multiple nuclear loci are currently underway (N.J. Dowie, unpublished data). The lack of historic collections of basidiocarps in herbaria or collection by contemporary researchers of Pterospora or Rhizopogon may stem from a variety of reasons. This species may no longer reproduce sexually in nature due to severely altered environmental conditions (e.g., fire suppression), or alternatively, basidiocarps are produced but (1) at a time when no one has searched for them (e.g., early or late in the fruiting season); (2) are deeper in the soil profile than is typical for finding Rhizopogon basidiocarps; or (3) at a very low frequency and less likely to be collected. Hypothesis 3 is supported by the low frequency in which R. kretzerae has been identified in soil bioassays () when compared with similar studies on western North America Rhizopogon species (;). In this study, two strategies were implemented to avoid naming an already described species. First, 22 ITS holotype and paratype sequences of Rhizopogon subgenus Amylopogon were retrieved from GenBank for phylogenetic comparison to R. kretzerae (). Second, partial to entire ITS sequences were determined from four Rhizopogon holotypes collected in Michigan that were associated with Pinus spp., but subsequently shown to belong to Rhizopogon subgenera other than subgenus Amylopogon. These results support who had synonymized R. superiorensis with R. succossus. In the case of R. baxteri, Zeller had originally identified the collection Baxter2578 as R. rubescens (see original herbarium card; ). Owing to the high similarity of Baxter2578 with R. rubescens and R. roseolus sequences, it is unclear whether R. baxteri is a unique species; however, this, along with determining the taxonomic status of R. gelatinosus MICH 3268 and holotypes R. gelatinosus MICH 12392 and R. pinicola MICH 12404 will be left for investigation in future studies as it is beyond the scope of the current study. The ITS2 primers introduced here (R370F and R536R) may be useful in future studies of historic Rhizopogon collections. Pterospora andromedea populations in Quebec were reproductively active in July 2012 despite a widespread drought in southeastern Canada. We found plants at five out of seven sites visited based on 10 historic Pterospora locations listed on the collecting permit provided by Quebec's provincial government. Four of five sites had more than 10 plants, but only one site had more than 20 plants. Stems from 2011 were present at all sites that had flowering plants in 2012, but were equal or fewer in number to those counted in 2012. However, the total number of stems present in 2012 at these five sites was lower than in previous records (24���270) provided on the collecting permit. The low number to complete absence of plants observed in 2012 could have been the result of: (i) the severe drought, (ii) a simple reflection of the sporadic nature of the flowering pattern in Pterospora, in which the plant is abundant in some years and completely absent in others, similar to the fruiting pattern of some fungi, or (iii) an indication that the Quebec populations are in serious decline, as has been shown in other eastern populations. Continued monitoring of Pterospora sites, historic and contemporary, is necessary to gain a better understanding of the ecology and reproductive biology of this species. This work is the first installment of a series of conservation genetics and phylogeographic studies of eastern and western populations of Pterospora andromedea and Rhizopogon symbionts. Conservation management plans and scientific studies may now refer to this potentially rare fungal species as Rhizopogon kretzerae, instead of the formerly used name ���the undescribed Rhizopogon subgenus Amylopogon species that associates with Pterospora andromedea in the east���., Published as part of Lisa C. Grubisha, Nicholas J. Dowie, Steven L. Miller, Christina Hazard, Steven M. Trowbridge, Thomas R. Horton & Matthew R. Klooster, 2014, Rhizopogon kretzerae sp. nov.: the rare fungal symbiont in the tripartite system with Pterospora andromedea and Pinus strobus, pp. 526-534 in Botany 92 on pages 531-533, DOI: 10.1139/cjb-2013-0309, http://zenodo.org/record/246791

Ecological interactions are frequently conserved across evolutionary time. In the case of mutualisms, these conserved interactions may play a large role in structuring mutualist communities. We hypothesized that phylogenetic trait conservation could play a key role in determining patterns of association in the ectomycorrhizal symbiosis, a globally important trophic mutualism. We used the association between members of the pantropical plant tribe Pisonieae and its fungal mutualist partners as a model system to test the prediction that Pisonieae-associating ectomycorrhizal fungi will be more closely related than expected by chance, reflecting a conserved trait. We tested this prediction using previously published and newly generated sequences in a Bayesian framework incorporating phylogenetic uncertainty. We report that phylogenetic trait conservation does exist in this association. We generated a five-marker phylogeny of members of the Pisonieae and used this phylogeny in a Bayesian relaxed molecular clock analysis. We established that the most recent common ancestors of Pisonieae species and Pisonieae-associating fungi sharing phylogenetic conservation of their patterns of ectomycorrhizal association occurred no more recently than 14.2 Ma. We therefore suggest that phylogenetic trait conservation in the Pisonieae ectomycorrhizal mutualism association represents an inherited syndrome which has existed for at least 14 Myr.

Alpova diplophloeus (Boletales, Paxillaceae) is the only currently recognized Alpova in North America with a brownish peridium, large gleba chambers and which forms ectomycorrhizas with Alnus. However, A. diplophloeus as currently circumscribed is a polyphyletic species, with at least three distinct genetic entities. Using a combination of molecular and morphological characters, we examined the type collections of A. diplophloeus, as well as species synonymized with it, including A. cinnamomeus and Rhizopogon parvisporus. We also examined several other collections of A. diplophloeus complex basidiomata. We describe A. diplophloeus sensu stricto; we also resurrect A. cinnamomeus, synonymized with R. parvisporus and describe a new species, A. concolor, from the complex.

Exotic pine plantations are promoted for their presumed capacity to provide a net sink of atmospheric C. Millions of hectares worldwide will be subjected to conversion into plantations during the next decades. However, pine introductions are known to result in a marked depletion of soil C, a phenomenon which has remained unexplained. We studied plantations in paramo grasslands of Ecuador, where the effect of the exotic introduction of radiata pines ( Pinus radiata ) and their accompanying ectomycorrhizal fungi can be studied in isolation from other ecosystem disturbances. We suggest that ectomycorrhizal fungi can extract C previously accumulated by paramo grasslands based on (a) a drastic simplification of the ectomycorrhizal community shown by direct DNA identification, (b) a loss of up to 30% soil C within 2 levels.

Molecular tools have now been applied for the past 5 years to dissect ectomycorrhizal (EM) community structure, and they have propelled a resurgence in interest in the field. Results from these studies have revealed that: (i) EM communities are impressively diverse and are patchily distributed at a fine scale below ground; (ii) there is a poor correspondence between fungi that appear dominant as sporocarps vs. those that appear dominant on roots; (iii) members of Russulaceae, Thelephoraceae, and/or non-thelephoroid resupinates are among the most abundant EM taxa in ecosystems sampled to date; (iv) dissimilar plants are associated with many of the same EM species when their roots intermingle — this occurs on a small enough spatial scale that fungal individuals are likely to be shared by dissimilar plants; and (v) mycoheterotrophic plants have highly specific fungal associations. Although, these results have been impressive, they have been tempered by sampling difficulties and limited by the taxonomic resolution of restriction fragment length polymorphism methods. Minor modifications of the sampling schemes, and more use of direct sequencing, has the potential to solve these problems. Use of additional methods, such as in situ hybridization to ribosomal RNA or hybridization coupled to microarrays, are necessary to open up the analysis of the mycelial component of community structure.

The eects of a prescribed fire on the presence of ectomycorrhizal fungi on the root tips of ponderosa pine were investigated one year after a prescribed ground fire. Ectomycorrhizas were sampled within 1 m# plots before and one year after the fire, and in nearby control plots that were not burned. The cores were divided into litter}organic, upper mineral, and lower mineral layers. The total ectomycorrhizal biomass in the control plots did not dier between year one and year two samples for any core layer, while in the fire plots the destruction of the litter}organic layer resulted in an eight-fold reduction in total ectomycorrhizal biomass. Mycorrhizal biomass in the two mineral layers was not significantly reduced by the fire. We used molecular tools to identify fungi directly from the ectomycorrhizas. In unburned plots members of the Russulaceae and Thelephoraceae were among the most frequent and abundant ectomycorrhizal types; species of most other taxa were rare. In the control plots these two families were among the dominant species in both years, but patchiness on a fine spatio-temporal scale caused some major changes in ranking of individual species between sample years. Rhizopogon subcaerulescens was the most pronounced example; its biomass in the control plot samples was seven times greater in year two than in year one because of an exceptionally large cluster of mycorrhizas encountered in a single core. The eect of fire on individual species was dicult to assess because of this patchiness and because all species were low in abundance after the fire. The most abundant pre-fire species were reduced to undetectable post-fire levels, while several less abundant species, including R. subcaerulescens, Cenococcum geophilum, and several unknown types were not substantially reduced by the fire. We speculate that the more abundant species, Martellia sp., thelephoroid 1, and Tomentella sublilacina, were dierentially aected because their dominance was most prominent at the litter and organic layers. In any case, a short-term eect of this fire appears to be increased species evenness.

Chaparral on the central coast of California can occur as relatively stable patches of ectomycorrhizal Arctostaphylos directly adjacent to arbuscular mycorrhizal Adenostoma. Vegetation surveys and seedling survival assays show that Pseudotsuga establishes only in Arctostaphylos. We found no significant differences between Arctostaphylos and Adenostoma in allelopathy; light; temperature; or soil NH4+, NO3-, or K. Arctostaphylos soils tended to be higher in phosphate and were lower in pH, Ca, Mg, Ni, and Cr than those from Adenostoma. After 1 year of growth of Pseudotsuga seedlings in an Arctostaphylos patch, 17 species of fungi colonized both Pseudotsuga and Arctostaphylos. Fifty-six of 66 seedlings were colonized by fungi that also colonized Arctostaphylos within the same soil core. Forty-nine percent of the Pseudotsuga ectomycorrhizal biomass was colonized by fungi that were also associated with Arctostaphylos within the same core. Another 12% was colonized by fungi known to associate with Arctostaphylos from different cores. After 4 months of growth, Pseudotsuga seedlings in four of five Arctostaphylos plots were ectomycorrhizal and colonized by fungi in Russulaceae, Thelephoraceae, and Amanitaceae. Pseudotsuga seedlings in two of five Adenostoma plots were ectomycorrhizal but colonized by only two species of fungi in Thelephoraceae. These results provide compelling evidence that ectomycorrhizal fungi associated with Arctostaphylos contribute to Pseudotsuga seedling establishment.Key words: arbutoid, Douglas-fir, ectomycorrhizae, manzanita, RFLP, PCR.

Keywords FESIN.ESA.Fungi.EnvironmentalsamplingThe first large public meeting of the Fungal EnvironmentalSampling and Informatics Network (FESIN: http://www.bio.utk.edu/fesin/title.htm) took place at the EcologicalSociety of America (ESA) meetings in Milwaukee thissummer. Last year’s meetings at the Mycological Society ofAmerica (MSA) and ESA meetings were mostly informa-tional, highlighting future activities of this NSF-sponsoredresearch coordination network. A joint meeting betweenFESIN and the User-friendly Nordic ITS Ectomycorrhizalgroup (UNITE) also occurred last year to spearheadresearch proposals, and discuss pros and cons of currentmethods for analyzing fungal communities (Bruns et al.2008). This year’s meeting included 2 days of preconferenceworkshops that are summarized below. In addition, JeriParrentandBetsyArnoldorganizedaFESIN-sponsoredoralsession entitled ‘Frontiers in the Ecology of Plant–FungalInteractions,’ held during the main ESA meeting. Thissession brought together mycologists and ecologists in astanding-room-only series of eleven talks (see authors andabstracts at http://eco.confex.com/eco/2008/techprogram/S2894.HTM).The 2008 FESIN meeting was a big success judged bylevel of attendance, composition of attendees, and directfeedback that the organizers received. Ninety peopleattended the workshops; of these, 58% were either graduatestudents or postdocs. A show of hands revealed that overhalf of those attending had never been to an ESA meetingbefore; an equal number had never attended a MSAmeeting. This was great news given that one of the goalsof FESIN is to increase connections between ecologists andmycologists and to bring new people and ideas into thegrowing field of fungal ecology.Jeri Parrent, Kitty Gehring, Karen Hughes, BetsyArnold, and Tom Bruns organized the preconferenceworkshops. The goal of Saturday’s workshop was tointroduce appropriate molecular techniques to ecologistswho are just beginning to work on fungi, and to introducenew methodological advances to those already familiar withthe basics. The first set of talks by Mary Berbee, JeriParrent, Ian Dickie, and Shannon Schechter introducedFungi as a group, the suite of major molecular techniquesused to study them, and specialized problems associatedwith studying arbuscular mycorrhizal fungi. Then, AriJumpponen, Cedar Hesse, and Jason Stajich described high-throughput sequencing for studying fungal communities, andprovided an up-to-date perspective on bioinformatics tools.Brendan Bohannan and Ian Alexander addressed the prob-lemsofsamplinghyper-diversecommunitiesthatexhibithighspatial–temporalvariation,andChrisSchadtdiscussedtheuseof functional gene arrays to study the “process” level ofcommunities.Sunday’s workshop focused on the strengths, weak-nesses, and opportunities offered by public sequence

summary The ectomycorrhizal fungal associations of Douglas fir (Pseudotsuga menziesii D. Don) and bishop pine (Pinus muricata D. Don) were investigated in a mixed forest stand. We identified fungi directly from field-collected ectomycorrhizal (ECM) root tips using PCR-based methods. Sixteen species of fungi were found, of which twelve associated with both hosts. Rhizopogon parksii Smith was specific to Douglas fir. Three other species colonized only one of the hosts, but were too infrequent to draw conclusions about specificity. Seventy-four percent of the biomass of ECM root tips sampled in the stand were colonized by members of the Thelephoraceae and Russulaceae. All 12 species of fungi that associated with both tree species did so within a 10‹40 cm soil volume, suggesting that individual fungal genotypes linked the putatively competing tree hosts.

We have assembled a sequence database for 80 genera of Basidiomycota from the Hymenomycete lineage (sensu Swann & Taylor 1993) for a small region of the mitochondrial large subunit rRNA gene. Our taxonomic sample is highly biased toward known ectomycorrhizal (EM) taxa, but also includes some related saprobic species. This gene fragment can be amplified directly from mycorrhizae, sequenced, and used to determine the family or subfamily of many unknown mycorrhizal basidiomycetes. The method is robust to minor sequencing errors, minor misalignments, and method of phylogenetic analysis. Evolutionary inferences are limited by the small size and conservative nature of the gene fragment. Nevertheless two interesting patterns emerge: (i) the switch between ectomycorrhizae and saprobic lifestyles appears to have happened convergently several and perhaps many times; and (ii) at least five independent lineages of ectomycorrhizal fungi are characterized by very short branch lengths. We estimate that two of these groups radiated in the mid-Tertiary, and we speculate that these radiations may have been caused by the expanding geographical range of their host trees during this period. The aligned database, which will continue to be updated, can be obtained from the following site on the WorldWide Web: http://mendel.berkeley.edu/boletus.html.

American chestnut (Castanea dentata) was once a dominant overstory tree in eastern USA but was decimated by chestnut blight (Cryphonectria parasitica). Blight-resistant chestnut is being developed as part of a concerted restoration effort to bring this heritage tree back. Here, we evaluate the potential of field soils in the northern portion of the chestnut's former range to provide ectomycorrhizal (EM) fungus inoculum for American chestnut. In our first study, chestnut seedlings were grown in a growth chamber using soil collected from three sites dominated by red oak (Quercus rubra) as inoculum and harvested after 5 months. Of the 14 EM fungi recovered on these seedlings, four species dominated in soils from all three sites: Laccaria laccata, a Tuber sp., Cenococcum geophilum, and a thelephoroid type. Seedlings grown in the nonsterilized soils were smaller than those growing in sterilized soils. In the second study, chestnut seedlings were grown from seed planted directly into soils at the same three sites. Seedlings with intermingling roots of established trees of various species were harvested after 5 months. Seventy-one EM fungi were found on the root tips of the hosts, with 38 occurring on chestnut seedlings. Multiple versus single host EM fungi were significantly more abundant and frequently encountered. The fungi observed dominating on seedlings in the laboratory bioassay were not frequently encountered in the field bioassay, suggesting that they may not have been active in mycelial networks in the field setting but were in the soils as resistant propagules that became active in the bioassay. These results show that soil from red oak stands can be used to inoculate American chestnut with locally adapted ectomycorrhizal fungi prior to outplanting, a relatively cost effective approach for restoration efforts.

Like other myco-heterotrophic plants, Pterospora andromedea (pinedrops) is dependent upon its specific fungal symbionts for survival. The rarity of pinedrops fungal symbiont was investigated in the eastern United States where pinedrops are rare. Wild populations of eastern pinedrops were sampled, and the plant haplotypes and fungal symbionts were characterized with molecular techniques; these data were compared to those from the West with phylogenetic analyses. The frequency of the fungal symbiont in eastern white pine forests was assessed using a laboratory soil bioassay and in situ pinedrops seed baiting. Only one plant haplotype and fungal symbiont was detected. The plant haplotype was not unique to the East. The fungal symbiont appears to be a new species within the genus Rhizopogon, closely related to the western symbionts. This fungal species was not frequent in soils with or without pinedrops, but was less frequent in the latter and in comparison to the fungal symbionts in western forests. Seed baiting resulted in few germinants, suggesting that mycelial networks produced by the eastern fungal symbiont were rare. Results suggest that eastern pinedrops rarity is influenced by the distribution and rarity of its fungal symbiont.

Plant establishment patterns suggest that ectomycorrhizal fungal (EMF) inoculant is not found ubiquitously. The role of animal vectors dispersing viable EMF spores is well documented. Here we investigate the role of wind in basidiospore dispersal for six EMF species, Inocybe lacera, Laccaria laccata, Lactarius rufus, Suillus brevipes, Suillus tomentosus and Thelephora americana. Basidiospores adhered to microscope slides placed on three 60 cm transects radiating from sporocarps. Morphological character- istics of species as well as average basidiospore volume were recorded. Number of basidiospores was quanti- fied at specific distances to produce actual dispersal gradients. We found a negative exponential decay model using characteristics for each species fit the field data well. The 95% modeled downwind dispersal distance of basidiospores was calculated for each species. The 95% modeled downwind dispersal distance increased with increasing cap height and decreasing basidiospore volume for the species sampled, with 95% of basidiospores predicted to fall within 58 cm of the cap. Differences in anatomical characteristics of EMF species influence how far basidiospores are dispersed by wind. We discuss the role of wind dispersal leading to patterns of EMF establishment during primary succession.

Why particular invasions succeed and others fail is not well understood. The role of soil biota has been proposed as important. However, the role of mutualists has received much less attention than that of pathogens. Here we report that lack of adequate ectomycorrhizal fungi hinders invasion by exotic Pinaceae on Isla Victoria, Argentina, by reducing both the probability of establishment and growth of invading individuals. More than one hundred exotic tree species were introduced to this island ca. 80 years ago, but invasive trees are found in high densities only in areas adjacent to plantations. With a series of greenhouse and field experiments we found lower mycorrhizal colonization levels and few fungal species far from original plantings, and key fungal mutualists are confined to areas near plantations, probably owing to dispersal limitations. Low inoculum levels far from the plantations are retarding the invasion. Our experiments indicate that positive interactions belowground can play a key but underappreciated role in invasion dynamics.

Ectomycorrhizal fungal (EMF) communities are highly diverse at the stand level. To begin to understand what might lead to such diversity, and to improve sampling designs, we investigated the spatial structure of these communities. We used EMF community data from a number of studies carried out in seven mature and one recently fire-initiated forest stand. We applied various measures of spatial pattern to characterize distributions at EMF community and species levels: Mantel tests, Mantel correlograms, variance/mean and standardized variograms. Mantel tests indicated that in four of eight sites community similarity decreased with distance, whereas Mantel correlograms also found spatial autocorrelation in those four plus two additional sites. In all but one of these sites elevated similarity was evident only at relatively small spatial scales (2.6 m), whereas one exhibited a larger scale pattern ( approximately 25 m). Evenness of biomass distribution among cores varied widely among taxa. Standardized variograms indicated that most of the dominant taxa showed patchiness at a scale of less than 3 m, with a range from 0 toor =17 m. These results have implications for both sampling scale and intensity to achieve maximum efficiency of community sampling. In the systems we examined, cores should be at least 3 m apart to achieve the greatest sampling efficiency for stand-level community analysis. In some cases even this spacing may result in reduced sampling efficiency arising from patterns of spatial autocorrelation. Interpretation of the causes and significance of these patterns requires information on the genetic identity of individuals in the communities.

Summary • Ectomycorrhizal fungi (EMF) are critical for pine establishment under primary succession. The species of EMF supporting primary successional pine seedlings on coastal sand dunes and mechanisms for their establishment were investigated. • Fungi were identified from ectomycorrhizal roots using molecular techniques. Field seedlings were collected from forested and nonforested zones. Laboratory seedlings were grown in soils collected from the same zones, and in sterile soils inoculated with fresh and 1-yr-old dry deer fecal pellets. • Suilloid fungi were frequently observed on all seedlings. A diverse group of fungi was available to seedlings in forested zones. A less diverse group of fungi was available to field seedlings in nonforested zones and all laboratory bioassay seedlings. Deer fecal inoculant yielded an average of two EMF per seedling. Both Suillus and Rhizopogon species dominated seedlings inoculated with fresh deer feces, but only Rhizopogon species dominated seedlings inoculated with 1-yr-old feces. • Suilloid fungi are dispersed by deer, produce resistant spore banks and are the principle fungi supporting seedlings on the sand dunes.

The objective of this study was to determine patterns of ectomycorrhizas (ECM) and arbuscular mycorrhizas (AM) colonization associated with Alnus acuminata (Andean alder), in relation to soil parameters (electrical conductivity, field H2O holding capacity, pH, available P, organic matter, and total N) at two different seasons (autumn and spring). The study was conducted in natural forests of A. acuminata situated in Calilegua National Park (Jujuy, Argentina). Nine ECM morphotypes were found on A. acuminata roots. The ECM colonization was affected by seasonality and associated positively with field H2O holding capacity, pH, and total N and negatively associated with organic matter. Two morphotypes (Russula alnijorullensis and Tomentella sp. 3) showed significant differences between seasons. Positive and negative correlations were found between five morphotypes (Alnirhiza silkacea, Lactarius omphaliformis, Tomentella sp. 1, Tomentella sp. 3, and Lactarius sp.) and soil parameters (total N, pH, and P). A significant negative correlation was found between field H2O holding capacity and organic matter with AM colonization. Results of this study provide evidence that ECM and AM colonization of A. acuminata can be affected by some soil chemical edaphic parameters and indicate that some ECM morphotypes are sensitive to changes in seasonality and soil parameters. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Zak, Marcelo Román. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Empresarial Siglo XXI; Argentina Fil: Horton, Thomas R.. College of Environmental Science and Forestry; Estados Unidos Fil: Micolini, Jorge. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina

Post-fire Pezizales fruit commonly in many forest types after fire. The objectives of this study were to determine which Pezizales appeared as sporocarps after a prescribed fire in the Blue Mountains of eastern Oregon, and whether species of Pezizales formed mycorrhizas on ponderosa pine, whether or not they were detected from sporocarps. Forty-two sporocarp collections in five genera (Anthracobia, Morchella, Peziza, Scutellinia, Tricharina) of post-fire Pezizales produced ten restriction fragment length polymorphism (RFLP) types. We found no root tips colonized by species of post-fire Pezizales fruiting at our site. However, 15% (6/39) of the RFLP types obtained from mycorrhizal roots within 32 soil cores were ascomycetes. Phylogenetic analyses of the 18S nuclear ribosomal DNA gene indicated that four of the six RFLP types clustered with two genera of the Pezizales, Wilcoxina and Geopora. Subsequent analyses indicated that two of these mycobionts were probably Wilcoxina rehmii, one Geopora cooperi, and one Geopora sp. The identities of two types were not successfully determined with PCR-based methods. Results contribute knowledge about the above- and below-ground ascomycete community in a ponderosa pine forest after a low intensity fire.

Ramaria species are conspicuous mycorrhizal symbionts of conifers in the Pacific Northwest. Here we collected and identified sporocarps and associated ectomycorrhizae of Ramaria acrisiccescens Marr & Stuntz, R. cyaneigranosa Marr & Stuntz, R. sandracina Marr & Stuntz, R. celerivirescens Marr & Stuntz, and R. flavobrunnescens var. aromatica Marr & Stuntz. An internal transcribed spacer (ITS)- restriction fragment length polymorphism pattern was observed for each of the Ramaria species and used as a diagnostic tool to support the identification of mycorrhizae occurring in mats below the sporocarps. We provide a description of the ectomycorrhizae of Ramaria, which exhibit similar macro- and microscopic characteristics such as ramification pattern, coloration, abundance of mycelial strands and emanating hyphae, mantle morphology and chemical reactions of mantle and mycelial strands with KOH, Fe SO4 and Melzer´s reagent. Sequences of the ITS region for each of the species are deposited in the Gen Bank. Fil: Nouhra, Eduardo Ramon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Horton, Thomas R.. College of Enviromental Science and Forestry; Estados Unidos Fil: Cazares, Efren. State University of Oregon; Estados Unidos Fil: Castellano, Michael. United State Department of Agriculture; Estados Unidos

Host–Fungus Associations Structure and Function Ecology of Ectomycorrhizae Ecosystem Functions Physiology Practical Applications in Forestry Keywords: ectomycorrhizal fungi; fungi; mycorrhizae