Positive relationship between wood size and basidiocarp production of polypore fungi in Alnus acuminata forest

Polypores play a major role in wood decomposition. Based on presence/absence of basidiocarps, it has been shown that richness of polypores in forests is strongly affected by the size of logs. However, no study has addressed the relationship between the log size and basidiocarp production. Here, we examined the relationship between log diameter and number of basidiocarps and volume of the fructification (as surrogate of biomass) of the polypore community in Andean Alder forests from Northwest Argentina. We found a positive relationship between log diameter and basidiocarp production in the whole community analysis (fructifications of all species). This pattern was also followed by dominant species (Bjerkandera adusta, Trametes cubensis and T. versicolor) analyzed individually. The relationship was generally higher for volume of fructification than for number of basidiocarps. Through these effects on basidiocarp production, higher log diameter could promote higher sexual spore production and dispersal hence a higher genetic variability and viable populations of wood-decay species.     

FUNGAL GEL TISSUE ONTOGENESIS

Conspicuous gelatinous tissues, consisting of gel and hyphae, occur in fungi in the discomycete subfamilies Ombrophiloideae and Leotioideae and in the basidiomycete order Tremellales. The origin and subsequent development of gelatinous tissues in representative species were investigated. Fungal gels may be selectively stained with the mucin stain, mucicarmine, and metachromatically with toluidine blue. Gel was found to arise in 2 fundamentally different ways, by hyphal disintegration and by direct secretion of mucilage from the protoplasm. With hyphal disintegration a swelling of the hyphal walls may precede the formation of the gel, as occurs in the conidiophores of Coryne cylichnium, or the hyphae may disintegrate directly to form the gel, as occurs in the basidiocarp of Pseudohydnum gelatinosum. Mucilage secretion occurs in the discomycetes Bulgaria inquinans, Coryne cylichnium, Corynella sp., Cudonia lutea, Holwaya leptosperma, Leotia viscosa, Neobulgaria pura, and Neobulgaria sp. Mucilage is secreted directly from the hyphae, except in the imperfect stage of H. leptosperma in which specialized secretory cells occur. Deeply staining material aggregates in the hypha or cell and is then extruded through small pores in the walls. A subsequent change in viscosity occurs and the mucilage becomes gelatinous. If produced in small amounts, the gel ensheaths the hyphae and collects in the interhypbal spaces in a loosely organized tissue, or forms interstitial gel in a compactly organized tissue. If gel is produced in large amounts it will form a continuous gel matrix regardless of the tissue type. Sites of unusually heavy gel production (here termed “gliatopes”) may be formed in either rapidly developing or confined tissue. Both mucilage secretion and hyphal disintegration to form gel occur in the cupulate coremium of the imperfect stage of C. cylichnium.     

Scytinostroma galactinum as a pathogen of woody plants

Scytinostroma galactinum (Fr.)Donk is the fungus commonly known asCorticium galctinum (Fr.)Burt. Although it occurs as a saprobe on woody plants and plant debris, it also has been considered by several authors as an active pathogen that causes a white root and butt or collar rot. During the summer of 1970, it was found near Baltimore and also in Montgomery County, Maryland, under circumstances that seemingly provide additional records of pathogenicity. Several other Maryland records are cited, and many Canadian studies have been reviewed.S. galactinum has a distinctive dextrinoid mycelium, which is characteristic enough to permit a tentative identification even in the absence of other features. Outstanding elements of the basidiocarp are the dextrinoid hyphae and slender gloeocystidia. In culture, dextrinoid fiber hyphae and papillate oil-bearing hyphae with clamp connections are characteristic. These and other features of the basidiocarp and culture serve in the characterization of this fungus, which is economically significant and widely distributed.     

Starting from scratch: Evolution of the lichen thallus in the basidiolichen Dictyonema (Agaricales: Hygrophoraceae)

Phylogenetic studies indicate that the basidiolichen genus Dictyonema s.lat., often thought to represent only a single genus with few species, includes several well-supported genus-level clades, all of which form associations with a unique lineage of obligately lichenized cyanobacteria (Rhizonema). In an attempt to elucidate the evolution and genus- and species-level diversification in Dictyonema s.lat., we generated 68 new sequences of the nuclear large subunit rDNA (nuLSU), the internal transcribed spacer (ITS), and the RNA polymerase II subunit (RPB2), for 29 species-level lineages representing all major clades of Dictyonema s.lat. and most of the species currently known. The multilocus phylogeny obtained via maximum likelihood and Bayesian approaches indicates the presence of five genus-level groups: a basal clade, Cyphellostereum, that is sister to the rest of the species, a paraphyletic grade representing Dictyonema s.str., and three clades representing the genera Acantholichen, Cora, and Corella. To determine the evolutionary transformations of the lichenized thallus in the group, ancestral character state reconstruction was done using six characters (lichenisation, thallus type, cortex type, hyphal sheath and haustorial type, photobiont morphology, and basidiocarp type). Our analysis indicates a progressive development of the lichenized thallus from loosely organized filamentous crusts with separate, cyphelloid basidiocarps in Cyphellostereum, to filamentous crusts with derived hyphal sheath and cyphelloid–stereoid basidiocarps partially incorporated into the lichen thallus in Dictyonema, to squamulose–foliose thalli with corticioid basidiocarps entirely supported by the lichen thallus in Cora. These results indicate a remarkable evolutionary integration of lichenized and reproductive tissues in Dictyonema s.lat., supporting the hypothesis that, at least in this case, lichenized thalli may have evolved from reproductive structures in their nonlichenized ancestors.     

Amylostereum laevigatum associated with the Japanese horntail,Urocerus japonicus

The fungus associated with the Japanese horntail,Urocerus japonicus, in Kochi, Kagawa and Ehime Prefectures was studied. Cultures isolated from the mycangia of 113 adult females of the horntail showed the same cultural characteristics. Four of basidiocarps found on felled logs ofCryptomeria japonica were identifieds asAmylostereum laevigatum based on morphological characteristics. This was the first record ofA. laevigatum from Japan. The cultures isolated from the basidiocarps had the same cultural characteristics as those from the mycangia ofU. japonicus. One mycangial isolate produced basidiocarps on artificially inoculated stem segments ofCr. japonica after a 6-mo incubation and was identified asA. laevigatum. One isolate from the basidiocarps ofA. laevigatum and one from the mycangium ofU. japonicus were artificially inoculated into five trees each ofChamaecyparis obtusa andCr. japonica. The wood of all inoculated trees showed discoloration, with no difference in shape and pattern of discoloration between the two isolates. The inoculated fungi were reisolated from the areas of discoloration in the inoculated trees.     

Mycorrhizal association of isolates from sporocarps and ectomycorrhizas withPinus densiflora seedlings

Thirty-two isolates from sporocarps of 27 species of macromycetes, 43 isolates from ectomycorrhizas ofPinus densiflora (Japanese red pine) and 1 isolate from an ectomycorrhiza ofQuercus myrsinaefolia were tested for the ability to form mycorrhizas withP. densiflora seedlings in glass tubes. Ten isolates from sporocarps ofHebeloma sp.,Laccaria bicolor, Lactarius chrysorrheus, Suillus granulatus, Scleroderma areolatum, Russula mariae andR. nigricans had formed ectomycorrhizas by 8 months after transplantation. Twenty isolates taken from mycorrhizas including ofCenococcum geophilum, R. mariae andR. nigricans formed ectomycorrhizas. The synthesized mycorrhizas were classified based on morphological characteristics such as hyphal arrangement of their fungal sheath, and appearance of cystidia and emanating hyphae. Twenty-one mycorrhizal types were recognized.Contribution No. 122, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

A new species of <Emphasis Type="Italic">Cortinarius</Emphasis> sect. <Emphasis Type="Italic">Orellani</Emphasis> from Japan

Cortinarius breviradicatus sp. nov., found in deciduous forests, is described and illustrated from Niigata, Japan. It is characterized by its medium-sized to large dark brown basidiocarp, acutely conical pileus, and rooting stipe, and by subglobose to broadly ellipsoid basidiospores. In addition, the extracting solution from its basidiocarps exhibits a strong fluorescence around 400–430 nm in ultraviolet radiation (250 nm), which was observed in a species of Cortinarius sect. Orellani. The new species belongs to the section Orellani. The differences between the new taxon and similar species are briefly discussed.     

Sistotrema subconfluens sp. nov. (Cantharellales,Basidiomycota) from Changbaishan Nature Reserve,northeastern China

Sistotrema, typified by S. confluens, is characterized mainly by its urniform basidia mostly with 6–8 sterigmata as well as by a monomitic hyphal system, oil rich hyphae and smooth basidiospores. The species of this genus have various hymenophore configurations and basidiospore shapes. During a field trip in 2011, two specimens with urniform basidia were collected from Changbaishan Nature Reserve, northeastern China. After careful morphological and molecular studies, they are described and illustrated here as a new species, S. subconfluens. The new species shares a terrestrial habit, stipitate basidiocarps and poroid hymenophores with S. confluens, besides urniform basidia. These characters make the two species different from all other species of Sistotrema with resupinate basidiocarps on wood. Sistotrema subconfluens differs from the type by having larger basidiocarps, shorter basidiospores and consistent poroid hymenophores. In phylogeny inferred from nuclear large subunit rDNA, the two species were sister taxa but clearly separated. The difference of internal transcribed spacer sequences between the two species was 3.6%.     

PILAYELLA LITTORALIS F. RUPINCOLA FROM WASHINGTON: THE LIFE HISTORY IN CULTURE1

The life history of Pilayella littoralis f. rupincola from Washington was studied in culture using supplemented natural seawater media and various temperature, photoperiod, and light intensity regimes. Plants in nature exhibited characteristics typical for f. rupincola. Plants in culture, however, did not show the same morphological features, although they had a life history presumed typical for f. rupincola. Successive generations of plants in culture formed only unilocular sporangia. On the basis of morphological characters and the life history, Kylin elevated f. rupincola to species rank. Variation in morphology of both field collected and cultured specimens makes such recognition untenable. It is concluded that the type of life history alone is not adequate justification for the recognition of P. rupincola as a species, but the stability of the life history in various culture environments appears to warrant continued recognition of this taxon as a distinct form of P. littoralis, as originally proposed by J. E. Areschoug.     

Metamorphosis of the Basidiomycota Ustilago maydis: Transformation of yeast-like cells into basidiocarps

Ustilago maydis (DC) Cda., a phytopathogenic Basidiomycota, is the causal agent of corn smut. During its life cycle U. maydis alternates between a yeast-like, haploid nonpathogenic stage, and a filamentous, dikaryotic pathogenic form that invades the plant and induces tumor formation. As all the members of the Subphylum Ustilaginomycotina, U. maydis is unable to form basidiocarps, instead it produces teliospores within the tumors that germinate forming a septate basidium (phragmobasidium). We have now established conditions allowing a completely different developmental program of U. maydis when grown on solid medium containing auxins in dual cultures with maize embryogenic calli. Under these conditions U. maydis forms large hemi-spheroidal structures with all the morphological and structural characteristics of gastroid-type basidiocarps. These basidiocarps are made of three distinct hyphal layers, the most internal of which (hymenium) contains non-septate basidia (holobasidia) from which four basidiospores develop. In basidiocarps meiosis and genetic recombination occur, and meiotic products (basidiospores) segregate in a Mendelian fashion. These results are evidence of sexual cycle completion of an Ustilaginomycotina in vitro, and the demonstration that, besides its quasi-obligate biotrophic pathogenic mode of life, U. maydis possesses the genetic program to form basidiocarps as occurs in saprophytic Basidiomycota species.     

Phenetic investigation of non-nodulating African species ofAcacia (Leguminosae) using morphological and molecular markers

Morphological and RAPD markers were used to assess the relationships among nodulating and non-nodulating species of AfricanAcacia. Non-nodulating species of AfricanAcacia are only found within subg.Aculeiferum sect.Monacanthea. African species of sect.Monacanthea examined were found to form a group distinct from the other African species examined on a morphological and molecular basis. All lack the ability to nodulate, suggesting that non-nodulation may be used as a taxonomic tool. The species of sect.Aculeiferum were separated by RAPD and morphological analysis into two groups depending on whether they were armed with prickles in pairs and/or prickles in threes, or solitary. A third group of species was identified within sect.Acacia: further subdivision of this group was achieved into subsectt.Pluriseriae andUniseriae. The position ofA. albida relative to other AfricanAcacia species was found to be distinct but not totally independent of the genus. The partitioning and distribution of the genetic variability within the genus is further elucidated by the RAPD analysis of populations ofAcacia species. A population analysis ofA. polyacantha demonstrated geographical and site-specific variation.     

Mycelial interactions inSclerotinia sclerotiorum

Mycelial interactions were examined among 35 isolates ofSclerotinia sclerotiorum and two Asian species,Sclerotinia asari and an unnamed, Japanese species. Pairings were scored as compatible when strains merged to form one colony and incompatible when strains grew to form two distinct colonies. Incompatible mycelial pairings resulted in an interaction zone in which a distinct reaction line and abundant aerial mycelium or thin mycelium were observed with some variation among replicates. All pairings of a strain with itself were compatible. Of the 31 strains ofS. sclerotiorum tested, 21 were mycelially incompatible with all others. Among the remaining 10 strains ofS. sclerotiorum, there were four mycelial compatibility groups consisting of two or three strains each. Pairings ofS. asari with all other strains resulted in a unique incompatible reaction, a mycelium-free interaction zone. Two of three strains of the Japanese species were intercompatible, but pairings of each of the three strains with all other strains were incompatible. Microscopically, mycelial interactions in pairings of strains were complex. Anastomosis between paired strains was not always observed. This may be due in part to the conversion of many hyphal tips, in both compatible and incompatible interactions, to sites of microconidiogenesis no longer capable of hyphal fusion. Incompatible pairings were followed by hyphal deterioration in one or both strains; hyphal deterioration was not observed in compatible interactions. Of the 31 strains tested, 4 strains ofS. sclerotiorum produced apothecia. Pairings between single ascospore isolates within each strain were compatible, as were pairings with the parent isolate. Mycelial interactions of single ascospore isolates with other strains were identical to those of the parent isolate, indicating that the parent fruitbody was homozygous for any determinant(s) of mycelial incompatibility. The data from this study suggest that a high level of mycelial incompatibility exists among strains ofS. sclerotiorum, comparable to levels of vegetative incompatibility reported in other ascomycetes, that the extent of mycelial incompatibility indicates that genetic heterogeneity exists within the species, and that mycelial compatibility/incompatibility reactions may be an effective way of categorizing intraspecific heterogeneity.     

Sclerotial formation in Corticium olivascens and other hymenomycetes

Sclerotia ofCorticium olivascens are reported and described for the first time. Examples include sclerotia collected from a stump ofPinus virginiana in Greenbelt, Maryland, and those formed in several cultures originally developed from spores produced by basidiocarps. Among outstanding characteristics of basidiocarps ofC. olivascens are the greenish or olivaceous color of the hymenial surface, constant presence of clamp-connections, development of septate cystidia, and production of nonamyloid but dextrinoid basidiospores. Cultural characteristics are described, and the negative oxidase reaction is noted.C. olivascens is a highly distinctive fungus which requires further taxonomic attention.

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Zusammenfassung Sclerotia vonCorticium olivascens sind das erste Mal mitgeteilt und beschrieben. Beispiele betrifft Sclerotia, die vom Baumstumpf vonPinus virginiana in Greenbelt, Maryland gesammelt worden sind und diejenigen, die sich in mehreren Kulturen, ursprünglich von Sporen der Basidiocarpen entwickelt haben. Unter den besonderen Kennzeichen der Basidiocarpen vonC. olivascens sind die grünliche oder olive Farbe der Hymenialoberfläche, ständiges Vorkommen der Klammerverbindungen, Entwicklung septierter Cystidien und die Produktion von nicht-amyloiden, sondern dextrinoiden Basidiosporen. Kulturkennzeichen sind beschrieben und die negative Oxidasenreaktion ist erwähnt.C. olivascens ist ein hoch distinguierter Pilz, der eine weitere, taxonomische Aufmerksamkeit verlangt.

     

Three new Perenniporia (Polyporales,Basidiomycota) species from China based on morphological and molecular data

Three new Perenniporia species, P. lacerata, P. luteola and P. tianmuensis, are described based on morphological and molecular characters. Perenniporia lacerata is characterized by an annual habit, resupinate and papery basidiocarps with lacerate pores, a dimitic hyphal system with weakly dextrinoid skeletal hyphae, truncate and dextrinoid basidiospores. Perenniporia luteola is distinguished by a perennial habit, resupinate basidiocarps with buff-yellow pore surface, a dimitic hyphal system with dextrinoid skeletal hyphae, non-truncate and dextrinoid basidiospores. Perenniporia tianmuensis differs in its annual habit, pileate basidiocarps, a dimitic hyphal system with strongly dextrinoid skeletal hyphae, non-truncate and dextrinoid basidiospores. Phylogenetic analysis based on ITS and LSU-rDNA regions revealed five clades for 29 species of Perenniporia used in this study. Both morphological and molecular evidence confirmed the placement of three new species in Perenniporia and showed its relationships with similar species in the genus.     

Taxonomic classification of asexual isolates ofPythium ultimum based on cultural characteristics and mitochondrial DNA restriction patterns

Taxonomic characteristics of 8 isolates ofPythium ultimum and 11 isolates ofPythium in the spherical hyphal swelling (HS) group of Van der Platts-Niterink were compared. Isolates in the two groups had identical temperature growth responses and morphological features of hyphal swellings. All isolates were pathogenic on sugar beet. Attempts to cross HS isolates among themselves and with opposite mating types ofP. heterothallicum andP. sylvaticum failed. HS isolates were not induced to form antheridia when paired with isolates ofP. ultimum using a polycarbonate membrane sandwich technique. In single culture, some HS isolates formed low numbers of spherical structures encompassed by swollen hyphal masses resembling antheridia. Comparisons of restriction banding patterns ofHindIII-digested mitochondrial DNA revealed that all but 1 isolate ofP. ultimum were identical; however, the variable isolate shared 80% of the bands in common with the others. Seven of 11 HS isolates had banding patterns identical to the predominantP. ultimum pattern and 1 isolate shared 96% comigrating bands. On the basis of the number of shared characteristics, these isolates appear to beP. ultimum which have lost the ability to reproduce sexually.     

A new species of <Emphasis Type="Italic">Perenniporia</Emphasis> (Polyporales,Basidiomycota) described from southern China based on morphological and molecular characters

A new poroid wood-inhabiting basidiomycete, Perenniporia nanlingensis, collected in Guangdong Province, southern China, is described and illustrated on the basis of three collections. Both the morphology and phylogenetic analysis of rDNA ITS sequences support this new species. Macroscopically, the new species is characterized by an annual growth habit, resupinate basidiocarps with pinkish buff to cinnamon-buff pore surface when dry. Microscopically, it has a trimitic hyphal system, slightly dextrinoid and cyanophilous skeletal and binding hyphae, and its basidiospores are ellipsoid, truncate, strongly dextrinoid and cyanophilous, 9.0–9.8 × 5.0–5.9 μm.     

Taxonomic study of Asian species of poroid Auriculariales

A taxonomic study of poroid Asian species in the Auriculariales was conducted using phylogenetic and morphological methods. Phylogenetic analyses based on the LSU and ITS regions reveal that Elmerina was a polyphyletic genus. Moreover, E. hexagonoides collected from Malaysia and “E. hexagonoides” from Japan formed two distinct clades within a well-supported larger clade with Protomerulius caryae. These taxa comprise a different lineage from the type species of both Protomerulius and Protodaedalea, and we conclude that they are members of the genus Aporpium. The phylogenetic position of E. cladophora (type species of Elmerina) is still unclear, and we retain Aporpium and Protodaedalea as genera distinct from Elmerina. Aporpium strigosum sp. nov. is described to represent Japanese specimens misidentified as E. hexagonoides. Aporpium is characterized by resupinate to sessile basidiocarps, tough-fleshy to leathery context, poroid hymenophore, dimitic hyphal systems with unbranched skeletal hyphae, clavate to pyriform probasidia, and ellipsoid to cylindrical or allantoid basidiospores. Aporpium strigosum is similar to A. hexagonoides, but can be differentiated by the ochraceous to straw-colored basidiocarps, strigose pileus surface with long and stiff hairs, and the larger pores, basidia, and basidiospores.     

Histochemistry and storage of organic compounds during basidiosporogenesis in the ectomycorrhizal fungus <Emphasis Type="Italic">Pisolithus microcarpus</Emphasis>

Knowledge on the distribution and storage of different organic compounds during basidiosporogenesis in P. microcarpus is paramount to a better understanding of basidiospore recalcitrance to germination. The objective of this work was to detect the presence and distribution of phenolics, reducing sugars, starch, glycogen, total polysaccharides, RNA, and proteins during P. microcarpus basidiosporogenesis. Starch and reducing sugars were not detected in the fungal basidiocarps, while other polysaccharides predominated in the extracellular matrix at the base of the basidiocarp containing unconsolidated peridioles. Phenolics were also detected in this region. Glycogen was present inside the hyphae, basidia, and basidiospores and constitutes an important storage compound in the fungal basidiocarps. In mature basidiospores, RNA accumulation occurred at discrete locations in the cytoplasmatic periphery, while polysaccharides and proteins were shown to predominate in the cell wall. The presence of glycogen, RNA, and proteins inside the basidiospores strongly indicates provision for future germination and suggests that other factors may also influence basidiospore recalcitrance.