Suillus Spraguei Research Articles

Spatiotemporal Transformation in the Alkaloid Profile of Pinus Roots in Response to Mycorrhization.

Root alkaloids remain highly unexplored in ectomycorrhizae development studies. By employing ultrahigh mass resolution mass spectrometry imaging techniques, we showed substantial relocation and transformation of piperidine alkaloids in pine root tips in response to Suillus mycorrhization. We imaged, in the time frame of ectomycorrhizae formation, a completely different alkaloid profile in Pinus strobus, where basidiospores of Suillus spraguei induce morphogenesis of symbiotic tissues, than in Pinus taeda, where such interaction fails to induce morphogenesis. On the basis of spatial colocalization studies, we proposed some alternative routes for biosynthesis of these alkaloids that supplement existing literature data.

The Suillus spraguei complex (Suillaceae, Boletales): new taxon, new hosts and amended descriptions

The morphology, ecology, and phylogenetic relationships of specimens of the Suillus spraguei (synonym S. pictus) complex from China were investigated. One species, S. latteri, is new to science. Descriptions of S. phylopictus and S. kwangtungensis are amended. Two new hosts of the S. spraguei complex, Pinus fenzeliana and P. latteri, are uncovered. A key to all known taxa of the complex in the world is also provided.

Two new species in the Suillus spraguei complex from China

ABSTRACTSuillus spraguei, synonym S. pictus, has been reported from eastern North America and eastern Asia associated with Pinus subgenus Strobus. Published phylogenetic analyses of rRNA internal transcribed spacer (ITS) sequence and population genetic studies indicated that S. spraguei as currently circumscribed might contain several geographically distinct species. This study examined this possibility through a multigene analysis of S. spraguei specimens from eastern North America and eastern Asia. These specimens were associated with Pinus strobus, P. koraiensis, P. armandii, and P. kwangtungensis. The multigene analysis included three genomic regions: the genes for translation elongation factor 1α (TEF1) and RNA polymerase II largest subunit (RPB1), and the nuc rRNA segments ITS1-5.8S-ITS2 (ITS) and 28S D1–D2 domains (28S). This study confirms that the S. spraguei complex consists of at least three cryptic species: S. spraguei sensu stricto associated with P. strobus in eastern North America; S. phylopictus associated with multiple species in Pinus subgenus Strobus (5-needle pines) throughout China and Japan; and S. kwangtungensis, currently found only in P. kwangtungensis forests in southeastern China. A third new species from Japan and Korea was suggested based on ITS phylogeny. Morphologically, S. spraguei and S. phylopictus resemble each other, whereas S. kwangtungensis is covered with more floccose scales. The new species add to the knowledge of macrofungal diversity in eastern Asia and highlight the necessity of comparing broadly distributed species complexes using morphological, molecular, and ecological data.

In Vitro Mycorrhization and Morphological Characterization of Xanthoconium affine with Pinus densiflora

In this study, we investigated the culture conditions of four ectomycorrhizal fungi, namely, Amanita spissacea NIFoS 2719, Pisolithus arhizus NIFoS 2784, Suillus spraguei NIFoS 2848, and Xanthoconium affine NIFoS 2716, in solid and liquid culture media. In addition, we attempted to induce in vitro mycorrhization of the fungi with Pinus densiflora. Prior to liquid culture, we determined the optimal culture conditions for each species in solid media. The results revealed that all species examined are capable of growth in potato dextrose agar (PDA), malt extract agar (MEA), and modified Melin-Norkran’s medium (MMN), although their preferred growth media were different. Liquid culture experiments showed that inorganic nitrogen did not enhance the mycelial growth of all four species. Therefore, we used MMNbased liquid inocula to promote the growth of ectomycorrhizal fungi in our symbiosis culture system. Mycorrhization was observed in Xanthoconium affine NIFoS 2716. Morphological analysis revealed that fungi-inoculated roots of P. densiflora form simple and dichotomous lateral roots with dense mycelia. In addition, inoculation with X. affine NIFoS 2716 promoted root and shoot developments.

PLoS Genetics Issue Image | Vol. 12(10) October 2016

Mushroom fruit body of Suillus spraguei emerging amongst a cluster of club mosses (Lycopodium sp.). Suillus species form exclusive ectomycorrhizal associations with roots of the pine family Pinaceae. See Liao et al. Download October's cover page here. Image Credit: Rytas Vilgalys

Little to no genetic structure in the ectomycorrhizal basidiomycete Suillus spraguei (Syn. S. pictus) across parts of the northeastern USA

Population genetic studies of ectomycorrhizal fungi at scales larger than 100km are still relatively rare with highly variable results. In this study, we determined the population genetic structure of the ectomycorrhizal basidiomycete Suillus spraguei over distances up to 600km in northeastern USA forests. S. spraguei associates exclusively with five-needled pines and only with white pine (Pinus strobus) in the eastern USA. We used six microsatellite loci to assess the genetic structure between eight sites sampled in the Adirondack Park of New York and seven sites sampled in other forests of New York, Pennsylvania, and Massachusetts. Except for one site, little to no genetic differentiation was detected in pairwise comparisons of the sites (F ST = 0 to 0.05). Only one site was moderately differentiated from most other sites (F ST = 0.02 to 0.15). The Mantel test showed no significant correlation between genetic and geographic distances (isolation by distance; R (2) = 0.003, P = 0.3). The STRUCTURE analysis also supported the presence of a single cluster (K = 1).

Analysis of genet size and local gene flow in the ectomycorrhizal basidiomycete Suillus spraguei (synonym S. pictus)

Several recent fine-scale genetic structure studies of ectomycorrhizal fungi have reported significant spatial clustering of genets with similar genotypes, supporting locally restricted gene flow. In this study we used genotype data from microsatellite markers and spatial autocorrelation analysis to examine local gene flow in Suillus spraguei at distances up to 2 km. Previously developed microsatellite markers for S. spraguei from Japan were unsuccessful at amplifying DNA isolated from sporocarps found in New York state, and other research suggested that both are disjunct species. Novel microsatellite markers therefore were developed with New York specimens. We identified nine polymorphic microsatellite loci and developed primer sets to amplify these regions. We tested the efficiency of the primer sets on 50 sporocarps collected from a natural Pinus strobus stand. The majority of the markers were in Hardy-Weinberg and linkage equilibrium. The location of all sampled sporocarps was recorded and used along with multilocus genotype data to create a genet map. The distance between sporocarps with the same multilocus genotype was small (≤ 7.65 m) and the majority of sporocarps collected were genetically unique, suggesting frequent spore establishment and sexual recombination on this site. Spatial autocorrelation analysis did not support clustering of similar genotypes, suggesting few restrictions to gene flow within this local population.

Host range and potential distribution of ectomycorrhizal basidiomycete Suillus pictus in Japan

The host range and potential distribution of the ectomycorrhizal basidiomycete Suillus pictus was evaluated using both in vitro inoculation and bait experiments with sterilized pine seedlings. In both experiments, three pines were selected as host, i.e. Pinus parviflora of the subgen. Strobus , and Pinus densiflora and Pinus thunbergii of the subgen. Pinus which are widely distributed in Japan. The inoculation experiment revealed that fine roots of seedlings of all pine species were colonized by S. pictus and formed typical ectomycorrhizas. The bait experiment with intact soil of a P. parviflora forest, which included propagules of S. pictus , clarified that S. pictus could form ectomycorrhizas on the fine roots of P. parviflora seedlings, while it could not form them on the fine roots of P. densiflora and P. thunbergii . In the bait experiment with intact soil of P. densiflora or P. thunbergii forest, ectomycorrhizas of S. pictus were not observed on the fine roots of P. parviflora . These results demonstrate that the fungus has the potential to form ectomycorrhizas with Pinus subgen. Pinus , but in natural conditions it only lives symbiotically with Pinus subgen. Strobus in Japan. The fact that this fungus has ecological host specificity provides useful information to study the bio- and phylogeography of this fungus.

Microsatellite loci from the ectomycorrhizal basidiomycete Suillus pictus associated with the genus Pinus subgenus Strobus

AbstractSeven microsatellite loci were isolated and characterized from ectomycorrhizal basidiomycete Suillus pictus associated with soft pine species (Pinus subgenus Strobus) using a dual‐suppression‐PCR technique. Microsatellite variation was assessed using 38 isolates of S. pictus sampled from three different local populations in Japan. The number of alleles per locus ranged from three to 12 within populations. These microsatellite loci can be used for studying the allelic variation and genetic structure in/among local populations of S. pictus.

Genet distribution of sporocarps and ectomycorrhizas of Suillus pictus in a Japanese white pine plantation

Summary • Spatial distribution and biomass of genets of sporocarps and ectomycorrhizas of Suillus pictus were studied in a plot of 20 × 24 m established in a Pinus pentaphylla var. himekomatsu plantation. • The biomass of S. pictus ectomycorrhizas was evaluated based on morphotypes, and genets were identified based on the inter-simple sequence repeat (ISSR) polymorphism analysis. • Suillus pictus was one of the dominant ectomycorrhizal fungal species in both the sporocarp and ectomycorrhizal communities in the study plot. Four genets were identified from sporocarps and these coincided with those identified from ectomycorrhizas. Sporocarps of each S. pictus genet occurred separately from those of other genets. Spatial distributions of ectomycorrhizas of each genet were wider than those of sporocarps. The largest genet occupied c. 54% of the plot, and the area of each genet differed considerably. • Vegetative growth of mycelia is assumed to play a more important role in the propagation of S. pictus than colonization from spores because expansions of all the four genets ranged from 25 to 30 m and no small genets were found in this plot.

Spatial distribution of sporocarps and the biomass of ectomycorrhizas of Suillus pictus in a Korean pine (Pinus koraiensis) stand

Spatial distribution of sporocarps of Suillus pictus A.H. Smith and Thiers was studied in a plot of 6 × 12m in size established in a stand of Pinus koraiensis Sieb. et Zucc. in Kyoto, Japan for 4 years, and the biomass of mycorrhizas was examined in the last year. S. pictus was dominant in both sporocarp and ectomycorrhizal community in the study plot. The number of S. pictus sporocarps ranged from 0.94 to 1.26m–2 (surface area) in the study plot and did not vary very much during the study period. Sporocarps of S. pictus occurred in clumps and the distributions of clumps were generally random. As the spots of sporocarp occurrence changed gradually from year to year, the distributions of sporocarps that occurred successively in 2-year periods overlapped, especially when analyzed in 9-m2 unit size using the m * –m method. Mycorrhizas of S. pictus were distributed in more subplots than its sporocarps. Distribution of mycorrhizas and sporocarps of S. pictus generally overlapped well. The biomass of mycorrhizas and mycelia in the mycorrhizas of S. pictus was estimated at 15.5g–2 and 6.2g–2 (surface area) in this plot, respectively. The biomass of mycorrhizas and mycelia in the mycorrhizas supporting the production of one sporocarp (average dry weight was 0.86g) of S. pictus was evaluated as about 16.4 and 7.3gDW, respectively, in this plot.

Assessing biogeographic relationships between North American and Chinese macrofungi

AimA close biogeographic relationship between the macrofungi of eastern North America and eastern Asia has been documented based on comparisons of species lists. In addition to having a similar species composition, the two regions are reported to share a number of species with putative disjunct distributions. This close biogeographic relationship, however, has rarely been tested within a phylogenetic context. In this paper we examine relationships within three genera, Armillaria, Xerula and Suillus (Fungi, Basidiomycetes, Agaricales) chosen as exemplars of different ecological guilds occupied by macrofungi (plant pathogens, saprobes, mutualists).LocationFieldwork for this project centered in eastern North America, Central America, China and Australasia. Material from additional localities were obtained from cooperating herbaria and additional sequences were downloaded from GenBank.MethodsITS sequence data were used to construct phylogenies for each genus.ResultsOnly one of four tested putative disjunct species, Xerula hispida Halling and Mueller, was supported. Material referable to X. furfuracea (Peck) Redhead, Ginns and Shoemaker from China and North America do not form a monophyletic group. Disjunct populations of Suillus spraguei (Berkeley & Curtis) Kuntze were shown to be paraphyletic. The morphological similarity of the Chinese material to the North American material is likely due to morphological stasis. Finally, morphologically identical material referable to Suillus americanus (Peck) Snell in Slipp and Snell from eastern North America and S. sibiricus (Singer) Singer from China, along with the morphologically similar western North American S. sibiricus, probably represent a single circumboreal taxon.Main conclusionsThe resulting data, while not refuting the hypothesis that there exists a relatively close biogeographic relationship for macrofungi between eastern North America and eastern Asia, suggest that the relationship may not be as close as indicated by morphological data. These results are similar to emerging data from analyses of flowering plants displaying putative eastern North American/eastern Asian disjunct distribution patterns.

Effect of copper on tyrosinase activity and polyamine content of some ectomycorrhizal fungi

Several species of ectomycorrhizal fungi were grown on solid and liquid media in order to compare their tyrosinases and polyamine contents in the presence of copper (Cu) stress. Fungi with naturally brown pigmented hyphae ( Pisolithus tinctorius and Boletinellus merulioides ) yielded measurable extracellular tyrosinase at both 0 and 60 μg ml −1 Cu. Of fungi which develop brown pigmentation in response to Cu stress ( Suillus pictus and Suillus granulatus ), only S. pictus produced the enzyme and then only at 60 μg ml −1 Cu. Fungi with other than brown hyphae ( Piloderma bicolor and Cenococcum graniforme ) did not produce extracellular tyrosinase. Intracellular tyrosinase of P. tinctorius and S. granulatus increased in activity due to Cu stress but substrate affinity ( K m ) remained similar. This indicates an increase in the amount of enzyme synthesized and suggests that tyrosine may act in detoxification by irreversibly binding Cu ions. Tyrosinase from control cultures of P. tinctorius had a greater substrate affinity than that from cultures of S. granulatus . Addition of the polyamines putrescine and spermidine to the reaction mixture from P. tinctorius activated and repressed tyrosinase, respectively. Polyamine content of P. tinctorius and B. merulioides was not altered by Cu stress, while that of the two Suillus species was decreased by the addition of Cu to the growth medium. The decrease in fungal polyamine content indicates a change in permeability of the cells both to Cu and to the extracellular signals for polyamine biosynthesis. Our results show that there are probably fundamental differences between stress induced and natural hyphal pigmentation.

Morphology and possible mycobiont (Suillus pictus) of a tuberculate ectomycorrhiza on Pinus strobus

Suillus pictus was consistently associated with tuberculate ectomycorrhizae (tubercles) on Pinus strobus in North Carolina. Histological, cultural, and chemical reaction studies were used to examine this association. Tubercles were examined by light and scanning electron microscopy. Clamp connections, a reduced to absent tannin layer, and appressed mantle hyphae were observed. Naturally occurring rhizomorphs of Suillus pictus and tubercles have a similar morphology consisting of an outer pseudoparenchymatous sheath, large vessel-like cells, and a prosenchymatous layer between the sheath and the vessel-like cells. Similar macroscopic chemical color reactions to 10% FeSO4, 15% KOH, concentrated NH4OH, concentrated H2SO4, and Melzer's reagents were observed on rhizomorphs of S. pictus and tubercles, surface of tubercles, and stipes of S. pictus. Chemical color reactions and growth characteristics of S. pictus and the tubercle mycobiont were similar on different agar media.

In VitroSynthesis of Mycorrhizae Between Presumed Specific and NonspecificPinus+SuillusCombinations

Mycorrhizal synthesis was successful between Pinus resinosa and Suillus americanus, S. brevipes (two isolates), S. luteus, and S. neoalbidipes, and between Pinus strobus and Suillus americanus, S. brevipes (two isolates), S. granulatus, S. pictus, and S. punctipes. Mycorrhizae formed by all combinations were similar in that all had multiple dichotomous branches, hyphae and hyphal strands with microscopic, pigmented, surface incrustations surrounding the mycorrhizae and roots, and in the mantle organization. Mycorrhizae differed in the macroscopic color ofthe mantle and surrounding hyphae and hyphal strands, the amount of hyphal surface incrustation present, the organization of individual hyphae in the mantle layers, the width ofthe mantle, the presence of clamp connections, and the amount of radial elongation of cortical cells. Data on additional diagnostic characters must be collected and evaluated for value in the identification of mycobionts of field-collected mycorrhizae. Numerous reports of putative mycorrhizal associations exist in the literature. Evidence for many of these reports is restricted to field observations of fungusplant occurrences or less frequently by tracing hyphae from the base of sporomata to adjoining plant roots. A more recent trend has been to confirm field observations experimentally by use of in vitro mycorrhizal syntheses. In vitro mycorrhizal synthesis studies provide the most direct and scientifically rigorous means of determining the ability of a fungal isolate to form mycorrhizae while providing much needed anatomical and morphological data on selected plant + fungus com? binations produced under controlled conditions. Morphology and anatomy, combined with other distinctive characters, provide essential data for identifying mycobionts from field collections. Assessment of ability to form mycorrhizae in vitro should provide a basis for furthering our understanding of the complexities of the mycorrhizal relationship, including the apparent specificity exhibited by some mycobionts or its absence in others in nature. The objectives of this study were to assess the ability of seven Minnesotacollected Suillus spp. to form mycorrhizae in vitro with either Pinus resinosa Ait. or Pinus strobus L., or both, and to characterize the resultant mycorrhizae. Suillus americanus (Pk.) Snell in Slipp & Snell, two isolates of Suillus brevipes (Pk.) Kuntze, Suillus luteus (L.: Fr.) S. F. Gray, Suillus neoalbidipes Palm & Stewart, and Suillus punctipes (Pk.) Sing. were paired with P. resinosa; S. americanus, two isolates of S. brevipes, Suillus granulatus (L.:Fr.) Kuntze, Suillus pictus (Pk.) Smith & Thiers, and S. punctipes were paired with P. strobus.