Rhizoscyphus Ericae Research Articles

Investigation of neomycin biodegradation conditions using ericoid mycorrhizal and white rot fungal species

BackgroundIn the search for methods to biodegrade recalcitrant compounds, the use of saprotrophic fungi and white rot fungi, in particular belonging to the phylum Basidiomycota, has gained interest. This group of fungi possesses a battery of unspecific extracellular enzymes that can be utilized in the biodegradation of preferably phenolic compounds. In this work, it was investigated under which conditions the white rot fungus Trametes versicolor and the ericoid mycorrhizal fungus Rhizoscyphus ericae (belonging to the phylum Ascomycota) could be used to biodegrade the antibiotic aminoglycoside neomycin at co-metabolic conditions in which external nutrients were supplied. Furthermore, it was also investigated whether a biodegradation could be accomplished using neomycin as the sole nutrient.ResultsThe results show that both species can biodegrade neomycin 70% under co-metabolic conditions during a one-week time course and that Rhizoscyphus ericae is able to use neomycin as sole nutrient and to approximatively biodegrade it 60% under chosen non co-metabolic conditions.At selected conditions, the biodegradation of neomycin using Rhizoscyphus ericae was monitored by oxidation products of D-ribose which is a hydrolysis product of neomycin.ConclusionThe results are of general interest in the search for fungal species that can biodegrade recalcitrant compounds without the need of external nutrients. The key future application area that will be investigated is purification of waste from recombinant protein production in which neomycin, nutrients and E. coli with neomycin resistance genes are present.

Survival and growth of saprotrophic and mycorrhizal fungi in recalcitrant amine, amide and ammonium containing media.

The elimination of hazardous compounds in chemical wastes can be a complex and technically demanding task. In the search for environmental-friendly technologies, fungal mediated remediation and removal procedures are of concern. In this study, we investigated whether there are fungal species that can survive and grow on solely amine-containing compounds. One compound containing a primary amine group; 2-diethylaminoethanol, one compound with a primary amide group; 2,6-dichlorobenzamide (BAM), and a third compound containing a quaternary ammonium group; N3-trimethyl(2-oxiranyl)methanaminium chloride, were selected. The choice of these compounds was motivated by their excessive use in large scale manufacturing of protein separation media (2-diethylaminoethanol and the quaternary amine). 2,6-dichlorobenzamide, the degradation product of the herbicide 2,6-dichlorobenzonitrile (dichlobenil), was chosen since it is an extremely recalcitrant compound. Utilising part of the large fungal diversity in Northern European forests, a screening study using 48 fungal isolates from 42 fungal species, including saprotrophic and mycorrhizal fungi, was performed to test for growth responses to the chosen compounds. The ericoid (ERM) mycorrhizal fungus Rhizoscyphus ericae showed the best overall growth on 2-diethylaminoethanol and BAM in the 1-20 g L-1 concentration range, with a 35-fold and 4.5-fold increase in biomass, respectively. For N3-trimethyl(2-oxiranyl)methanaminium chloride, the peak growth occurred at 1 g L-1. In a second experiment, including three of the most promising fungi (Laccaria laccata, Hygrophorus camarophyllus and Rhizoscyphus ericae) from the screening experiment, a simulated process water containing 1.9% (w/v) 2-diethylaminoethanol and 0.8% (w/v) N3-trimethyl(2-oxiranyl)methanaminium chloride was used. Laccaria laccata showed the best biomass increase (380%) relative to a control, while the accumulation for Rhizoscyphus ericae and Hygrophorus camarophyllus were 292% and 136% respectively, indicating that mycorrhizal fungi can use amine- and amide-containing substrates as nutrients. These results show the potential of certain fungal species to be used in alternative green wastewater treatment procedures.

Effects of one dark septate endophytic fungal and two Helotiales strains on the growth of plane-leaved willow (Salix planifolia) cuttings on iron ore waste rock

Plants maintain beneficial mutualistic relationships with the mycobiont communities found in their rhizosphere, leading to an increase in plant productivity and health. In nutrient-depleted substrates like mine tailings, mycobiont inoculation is often recommended to help restore a successful plant cover. Our 15-week greenhouse experiment aimed to assess the individual effects of a dark septate endophyte (Phialocephala fortinii C.J.K. Wang & H.E. Wilcox #4 (KX611529)) and two Helotiales strains (Rhizoscyphus ericae (D.J. Read) W.Y. Zhuang & Korf #22 (EU221877) and Meliniomyces sp. #1 (KT275679)) on the growth of plane-leaved willow (Salix planifolia Pursh) cuttings on sterilized and unsterilized waste rock. Rhizoscyphus ericae increased shoot biomass of cuttings on sterilized waste rock, whereas Meliniomyces sp. had a positive effect on cuttings grown on unsterilized waste rock. However, P. fortinii strain had no effect on the survival rate, shoot production, and biomass production of S. planifolia cuttings. This study demonstrates that controlled inoculation with ecologically well-adapted mycobionts could promote plant establishment and productivity on abandoned waste rock and could be an efficient and integrated biotechnological approach for ecological restoration of Canadian mining boreal ecosystems.

Advances in understanding of mycorrhizal-like associations in bryophytes

Mutually beneficial associations between plants and soil fungi, mycorrhizas, are one of the most important terrestrial symbioses. These partnerships are thought to have propelled plant terrestrialisation some 500 million years ago and today they play major roles in ecosystem functioning. It has long been known that bryophytes harbour, in their living tissues, fungal symbionts, recently identified as belonging to the three mycorrhizal fungal lineages Glomeromycotina, Ascomycota and Basidiomycota. Latest advances in understanding of fungal associations in bryophytes have been largely driven by the discovery, nearly a decade ago, that early divergent liverwort clades, including the most basal Haplomitriopsida, and some hornworts, engage with a wider repertoire of fungal symbionts than previously thought, including endogonaceous members of the ancient sub-phylum Mucoromycotina. Subsequent global molecular and cytological studies have revealed that Mucoromycotina symbionts, alongside Glomeromycotina, are widespread in both complex and simple thalloid liverworts and throughout hornworts, with physiological studies confirming that, in liverworts at least, these associations are mycorrhizal-like, and highlighting important functional differences between Mucoromycotina and Glomeromycotina symbioses. Whether a more prominent role of Mucoromycotina symbionts in plant nitrogen nutrition, as identified in liverworts, extends to other plant lineages, including the flowering plants, is a major topic for future research.
 The latest finding that ascomycete symbionts of leafy liverworts are not restricted to one fungus, Rhizoscyphus ericae, but include species in the genus Meliniomyces, as shown here in Mylia anomala, together with the recent demonstration that R. ericae forms nutritional mutualisms with the rhizoids of Cephalozia bicuspidata, fill other major gaps in our growing knowledge of fungal associations across land plants.

The root-symbiotic Rhizoscyphus ericae aggregate and Hyaloscypha (Leotiomycetes) are congeneric: Phylogenetic and experimental evidence.

Data mining for a phylogenetic study including the prominent ericoid mycorrhizal fungus Rhizoscyphus ericae revealed nearly identical ITS sequences of the bryophilous Hyaloscypha hepaticicola suggesting they are conspecific. Additional genetic markers and a broader taxonomic sampling furthermore suggested that the sexual Hyaloscypha and the asexual Meliniomyces may be congeneric. In order to further elucidate these issues, type strains of all species traditionally treated as members of the Rhizoscyphus ericae aggregate (REA) and related taxa were subjected to phylogenetic analyses based on ITS, nrLSU, mtSSU, and rpb2 markers to produce comparable datasets while an in vitro re-synthesis experiment was conducted to examine the root-symbiotic potential of H. hepaticicola in the Ericaceae. Phylogenetic evidence demonstrates that sterile root-associated Meliniomyces, sexual Hyaloscypha and Rhizoscyphus, based on R. ericae, are indeed congeneric. To this monophylum also belongs the phialidic dematiaceous hyphomycetes Cadophora finlandica and Chloridium paucisporum. We provide a taxonomic revision of the REA; Meliniomyces and Rhizoscyphus are reduced to synonymy under Hyaloscypha. Pseudaegerita, typified by P. corticalis, an asexual morph of H. spiralis which is a core member of Hyaloscypha, is also transferred to the synonymy of the latter genus. Hyaloscypha melinii is introduced as a new root-symbiotic species from Central Europe. Cadophora finlandica and C. paucisporum are confirmed conspecific, and four new combinations in Hyaloscypha are proposed. Based on phylogenetic analyses, some sexually reproducing species can be attributed to their asexual counterparts for the first time whereas the majority is so far known only in the sexual or asexual state. Hyaloscypha bicolor sporulating in vitro is reported for the first time. Surprisingly, the mycological and mycorrhizal sides of the same coin have never been formally associated, mainly because the sexual and asexual morphs of these fungi have been studied in isolation by different research communities. Evaluating all these aspects allowed us to stabilize the taxonomy of a widespread and ecologically well-studied group of root-associated fungi and to link their various life-styles including saprobes, bryophilous fungi, root endophytes as well as fungi forming ericoid mycorrhizae and ectomycorrhizae.

A plant growth-promoting symbiosis between Mycena galopus and Vaccinium corymbosum seedlings.

Typically, Mycena species are viewed as saprotrophic fungi. However, numerous detections of Mycena spp. in the roots of green plants suggest that a continuum from saprotrophy to biotrophy could exist. In particular, mycenoid species have repeatedly been found in Ericaceae plant roots. Our study asked whether (1) Mycena species are commonly found in the roots of green Ericaceae plants; (2) Mycena sequences are limited to a single group/lineage within the genus; and (3) a Mycena sp. can behave as a beneficial root associate with a typical ericoid mycorrhizal plant (Vaccinium corymbosum), regardless of how much external labile carbon is available. We detected Mycena sequences in roots of all sampled Ericaceae plants. Our Mycena sequences clustered in four different groups distributed across the Mycena genus. Only one group could be assigned with confidence to a named species (M. galopus). Our Mycena sequences clustered with other Mycena sequences detected in roots of ericoid mycorrhizal plant species collected throughout Europe, America, and Australia. An isolate of M. galopus promoted growth of V. corymbosum seedlings in vitro regardless of external carbon supply in the media. Seedlings inoculated with M. galopus grew as well as those inoculated with the ericoid mycorrhizal fungus Rhizoscyphus ericae. Surprisingly, this M. galopus isolate colonized Vaccinium roots and formed distinctive peg-like structures. Our results suggest that Mycena species might operate along a saprotroph-symbiotic continuum with a range of ericoid mycorrhizal plant species. We discuss our results in terms of fungal partner recruitment by Ericaceae plants.

First record of Rhizoscyphus ericae in Southern Hemisphere's Ericaceae.

Ericoid mycorrhiza is arguably the least investigated mycorrhizal type, particularly when related to the number of potential hosts and the ecosystems they inhabit. Little is known about the global distribution of ericoid mycorrhizal (ErM) fungi, and this holds true even for the prominent ErM mycobiont Rhizoscyphus ericae. Earlier studies suggested R. ericae might be low in abundance or absent in the roots of Southern Hemisphere's Ericaceae, and our previous investigations in two Argentine Patagonian forests supported this view. Here, we revisited the formerly investigated area, albeit at a higher altitude, and screened fungi inhabiting hair roots of Gaultheria caespitosa and Gaultheria pumila at a treeless alpine site using the same methods as previously. We obtained 234 isolates, most of them belonging to Ascomycota. In contrast to previous findings, however, among 37 detected operational taxonomic units (OTUs), OTU 1 (=R. ericae s. str.) comprised the highest number of isolates (87, ∼37%). Most of the OTUs and isolates belonged to the Helotiales, and 82.5% of isolates belonged to OTUs shared between both Gaultheria species. At the alpine site, ericoid mycorrhizal fungi dominated, followed by dark septate endophytes and aquatic hyphomycetes probably acting as root endophytes. Our results suggest that the distribution of R. ericae is influenced, among others, by factors related to altitude such as soil type and presence/absence and type of the neighboring vegetation. Our study is the first report on R. ericae colonizing Ericaceae roots in the Southern Hemisphere and extends the known range of this prominent ErM species to NW Patagonia.

Experimental evidence of ericoid mycorrhizal potential within Serendipitaceae (Sebacinales).

The Sebacinales are a monophyletic group of ubiquitous hymenomycetous mycobionts which form ericoid and orchid mycorrhizae, ecto- and ectendomycorrhizae, and nonspecific root endophytic associations with a wide spectrum of plants. However, due to the complete lack of fungal isolates derived from Ericaceae roots, the Sebacinales ericoid mycorrhizal (ErM) potential has not yet been tested experimentally. Here, we report for the first time isolation of a serendipitoid (formerly Sebacinales Group B) mycobiont from Ericaceae which survived in pure culture for several years. This allowed us to test its ability to form ericoid mycorrhizae with an Ericaceae host in vitro, to describe its development and colonization pattern in host roots over time, and to compare its performance with typical ErM fungi and other serendipitoids derived from non-Ericaceae hosts. Out of ten serendipitoid isolates tested, eight intracellularly colonized Vaccinium hair roots, but only the Ericaceae-derived isolate repeatedly formed typical ericoid mycorrhiza morphologically identical to ericoid mycorrhiza commonly found in naturally colonized Ericaceae, but yet different from ericoid mycorrhiza formed in vitro by the prominent ascomycetous ErM fungus Rhizoscyphus ericae. One Orchidaceae-derived isolate repeatedly formed abundant hyaline intracellular microsclerotia morphologically identical to those occasionally found in naturally colonized Ericaceae, and an isolate of Serendipita (= Piriformospora) indica produced abundant intracellular chlamydospores typical of this species. Our results confirm for the first time experimentally that some Sebacinales can form ericoid mycorrhiza, point to their broad endophytic potential in Ericaceae hosts, and suggest possible ericoid mycorrhizal specificity in Serendipitaceae.

Mycorrhizal Formation and Diversity of Endophytic Fungi in Hair Roots of Vaccinium oldhamii Miq. in Japan.

The root diameters as well as colonization and diversity of the root-associating fungi of Vaccinium oldhamii Miq. were investigated in order to obtain information on their mycorrhizal properties. The distal regions of roots had typical hair roots with diameters of less than 100 μm. Ericoid mycorrhizal fungi (ErMF) and dark septate endophytes (DSE) were frequently observed in the roots. Ascomycetes, particularly helotialean fungi, appeared to be dominant among the endophytic fungi of V. oldhamii roots. Furthermore, Rhizoscyphus ericae (Read) Zhuang & Korf and Oidiodendron maius Barron known as ErMF were detected more frequently than other fungal species.

Fungal symbioses in bryophytes: New insights in the Twenty First Century

Fungal symbioses are one of the key attributes of land plants. The twenty first century has witnessed the increasing use of molecular data complemented by cytological studies in understanding the nature of bryophyte-fungal associations and unravelling the early evolution of fungal symbioses at the foot of the land plant tree. Isolation and resynthesis experiments have shed considerable light on host ranges and very recently have produced an incisive insight into functional relationships. Fungi with distinctive cytology embracing short-lived intracellular fungal lumps, intercellular hyphae and thick-walled spores in Treubia and Haplomitrium are currently being identified as belonging to a more ancient group of fungi than the glomeromycetes, previously assumed to be the most primitive fungi forming symbioses with land plants. Glomeromycetes, like those in lower tracheophytes, are widespread in complex and simple thalloid liverworts. Limited molecular identification of these as belonging to the derived clade Glomus Group A has led to the suggestion of host swapping from tracheophytes. Ascomycetes, all identified to date as Rhizoscyphus ericae and having an extremely wide host range extending into the Ericales, occur in the rhizoids of a range of leafy liverwort families that are sister to the Schistochilaceae, where the fungus induces rhizoid branching and septation. Dating of the Schistochilaceae suggests that these liverwort rhizoid associations predated ericoid mycorrhizas. A more restricted distribution of basidiomycetes, all identified as members of the genus Sebacina, is interpreted as a secondary acquisition in leafy liverworts following the loss of ascomycetes. Unlike the latter and ectomycorrhizal basidiomycetes in tracheophytes, these are host specific. Whereas there is no evidence of host digestion for either the ascomycetes or basidiomycetes in leafy liverworts, basidiomycetes in the Aneuraceae display regular colonization and digestion cycles. Considerable molecular diversity in the aneuracean fungi, mainly in the genus Tulasnella with occasional sebacinoids, mirrors the same in the host liverworts. Nesting of the only mycoheterotrophic liverwort Cryptothallus within Aneura is congruent with the phylogeny of the endophytes. Glomeromycete fungi have been identified in Phaeoceros and Anthoceros whereas Dendroceros, Megaceros and Nothoceros lack endophytes but the distribution of fungi across hornworts has yet to be explored. In contrast to liverworts and hornworts, there is no evidence of mycorrhiza-like associations in mosses. Claims that the fossil Prototaxites was a fossil fungus-associated liverwort are discounted.

Is the prominent ericoid mycorrhizal fungus Rhizoscyphus ericae absent in the Southern Hemisphere's Ericaceae? A case study on the diversity of root mycobionts in Gaultheria spp. from northwest Patagonia, Argentina.

Ericaceae diversity hotspots are in the mountains of the Neotropics and Papua New Guinea, South Africa's fynbos and Southeast Asia but majority of references to their root mycobionts come from the Northern Hemisphere. Here, typical cultivable ericoid mycorrhizal (ErM) fungi comprise Rhizoscyphus ericae, Meliniomyces variabilis, and Oidiodendron maius. It is however unclear whether this is true also for the Southern Hemisphere. Our study focused on cultivable mycobionts from hair roots of Gaultheria mucronata and Gaultheria poeppigii (Ericaceae) from two natural forests in NW Patagonia, Argentina, differing in mycorrhizal preferences of their tree dominants. We detected 62 well-defined OTUs mostly belonging to Helotiales and Hypocreales; the most frequent were Phialocephala fortinii s. l., Pochonia suchlasporia, and Ilyonectria radicicola. Only one out of 257 isolates showed ITS nrDNA similarity to members of the R. ericae aggregate (REA) but was not conspecific with R. ericae, and only five isolates were conspecific with O. maius. Microscopic observations showed that the screened roots were frequently colonized in a manner differing from the pattern typically produced by R. ericae and O. maius. A re-synthesis experiment with selected isolates showed that only O. maius formed colonization resembling ericoid mycorrhiza. Amplification of root fungal DNA with REA-specific and Sebacinaceae-specific primers showed that REA mycobionts were present in some of the screened samples while Sebacinaceae were present in all samples. These results suggest that Gaultheria spp. from NW Patagonia form ericoid mycorrhizae predominantly with the difficult-to-cultivate Sebacinaceae while the incidence of REA is relatively low and may be masked by other most likely non-mycorrhizal cultivable mycobionts.

In vitro interactions between ectomycorrhizal fungi and ericaceous plants

In view of the close association between ericaceous shrubs and ectomycorrhizal trees in forest ecosystems, the interaction between ectomycorrhizal basidiomycetes and the hair roots of four typical ericoid mycorrhizal hosts was investigated in vitro. Seedlings of Vaccinium myrtillus, V. vitis-idaea, V. macrocarpon and Calluna vulgaris were inoculated with each of four ectomycorrhizal basidiomycetes from different phylogenetic groups (Laccaria bicolor, Lactarius musteus, Suillus variegatus and Tomentellopsis submollis) in a low carbon and nutrient agar-cellophane culture system. Two ericoid mycorrhizal Helotiales ascomycetes (Meliniomyces bicolor in the Rhizoscyphus ericae aggregate and a mycobiont out of the Rhizoscyphus ericae aggregate) were included for comparison. Interactions between fungi and hair roots ranged from neutral to surface attachment, and the formation of intracellular hyphal coils. Root and shoot responses to inoculation were different between the host/fungus combinations. The ectomycorrhizal fungus L. bicolor formed extensive intracellular colonization, spreading cell-to-cell with multiple hyphal entry points and intracellular hyphal coils with single entry points in C. vulgaris and V. macrocarpon epidermal cells respectively, however, no significant effects on plant growth were detected. Meliniomyces bicolor formed intracellular hyphal coils in the epidermal cells of V. myrtillus and V. macrocarpon but not the other host spp. The M. bicolor isolate stimulate V. myrtillus root length about 2.5 times. Interestingly, although the unknown ascomycete strain out of the Rhizoscyphus ericae aggregate formed intracellular hyphal coils in epidermal cells of all host plants, it suppressed the growth of C. vulgaris, V. myrtillus, and V. vitis-idaea but not to V. macrocarpon. Further and more detailed experimentation under more ecological realistic conditions for a longer period of time is needed.

Ericoid mycorrhizal root fungi and their multicopper oxidases from a temperate forest shrub.

Ericoid mycorrhizal fungi (ERM) may specialize in capturing nutrients from their host's litter as a strategy for regulating nutrient cycles in terrestrial ecosystems. In spite of their potential significance, we know little about the structure of ERM fungal communities and the genetic basis of their saprotrophic traits (e.g., genes encoding extracellular enzymes). Rhododendron maximum is a model ERM understory shrub that influences the nutrient cycles of montane hardwood forests in the southern Appalachians (North Carolina, USA). We sampled ERM roots of R. maximum from organic and mineral soil horizons and identified root fungi by amplifying and sequencing internal transcribed spacer (ITS) ribosomal DNA (rDNA) collected from cultures and clones. We observed 71 fungal taxa on ERM roots, including known symbionts Rhizoscyphus ericae and Oidiodendron maius, putative symbionts from the Helotiales, Chaetothyriales, and Sebacinales, ectomycorrhizal symbionts, and saprotrophs. Supporting the idea that ERM fungi are adept saprotrophs, richness of root-fungi was greater in organic than in mineral soil horizons. To study the genetic diversity of oxidative enzymes that contribute to decomposition, we amplified and sequenced a portion of genes encoding multicopper oxidases (MCOs) from ERM ascomycetes. Most fungi possessed multiple copies of MCO sequences with strong similarities to known ferroxidases and laccases. Our findings indicate that R. maximum associates with a taxonomically and ecologically diverse fungal community. The study of MCO gene diversity and expression may be useful for understanding how ERM root fungi regulate the cycling of nutrients between the host plant and the soil environment.

Community structure of ericoid mycorrhizas and root-associated fungi of Vaccinium membranaceum across an elevation gradient in the Canadian Rocky Mountains

Abstract The ecological plasticity of Vaccinium membranaceum (Ericaceae) to grow from valley bottoms to alpine habitats allowed us to test if fungal community structure varies along an elevation gradient in east-central British Columbia. Using the shrub as an independent variable, and plant and soil features along the gradient to model a changing climate, communities of root-associated fungi were investigated. The colonized roots from 40 individuals were examined using culture-dependent sequencing and ARISA (automated ribosomal intergenic spacer analysis). Our results demonstrated that high elevation fungal communities, characterised by Rhizoscyphus ericae , differ from lower elevation communities, where Phialocephala fortinii was the most frequently isolated fungus. Co-occurrence analysis indicated that, overall, fungi tended to occur together more often than would be expected by chance. At the scale of the individual host plant, facilitation may play a more important role than competition in shaping fungal communities in these ecosystems.

Corrigendum

New PhytologistVolume 189, Issue 2 p. 643-643 Free Access Corrigendum This article corrects the following: New insights into the mycorrhizal Rhizoscyphus ericae aggregate: spatial structure and co-colonization of ectomycorrhizal and ericoid roots Gwen-Aëlle Grelet, David Johnson, Trude Vrålstad, Ian J. Alexander, Ian C. Anderson, Volume 188Issue 1New Phytologist pages: 210-222 First Published online: July 2, 2010 First published: 11 November 2010 https://doi.org/10.1111/j.1469-8137.2010.03560.xCitations: 2AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat New Phytologist 188 (2010), 210–222. Since its publication, the authors of Grelet et al. (2010) have brought to our attention that there are errors in the names of two fungal isolates (GT02P1 and GT03V1) in their paper. The two isolates have now been deposited in the University of Alberta Microfungus collection and herbarium (UAMH) culture collection: GT02P1 is UAMH 11265 = Isolate F = GT02V1; GT03V1 is UAMH 11266 = Isolate Hc = GT03P1. In Table 1 and Fig. 3, GT02P1 should read GT02V1 and GT03V1 should read GT03P1. We apologize to our readers for these mistakes. Reference Grelet G-A, Johnson D, Vrålstad T, Alexander IJ, Anderson IC. 2010. New insights into the mycorrhizal Rhizoscyphus ericae aggregate: spatial structure and co-colonization of ectomycorrhizal and ericoid roots. New Phytologist 188: 210– 222. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar Citing Literature Volume189, Issue2January 2011Pages 643-643 ReferencesRelatedInformation

New insights into the mycorrhizal Rhizoscyphus ericae aggregate: spatial structure and co‐colonization of ectomycorrhizal and ericoid roots

• Fungi in the Rhizoscyphus ericae aggregate have been recovered from the roots of co-occurring ericaceous shrubs and ectomycorrhizal trees. However, to date, there is no evidence that the same individual genotypes colonize both hosts, and no information on the extent of the mycelial networks that might form. • Using spatially explicit core sampling, we isolated fungi from neighbouring Pinus sylvestris (ectomycorrhizal) and Vaccinium vitis-idaea (ericoid mycorrhizal) roots and applied intersimple sequence repeat (ISSR) typing to assess the occurrence and extent of shared genets. • Most isolates were identified as Meliniomyces variabilis, and isolates with identical ISSR profiles were obtained from neighbouring ericoid and ectomycorrhizal roots on a number of occasions. However, genet sizes were small (< 13 cm), and several genets were found in a single soil core. Genetic relatedness was independent of spatial separation at the scales investigated (< 43 m) and M. variabilis populations from sites 20 km apart were genetically indistinguishable. • We conclude that individual genets of M. variabilis can simultaneously colonize Scots pine and Vaccinium roots, but there is no evidence for the formation of large mycelial networks. Our data also suggest significant genotypic overlap between widely separated populations of this ubiquitous root-associated fungus.

Structural changes to a mycothallus along a latitudinal transect through the maritime and sub-Antarctic

Previous studies have shown the leafy liverwort Cephaloziella varians to associate consistently with fungi, typically the ericoid mycorrhizal symbiont Rhizoscyphus ericae, across a wide latitudinal gradient in the maritime and sub-Antarctic. Hitherto, however, there are no quantitative data on the intensity of colonisation of C. varians by fungal structures in the natural environment and how colonisation might vary with changing environmental conditions. A study is hence reported showing that the frequency of colonisation by fungal structures of C. varians alters along a latitudinal transect from South Georgia (54° S, 38° W) to Moutonnée Valley on Alexander Island (71° S, 68° W). The percentage of stem length colonised by dark septate (DS) hyphae increased significantly along the transect, from 30% at South Georgia to 97% at Moutonnée Valley. In contrast, the percentage of stem length colonised by hyaline hyphae decreased significantly, from 85% at South Georgia to 13% at Moutonnée Valley, and that colonised by hyphal coils similarly decreased from 71% at the former location to 15% at the latter. The frequencies of DS hyphae were negatively associated with mean annual and seasonal air temperatures, whereas those of hyaline septate hyphae and hyphal coils were positively associated with air temperatures. Coils at northerly locations were more convoluted than those at southerly locations. The data indicate that hyphal coils, usually associated with nutrient exchange between partners in ericoid mycorrhizas, do form in C. varians tissues in the maritime and sub-Antarctic, but that the frequency of these structures diminishes in colder habitats.

Co-existing ericaceous plant species in a subarctic mire community share fungal root endophytes

Abstract During the last decade, culture-independent identification tools have widened our knowledge of fungi colonizing ericaceous roots including ericoid mycorrhizal fungi. One focal interest has been to identify fungi, which simultaneously can establish ericoid and ectomycorrhiza, while knowledge about the fungal composition in roots of co-existing ericaceous plants is scarce. In the present paper, the fungal community in roots of four ericaceous plant species, Empetrum hermaphroditum, Andromeda polifolia, Vaccinium uliginosum and Vaccinium vitis-idaea which often dominate subarctic heaths and mires, was studied. From each of these plants, in each of five plots, clone libraries were established using fungal specific ITS-PCR followed by cloning, PCR–RFLP and sequencing. The clone libraries were dominated by potential ericoid mycorrhizal fungi, particularly Rhizoscyphus ericae, fungi belonging to the Sebacinales group B, and Capronia-like fungi. Additionally, the results showed that while ericaceous plant species growing within the same 15 × 15 cm blocks shared a common fungal community, plots just 2–3 m away harboured a significantly different fungal community. The possible functional implications of co-existing ericaceous plants being interlinked by a common mycelial network are discussed.

The biology and ecology of the liverwort Cephaloziella varians in Antarctica

AbstractThe biology and ecology of Cephaloziella varians, the most widespread and abundant liverwort in Antarctica, are reviewed. A description of the species is given, together with information on its geographical distribution, reproduction, habitats, associated organisms and responses to environmental stresses. Characteristics of its photosynthetic physiology are also presented, including data on oxygen evolution rates and chlorophyll a fluorescence parameters. Substratum and tissue chemistry, water relations and pigments are discussed, along with recent data demonstrating that the dark pigment in the apical leaves of C. varians is the anthocyanidin riccionidin A. Recent studies showing that the ericoid mycorrhizal symbiont Rhizoscyphus ericae is present in the tissues of the plant at a wide range of locations in the maritime and sub-Antarctic are also described. It is evident, from the literature reviewed, that C. varians has several adaptations that enable it to survive in the Antarctic biome, explaining its survival at higher latitudes than any other hepatic. The species’ major adaptations include the synthesis of riccionidin A in apical leaves, enabling efficient heat absorption and protection from photoinhibition, and the presence in stems and rhizoids of fungal hyphae, which are potentially beneficial to the hepatic’s nutrition and possibly also synthesize cryoprotectants.

No evidence that nitrogen enrichment affect fungal communities of Vaccinium roots in two contrasting boreal forest types

In boreal forests ericaceous shrubs often dominate the forest floor vegetation. Nitrogen enrichment has been shown to decrease shrub abundance and in this study we explored whether it also affects the root associated fungal communities. Fine roots of Vaccinium myrtillus were collected in a Norway spruce dominated forest and of Vaccinium vitis-idaea in a Scots pine dominated forest. In both forests, nitrogen enrichment was experimentally induced by adding 12.5 and 50 kg N ha −1 yr −1 for 12 (spruce forest) and four (pine forest) years. Based on terminal restriction fragment length polymorphisms, subcloning and sequencing analyses, the root associated fungal communities were examined. We found 93 fungal species including Asco-, Basidio- and Zygo-mycota. In general, the Rhizoscyphus ericae aggregate was the most dominant and this was followed by Herpotrichiellaceae and Sebacina. Ordination analysis revealed that nitrogen enrichment did not change species composition of the fungal communities in neither the spruce nor the pine forest, while fungal community structures were clearly discriminated between the dominant shrub species in each forest. Similarly, no fungal species showed a significant response to nitrogen enrichment. Therefore, nitrogen enrichment appears to have no effect on root associated fungi of understorey dwarf shrubs in boreal forests, while it is clear that spruce and pine forests harbor distinctive communities of these fungi.