Rhizopogon Roseolus Research Articles

Improvement of basidiospore germination and mycelial growth of the ectomycorrhizal mushroom Rhizopogon roseolus in axenic conditions

Improvement of basidiospore germination and mycelial growth of the ectomycorrhizal mushroom Rhizopogon roseolus in axenic conditions

Three-dimensional analysis of ectomycorrhizas formed in Pinus thunbergii roots inoculated with Rhizopogon roseolus

Three-dimensional analysis of ectomycorrhizas formed in Pinus thunbergii roots inoculated with Rhizopogon roseolus

Comparison of salt tolerance of ectomycorrhizal mushroom Rhizopogon roseolus in soil and on agar

Comparison of salt tolerance of ectomycorrhizal mushroom Rhizopogon roseolus in soil and on agar

Effects of Lactarius deliciosus and Rhizopogon roseolus ectomycorrhyzal fungi on seeds and seedlings of Scots and stone pines inoculated with Fusarium oxysporum and Fusarium verticillioides

Two isolates of the edible ectomycorrhizal fungi (ECM), Lactarius deliciosus and Rhizopogon roseolus, were tested against Fusarium oxysporum and F. verticillioides, causal agents of damping-off on ...

Biofuel ash addition increases ectomycorrhizal fungal exudation in pure culture

Environmental contextSpreading recycled wood ash in forests may counteract acidification and nutrient losses, but the process may also affect symbiotic fungi in these eco-systems. We show how fungal species react when exposed to ash solutions; for example, by an increased release of organic acids and other compounds. These effects can influence pH and metal availability in forest soils treated with ash. AbstractRecycling of wood ash may counteract acidification and losses of base cations resulting from whole-tree harvesting in boreal forest ecosystems. The effects of ash treatment on growth and exudation of eight ectomycorrhizal fungal species were investigated in this study. Six basidiomycetes and two ascomycetes were grown in liquid pure culture with different levels of ash amendments. Biomass production, pH and the exudation of 17 low-molecular-mass organic acids (LMMOAs), 23 amino acids (AAs) and 9 hydroxamate siderophores (HSs) were recorded after 1, 2 and 4 weeks of incubation. Ash did not affect fungal growth, but resulted in higher exudation of the investigated compounds, in particular LMMOAs. Ash also influenced the composition of the exudates. We measured exudation of LMMOAs and AAs up to millimolar and micromolar concentrations respectively. For example, Rhizopogon roseolus mainly produced oxalic acid, whereas Lactarius rufus and Tomentellopsis submollis produced the highest concentrations of AAs. Ferricrocin, the only HS detected, was exuded at the nanomolar level. Exudation responses were also highly species-dependent, e.g. the ascomycetous isolates that produced the largest biomass released low amounts of exudates compared with the basidiomycetes, and were the only ones producing siderophores. This growth–exudation response to ash is likely a trade-off in carbon allocation whereby the mycorrhizal fungal species invest carbon in either higher biomass production or higher exudation.

The genus Elaphomyces (Ascomycota, Eurotiales): a ribosomal DNA-based phylogeny and revised systematics of European 'deer truffles'.

Elaphomyces ('deer truffles') is one of the most important ectomycorrhizal fungal genera in temperate and subarctic forest ecosystems, but also one of the least documented in public databases. The current systematics are mainly based on macromorphology, and is not significantly different from that proposed by Vittadini (1831). Within the 49 species recognised worldwide, 23 were originally described from Europe and 17 of these were described before the 20th century. Moreover, very recent phylogenetic treatments of the genus are mainly based on a few extra-European species and most common European species are still poorly documented. Based on an extensive taxonomic sampling mainly made in the biogeographically rich Cantabrian area (Spain), complemented with collections from France, Greece, Italy, Norway, Portugal and Sweden, all currently recognized species in Europe have been sequenced at the ITS and 28S of the rDNA. Combined phylogenetic analyses yielded molecular support to sections Elaphomyces and Ceratogaster (here emended), while a third, basal lineage encompasses the sections Malacodermei and Ascoscleroderma as well as the tropical genus Pseudotulostoma. Species limits are discussed and some taxa formerly proposed as genuine species based on morphology and biogeography are re-evaluated as varieties or forms. Spore size and ornamentation, features of the peridial surface, structure of the peridium, and the presence of mycelium patches attached to the peridial surface emerge as the most significant systematic characters. Four new species: E. barrioi, E. quercicola, E. roseolus and E. violaceoniger, one new variety: E. papillatus var. sulphureopallidus, and two new forms: E. granulatus forma pallidosporus and E. anthracinus forma talosporus are introduced, as well as four new combinations in the genus: E. muricatus var. reticulatus, E. muricatus var. variegatus, E. papillatus var. striatosporus and E. morettii var. cantabricus. Lectotypes and epitypes are designated for most recognised species. For systematic purposes, new infrageneric taxa are introduced: E. sect. Ascoscleroderma stat. nov., E. subsect. Sclerodermei stat. nov., E. subsect. Maculati subsect. nov., E. subsect. Muricati subsect. nov., and E. subsect. Papillati subsect. nov. Lastly, E.laevigatus, E. sapidus, E. sulphureopallidus and E. trappei are excluded from the genus and referred to Rhizopogon roseolus, Astraeus sapidus comb. nov., Astraeus hygrometricus and Terfezia trappei comb. nov. (syn.: Terfezia cistophila), respectively.

Efficacy of propidium iodide and FUN-1 stains for assessing viability in basidiospores of Rhizopogon roseolus

ABSTRACTThe use of spores in applications of ectomycorrhizal fungi requires information regarding spore viability and germination, especially in genera such as Rhizopogon with high rates of spore dormancy. The authors developed a protocol to assess spore viability of Rhizopogon roseolus using four vital stains to quantify spore viability and germination and to optimize storage procedures. They showed that propidium iodide is an excellent stain for quantifying nonviable spores. Observing red fluorescent intravacuolar structures following staining with 2-chloro-4-(2,3-dihydro-3-methyl-(benzo-1,3-thiazol-2-yl)-methylidene)-1-phenylquinolinium iodide (FUN-1) can help identify viable spores that are activated. At 6 mo and 1 y, the spores kept in a water suspension survived better than those left within intact, dry gasterocarps. Our work highlights the importance of temperature, nutrients, and vitamins for maturation and germination of spores of R. roseolus during 1 y of storage.

Population genetics and fine-scale genetic structure of Rhizopogon roseolus in the Tottori sand dune

We investigated the population genetics and fine-scale genetic structure of Rhizopogon roseolus. A total of 173 R. roseolus sporocarps were collected from two stands in the Tottori sand dune. We developed and applied five novel polymorphic microsatellite (SSR; simple sequence repeat) markers for sporocarp genotyping. In total, we identified 110 genets, most of which were small in size. Spatial autocorrelation analyses revealed a significantly positive genetic structure in short-distance classes. The inbreeding coefficient value was significant in both stands (FIS = 0.18), while the FST value (FST = 0.020) indicated little genetic differentiation between the two populations. The majority of alleles were distributed in both stands with similar frequencies. These results suggest that short-distance spore dispersal plays a dominant role in generating new genets, and eventually increases the frequency of inbreeding in the Tottori sand dune, whereas rare gene flow between the two stands, possibly associated with spore dispersal by mycophagous animals, could reduce genetic differentiation.

Rhizopogon roseolus basidiospore germination decreases as the fruiting bodies mature and the spore wall becomes more complex

Rhizopogon roseolus (Corda) Th. Fr. is a basidiomycete truffle that is considered edible. Its gleba changes color from white to beige to brown as it matures. Although ultrastructural changes in the spore wall have been linked to the maturation of the fruiting body, little is known regarding the relationship between spore germination success and the ultrastructure of the spore wall. We examined spore germination on agar plates and analyzed the spore wall ultrastructure using transmission electron microscopy (TEM). Fruiting bodies, collected from a pine forest, were classified into three developmental stages based on gleba color, and the germination success was evaluated at each stage. Variability in the spore germination rate was observed between individual fruiting bodies. The peak germination rate was recorded for the spores from the fruiting bodies in the beige glebal stage, and the rate was lower in the brown glebal stage. When spore wall structures were studied using TEM, the spore wall was found to be multilayered upon maturation of the fruiting body. The spores of the beige glebal stage showed three types of spore walls, namely two-layered, three-layered, and four-layered spore walls. On the other hand, the spores of the brown glebal stage showed predominantly four-layered spore walls. These results indicate that spore germination of R. roseolus decreases as the fruiting body matures and the spore wall becomes more complex.

Isolation of halophilic strains induced by ethyl methanesulfonate in Rhizopogon roseolus

Isolation of halophilic strains induced by ethyl methanesulfonate in <i>Rhizopogon roseolus</i>

Phylogenetic and mycogeographical aspects of Lactarius and Rhizopogon associated with Pinus radiata in south-central Chile

Pinus and Eucalyptus, being grown worldwide for timber and paper pulp industry, are depending on ectomycorrhizal fungi during their entire life cycle; especially Pinus is frequently found to be colonized by highly host-specific root mycobionts such as Suillus spp. or Rhizopogon spp. Although compatible fungi are usually not naturally present when the host tree genus is not native in the planted area, as in the case of Southern Chile, adventitious communities of ectomycorrhizal fungal partners with unknown origin are commonly observed along the extensive range of Chilean Pinus radiata plantations. We performed a molecular phylogenetic analysis focused on two taxa of Lactarius sect. Deliciosi and Rhizopogon, two very common but insufficiently studied ectomycorrhizal fungi in plantations of P. radiata in central Chile, in order to clarify both identity and origin of adventitious fungal strains. Based on ITS sequences from different specimens covering a larger distribution area, we identified the examined taxa as Lactarius quieticolor and Rhizopogon roseolus. This is the first record of L. quieticolor for South America and there is some evidence that the geographic origin of the examined strains of both species is in the Eurasian region rather than in North America where their host tree P. radiata is native, which raises the discussion how mycorrhizal partners of different geographical origins meet in an allochthonous area.

A Comparative Fatty Acid Compositional Analysis of Different Wild Species of Mushrooms from Turkey

Mushrooms have been recognized as important food items due to their high nutritional and medicinal value. The present work quantifies and compares the fatty acids composition among eleven mushroom species (Auricularia auricular-judae, Collybia dryophila, Flammulina velutipes, Helvella lacunose, Polyporus squamosus, Rhizopogon roseolus, Russula albonigra, Russula delica, Sparassis crispa, Suillus collinitus and Volvariella gloiocephala) harvested from Turkey. The lipid contents of the mushrooms varied from 0.13% (Auricularia auricula-judae) to 2.90% (Sparassis crispa). A total of 14 fatty acids were identified and quantified by gas chromatography in the selected mushrooms species with linoleic (13.17 to 79.41%), oleic (0.71 to 55.07%) and palmitic (8.95 to 30.84%) acids as the major components in the tested mushrooms species. The amount of total saturated fatty acids (SFAs), total monounsaturated FAs (MUFAs) and total polyunsaturated FAs (PUFAs) ranged from 13.97 to 59.44%, 0.94 to 55.44% and 13.54 to 79.93%, respectively. Moreover, the mushrooms tested can be explored as a rich dietary source of essential fatty acids (13.34-79.76%) for human nutrition.

Ectomycorrhizal fungi in association with Pinus sylvestris seedlings promote soil aggregation and soil water repellency

Research on fungal effects on soil aggregation has been heavily biased towards arbuscular mycorrhiza. Even though ectomycorrhizal fungi are thought to be as important as arbuscular mycorrhizal fungi and saprotrophic fungi in contributing to soil structure, there are few experimental studies on this topic. Here we quantified how nine ectomycorrhizal fungi in association with Pinus sylvestris seedlings affected soil aggregation and soil water repellency (SWR) of a sandy loamy soil. Water-stable aggregates (>0.25 mm diameter) increased by 6–12% when plants were associated with Laccaria bicolor, Laccaria laccata, Lactarius theiogalus, Paxillus involutus and Suillus bovinus. Mean weight diameter (MWD) of soil aggregates also increased, primarily in the 2–4 mm diameter size class. However, Suillus granulatus increased water-stable aggregates but not MWD, conversely Rhizopogon roseolus and Suillus luteus increased MWD but not water-stable aggregates. We also found Lt. theiogalus, R. roseolus and S. luteus promoted SWR. Furthermore, hyphal length was weakly correlated with MWD (R = 0.27, P < 0.05), especially with aggregate mass in the 2–4 mm size class (R = 0.32, P < 0.05). However, we could not identify clear soil effects (soil pH, soil protein content) serving as explanation for either soil aggregation or SWR. Thus, we conclude that interactions between fungi and soil structure are a species-dependent processes based on yet to be characterized fungal traits. Our results have added further evidence from direct experimentation that ectomycorrhizal fungi can contribute to soil aggregation and SWR.

Variability in nucleus number in basidiospore isolates of Rhizopogon roseolus and their ability to form ectomycorrhizas with host pine roots

Rhizopogon roseolus (Corda) Th. M. Fr., known as “shoro” in Japanese, is a hypogeous basidiomycete that is an ectomycorrhizal symbiont of Pinaceae. In this study, we examined the mycelial organization and karyological phase of the primary and secondary mycelia of this mushroom, and evaluated their ability to form ectomycorrhizal association with host pine roots. Variability in nuclear number was recognized in not only basidiospore isolates but also in hybrid strains obtained from crosses between the isolates. Binucleate cells were the most frequently found in both the basidiospore isolates and hybrid strains. PCR-restriction fragment length polymorphism (RFLP) analysis was performed on two basidiospore isolates, a hybrid strain, and a tissue culture isolate from the fruiting body. The RFLP patterns of the two basidiospore isolates differed, although the total calculated size of the fragments for each isolate was close to the expected size. The compatibility RFLP patterns in the hybrid strain and tissue culture isolate were the same and the total calculated size was up to twice that expected. When unisporic isolates were aseptically inoculated onto the roots of P. thunbergii, typical ectomycorrhizas were formed on the root systems. A semi-thin section from the ectomycorrhiza formed by a unisporic isolate showed the presence of mantle layers surrounding the root and Hartig net hyphae, which developed between the epidermal and cortical cells. This is the first study to show that ectomycorrhizas can be formed by basidiospore isolates, in which the mycelial organization was revealed, and which were karyologically characterized as homokaryon by RFLP.

Influence of Zn and Pb on Rhizopogon roseolus mycelium - energy dispersion spectroscopy and cytochemical investigation

Mycelium isolated from fruitbodies of &lt;em&gt;Rhizopogon roseolus&lt;/em&gt;, collected from calamine wastes in Poland, was cultivated on agar media supplemented with Zn or Pb salts. The stimulation of exudate production by the aerial mycelium and the mycelium growing on the surface of the media, accompanied by the change of mycelium pigmentation, was found as a result of Zn application. The presence of Pb resulted mainly in the stimulation of crystalloid production on the surface of mycelium, in direct contact with the medium. Exudate droplets formed on the surface of mycelium cultivated on media with and without the Zn addition, were investigated by means of cytochemical tests (PATAg and Gomori-Swift reaction). In the control media most droplets gave a diffused, positive reaction to both tests. In media supplemented with Zn salts, besides the droplet-like material described in the control also another kind of exudate was observed. It was characterized by the collar showing apositive Gomori-Swift reaction, while the rest of the exudate had an oily appearance and gave a faint or no reaction to both tests. Comparative research by means of scanning electron microscopy accompanied by energy dispersion spectroscopy, was carried out showing the differences in exudate and in mycelia composition as a result of the Zn and Pb presence in the medium.

A genotype dependent-response to cadmium contamination in soil is displayed by Pinus pinaster in symbiosis with different mycorrhizal fungi

Soil contamination with Cd is of primary concern and beneficial soil restoration strategies urge. The aim of this work is to evaluate the response of two different genotypes of Pinus pinaster (wild and selected) to Cd contamination and to assess how inoculation with ectomycorrhizal fungi, Suillus bovinus and Rhizopogon roseolus, influenced each genotype. Seedlings were exposed to soil contaminated at 15 and 30mgCdkg−1. Plant growth, mycorrhizal traits and Cd accumulation in different tissues of the plant were determined at harvest. The fungal community was assessed by denaturing gradient gel electrophoresis. At 15mgCdkg−1S. bovinus increased aboveground development in both genotypes. At 30mgCdkg−1 non-inoculated wild genotype accumulated more Cd in the shoots (1.7-fold) than the selected genotype; inoculation with R. roseolus decreased Cd concentration in the roots of the selected genotype whereas the opposite occurred in the wild genotype. Cd concentration in the root system was the parameter most influenced by the interaction between the three studied variables. The fungal community established was affected by the Cd concentration in the soil. Results show that different genotypes of P. pinaster react differently to Cd exposure depending on the mycorrhizal association. The importance of considering the combination between plant genotype and its symbiotic partners when aiming at the forestation of degraded land is highlighted.

Short Communication. Physiological effects of Rhizopogon Roseolus on Pinus halepensis seedlings

Aim of study: The inoculation of forest seedlings with ectomycorrhizal fungi can improve the morphological and physiological qualities of plants, especially those used for regeneration of arid areas. Rhizopogon roseolus is an ectomycorrhizal fungus (ECM) commonly used for reforestation. In this study, the specific objectives were to know some morphophysiological effects of Rhizopogon Roseolus on Pinus halepensis seedlings under standard nursery conditionsArea of study: ETSI Montes and EUIT Forestal, Madrid.Material and Methods: In nursery, under well watered conditions and peat growing substrates, Aleppo pine seedlings were inoculated with R. roseolus. Five months after the inoculations, we examined the growth, water parameters (osmotic potential at full turgor [Ψπfull], osmotic potential at zero turgor [Ψπ0], and the tissue modulus of elasticity near full turgor [Emax]), mycorrhizal colonization, and concentration and content of macronutrients in the seedlings. Subsequently, a trial was conducted to assess the root growth potential.Main results: The mycorrhization decreased the height and diameter of mycorrhizal seedlings but increased the root weight and root branching. R. roseolus did not cause any significant effect on the regeneration of new roots or on any of the tested hydric parameters, but it did improve N uptake of the seedlings.Research highlights: The mycorrhizal inoculation increased the N uptake. The mycorrhizal inoculation caused opposite effects on some growth parametersKeywords: Osmotic adjustment; elastic adjustment; mineral nutrition; root growth potential; nursery; Rhizopogon roseolus; Pinus halepensis.

Effects of Media Formulation on the Growth and Morphology of Ectomycorrhizae and Their Association with Host Plant

Tricholoma matsutake and Rhizopogon roseolus form ectomycorrhizal (ECM) association with their host plant on natural habitats. The main objective of this study was to test mycelial growth, morphology, and host plant survival both in vitro and in vivo when treated with enriched media. Aseptically germinated seedlings of Pinus densiflora and P. thunbergii were inoculated with the strains of T. matsutake and R. roseolus, respectively. Under in vitro conditions mycelial growth rates performed best on pH 5 and were better on Modified-Melin-Norkrans-(MMN) based medium and Potato Dextrose Agar (PDA); addition of micronutrients and vitamins in MMN mycelial growth rates had 6–27% differences. Without ECM, plant survival rates on standard media were 30% to below 30% and by inclusion of elements they were 50% to 80%. On in vivo, soil containing different media with ECM allowed successful mycorrhizal association and increased seedling survival rates approximately 100%. Our findings confirm that MMN and PDA allowed higher mycelial growth but poor plant survival (&lt;30%); however, enriched media supported 100% plant survival with successful ECM associations. The present method is advantageous in terms of giving objectivity for ECM by employing suitable media for strains and host plant, and making it possible for mass production of ECM-infected seedlings.

Activity of native hydrolytic enzymes and their association with the cell wall of three ectomycorrhizal fungi

The ecological and biogeochemical relevance of hydrolytic enzymes associated with the fungal cell wall has been poorly studied in ectomycorrhizal (ECM) fungi. We used a modified sequential extraction procedure to investigate the activity of various hydrolytic enzymes (β-glucosidase, acid-phosphatase, leucine-aminopeptidase, chitinase, xylanase and glucuronidase) and their association with the cell wall of three ECM fungi (Rhizopogon roseolus, Paxillus involutus and Piloderma croceum). Fungi were grown on C-rich solid medium under three different P concentrations (3.7, 0.37 and 0.037mM). The sequential extraction procedure classifies enzymes as: (a) cytosolic, (b) loosely bound, (c) hydrophobically bound, (d) ionically bound and (e) covalently bound. Results showed that for the same fungus absolute enzymatic activity was affected by P concentration, whilst enzymatic compartmentalization among the cytosol and the cell wall fractions was not. The association of enzymes with the cell wall was fungus- and enzyme-specific. Our data indicate also that enzymes best known for being either extracellular or cytosolic or both, do act in muro as well. The ecological implications of cell wall-bound enzymes and the potential applications and limitations of sequential extractions are further discussed.

Spores of ectomycorrhizal fungi as inoculants for Nothofagus pumilio and exotic conifer seedlings in Patagonia, Argentina: their activity and conservation

Ectomycorrhizal (EM) fungi incorporation in nursery production is necessary for afforestation with exotic tree species and native forests restoration programs. The fact that spore use as EM inocula is inexpensive and effective, makes it an option more realistic than vegetative inoculum production for many regions around the world. To determine spore activity from EM species selected as inoculants for Nothofagus pumilio and exotic conifers planted in Patagonia, two conservation methods were applied (i.e., dried fruit bodies and spore slurries), and their change over time was assessed (over 8–9 months). Spore activity decreased significantly with time for both native and exotic EM species. Conservation methods showed no significant differences for N. pumilio EM species considered together or for exotic conifer EM species. However, spore activity of different EM species behaved differently with conservation method and over time when considered separately. Taxa which better kept spore activity over time were Austropaxillus statuum and Setchelliogaster fragilis for N. pumilio, and Inocybe kauffmanii for exotic conifers. However, considering together fruit body spore density and spore activity, the species Hallingea purpurea and Cortinarius sp. also appeared as suitable for N. pumilio and Rhizopogon roseolus, R. villosulus, Suillus luteus and S. lakei for exotic conifers. Spore density found in EM fungal fructifications were also established in order to estimate fructification weights necessary to apply a reference dose of active spores in inoculation programs.