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Phoretic nematodes associated with two mass-occurring populations of the millipede Parafontaria laminata were examined, focusing on Pristionchus spp. The nematodes that propagated on dissected millipedes were genotyped using the D2-D3 expansion segments of the 28S ribosomal RNA gene. Four Pristionchus spp. were detected: P. degawai, P. laevicollis, P. fukushimae, and P. entomophagus. Of the four, P. degawai dominated and it was isolated from more than 90% of the millipedes examined. The haplotypes of partial sequences of mitochondrial cytochrome oxidase subunit I examined for Pristionchus spp. and P. degawai showed high haplotype diversity.

The order Hymenochaetales of white rot fungi contain some of the most aggressive wood decayers causing tree deaths around the world. Despite their ecological importance and the impact of diseases they cause, little is known about the evolution and transmission patterns of these pathogens. Here, we sequenced and undertook comparative genomics analyses of Hymenochaetales genomes using brown root rot fungus Phellinus noxius, wood-decomposing fungus Phellinus lamaensis, laminated root rot fungus Phellinus sulphurascens, and trunk pathogen Porodaedalea pini. Many gene families of lignin-degrading enzymes were identified from these fungi, reflecting their ability as white rot fungi. Comparing against distant fungi highlighted the expansion of 1,3-beta-glucan synthases in P. noxius, which may account for its fast-growing attribute. We identified 13 linkage groups conserved within Agaricomycetes, suggesting the evolution of stable karyotypes. We determined that P. noxius has a bipolar heterothallic mating system, with unusual highly expanded ~60 kb A locus as a result of accumulating gene transposition. We investigated the population genomics of 60 P. noxius isolates across multiple islands of the Asia Pacific region. Whole-genome sequencing showed this multinucleate species contains abundant poly-allelic single-nucleotide-polymorphisms (SNPs) with atypical allele frequencies. Different patterns of intra-isolate polymorphism reflect mono-/heterokaryotic states which are both prevalent in nature. We have shown two genetically separated lineages with one spanning across many islands despite the geographical barriers. Both populations possess extraordinary genetic diversity and show contrasting evolutionary scenarios. These results provide a framework to further investigate the genetic basis underlying the fitness and virulence of white rot fungi.

After the accident at the Fukushima Dai-ichi Nuclear Power Plant in 2011, high activities of radiocaesium have been reported in wild mushrooms in Japan. Fungi play an important role in the dynamics of radiocaesium in forest ecosystems. We examined the contents of caesium (Cs), rubidium (Rb), and potassium (K) in the mycelium of 15 isolates of ectomycorrhizal (EM) fungi and nine isolates of saprotrophic (SA) fungi in a synthetic medium with either ammonium chloride (NH4Cl) or sodium nitrate (NaNO3), supplemented with 1 ppm caesium chloride and rubidium chloride. The mycelia were harvested after 8 weeks of incubation, and the contents of Cs, Rb, and K were measured by inductively coupled plasma mass spectrometry. The dry weight of the mycelium in the medium with NH4 was significantly higher than that with NO3, although some EM species, Hebeloma, Astraeus, Scleroderma, and Pisolithus, grew well in the medium with NO3. Among SA species, Crucibulum and Cyathus grew in the medium with NO3. The uptakes of Cs, Rb, and K by Suillus, Pisolithus, and Rhizopogon were higher than that in other EM and SA species when they grew on the medium with NH4, while the uptakes of these elements by Astraeus and Scleroderma were higher than those by other species grown on the medium with NO3. The content of Rb was positively correlated with Cs (r = 0.85, p

Trunk rot, caused by Fomitiporia torreyae, is one of the most economically important sap rot diseases on Cryptomeria japonica, especially on a cutting cultivar ‘Sanbu-sugi’. This disease had been reported only from Chiba and Ibaraki prefectures in Japan; however, a similar trunk rot on Japanese cedars was found recently in Kyoto prefecture. We identified the causal agent of the trunk rot on Japanese cedars in Kyoto prefecture, clarified the genotype of ‘Sanbu-sugi’ (sensu stricto) using microsatellite markers, and then investigated the relatedness of these infected cedars with ‘Sanbu-sugi’. The pathogen was identified as F. torreyae by its DNA sequences and morphological characteristics of the fruiting body. The 25 ramets of ‘Sanbu-sugi’ had only one genotype based on eight microsatellite loci. Infected Japanese cedars in Kyoto were comprised of different genotypes and showed no close relatedness to ‘Sanbu-sugi’. This is the first report of trunk rot caused by F. torreyae on cultivars of Japanese ...

Armillaria possesses several intriguing characteristics that have inspired wide interest in understanding phylogenetic relationships within and among species of this genus. Nuclear ribosomal DNA sequence-based analyses of Armillaria provide only limited information for phylogenetic studies among widely divergent taxa. More recent studies have shown that translation elongation factor 1-α (tef1) sequences are highly informative for phylogenetic analysis of Armillaria species within diverse global regions. This study used Neighbor-net and coalescence-based Bayesian analyses to examine phylogenetic relationships of newly determined and existing tef1 sequences derived from diverse Armillaria species from across the Northern Hemisphere, with Southern Hemisphere Armillaria species included for reference. Based on the Bayesian analysis of tef1 sequences, Armillaria species from the Northern Hemisphere are generally contained within the following four superclades, which are named according to the specific epithet of the most frequently cited species within the superclade: (i) Socialis/Tabescens (exannulate) superclade including Eurasian A. ectypa, North American A. socialis (A. tabescens), and Eurasian A. socialis (A. tabescens) clades; (ii) Mellea superclade including undescribed annulate North American Armillaria sp. (Mexico) and four separate clades of A. mellea (Europe and Iran, eastern Asia, and two groups from North America); (iii) Gallica superclade including Armillaria Nag E (Japan), multiple clades of A. gallica (Asia and Europe), A. calvescens (eastern North America), A. cepistipes (North America), A. altimontana (western USA), A. nabsnona (North America and Japan), and at least two A. gallica clades (North America); and (iv) Solidipes/Ostoyae superclade including two A. solidipes/ostoyae clades (North America), A. gemina (eastern USA), A. solidipes/ostoyae (Eurasia), A. cepistipes (Europe and Japan), A. sinapina (North America and Japan), and A. borealis (Eurasia) clade 2. Of note is that A. borealis (Eurasia) clade 1 appears basal to the Solidipes/Ostoyae and Gallica superclades. The Neighbor-net analysis showed similar phylogenetic relationships. This study further demonstrates the utility of tef1 for global phylogenetic studies of Armillaria species and provides critical insights into multiple taxonomic issues that warrant further study.

Tricholoma dulciolens is an ectomycorrhizal basidiomycete that produces “matsutake”-like mushrooms in association with Picea abies in Fennoscandia. The phylogenetic position of T. dulciolens relative to matsutake species is, however, unknown. In the present study, we demonstrated that T. dulciolens is phylogenetically independent from T. matsutake and its allied species. In addition, herbarium specimens identified as T. caligatum from Abies alba forests in Spain were phylogenetically related to but distinct from T. dulciolens. Based on ribosomal internal transcribed spacer DNA sequence data, T. dulciolens appears to exist in North America, as well. This is the first phylogeny of T. dulciolens in Fennoscandia and its related species in southern Europe.

Agrobacterium tumefaciens-mediated transformation (AMT) was successfully applied to mycelia of the 3 economically important mushrooms Hypsizigus marmoreus, Flammulina velutipes, and Grifola frondosa. We used the hygromycin B resistance gene (hph) under the control of the Cryptococcus neoformans actin promoter. Eighty-six resistant strains of H. marmoreus, 4 of F. velutipes, and 2 of G. frondosa were obtained. All transformants were highly resistant to hygromycin B, suggesting that the C. neoformans actin promoter has a potential universal promoter activity in basidiomycetes. Southern analysis revealed random but single integration of the hph gene.

Tricholoma matsutake (S. Ito & S. Imai) Singer and its allied species are referred to as matsutake worldwide and are the most economically important edible mushrooms in Japan. They are widely distributed in the northern hemisphere and established an ectomycorrhizal relationship with conifer and broadleaf trees. To clarify relationships among T. matsutake and its allies, and to delimit phylogenetic species, we analyzed multilocus datasets (ITS, megB1, tef, gpd) with samples that were correctly identified based on morphological characteristics. Phylogenetic analyses clearly identified four major groups: matsutake, T. bakamatsutake, T. fulvocasta- neum and T. caligatum; the latter three species were outside the matsutake group. The haplotype analyses and median-joining haplotype network analyses showed that the matsutake group included four closely related but clearly distinct taxa (T. matsutake, T. anatolicum, Tricholoma sp. from Mexico and T. magnivelare) from different geographical regions; these were considered to be distinct phylogenetic species.

The relationship between the taxa of airborne fungi and the decay risk was investigated. Airborne fungi in 1,000 l of air were trapped on Japanese cedar disks, and incubated in a damp container kept at 26oC. After 16-week incubation, filamentous fungi grown on the disks were isolated and DNA extracted from each isolate was amplified with the primers ITS4/ITS5. The DNA sequences of the amplified products were determined and compared to the sequence data of GenBank to determine the species or genus according to a BLAST search. This search revealed that the isolate consisted of 5 major taxa, namely Bjerkandera sp., Phanerochaete sp. (A), Phanerochaete sp. (B), Polyporales sp. Polyporus arcularius, and 6 minor ones. Statistical analysis revealed that the major taxa were trapped on the disks in similar weather conditions except for Bjerkandera sp., which was trapped at a cooler temperature. The analysis also proved the disks to which Phanerochaete spp. or Polyporales sp. were attached showed higher mass loss. It is concluded that, under these experimental conditions, related species of Phanerochaete sordida play an important role in increasing the decay risk caused by airborne wood-decay fungi.

A taxonomic study based on morphological and phylogenetic characters revealed that the specimens referred to as ‘Polyporus pseudobetulinus’ in Japan actually represent two distinct species, namely, P. pseudobetulinus and P. subvarius. These cam be distinguished by characteristics of the pileus surface, the presence/absence of clamp-connections on generative hyphae, and the shape of the basidiospores. P. subvarius is newly reported from Japan following the original description from China. The phylogenetic positions, detailed descriptions, and illustrations are provided for both species.

Summary The distribution of genets of a root and butt rot pathogen Heterobasidion parviporum was studied in a 68-year-old Abies sachalinensis plantation in Japan. A total of 33 pure cultures of H. parviporum were isolated from diseased Todo fir stumps after clear-felling. Individual genets of the fungus were identified by three different methods: somatic incompatibility test, random amplified polymorphic DNA, and DNA microsatellite analyses. The combined results of the three analyses identified at least eight genets within a 60 × 100 m plot. One genet, consisting of only one isolate, was genetically differentiated from the other genets by all three methods; the other 32 isolates, however, were grouped with minor discrepancies, into seven genetically close genets. The genetic differentiation was lower than that recorded previously in Europe. A single genet infected 1–15 trees in the plot. The longest distance of the two most isolated trees of a single genet was 51 m. The close genetic relationship between genets and their large sizes suggest that basidiospores from restricted sources (just a few fruiting bodies) infected the site before establishment of the present Todo fir stand and that the disease has spread mainly by vegetative growth of the mycelia through root contact. Absence of fruiting bodies of the fungus in the study plot also suggests the greater importance of vegetative growth than spore dispersal for the spread of this fungus.

ナラタケモドキはサクラ類の根株腐朽病菌として近年問題となっている。そこで, 被害林から分離されたナラタケモドキとワタゲナラタケを用いてサクラ苗への接種試験を行った。ナラタケモドキ接種苗4本のうち1本が接種4年後に枯死した。それらすべての接種苗の根系に菌糸束は認められなかったが, 根株の外樹皮, 内樹皮および形成層に菌糸膜が形成され, 枯死苗では地際部の形成層を取り巻いていた。一方, ワタゲナラタケ接種苗は4本すべて枯死しなかった。それらすべての接種苗の根系に多数の菌糸束が絡み付いていたが, 菌糸膜の形成は外樹皮の一部に限られ, 内樹皮と形成層での菌糸膜形成は接種苗1本の細い根数本のみに認められた。接種苗からはそれぞれの接種菌が再分離された。対照苗3本はすべて枯死せず, 菌糸膜や菌糸束の形成も認められなかった。これらの結果から, ナラタケモドキはサクラ苗の内樹皮と形成層に侵入し, さらに枯死させることが明らかになった。

An undetermined Armillaria species was collected on Amami-Oshima, a subtropical island of Japan. The phylogenetic position of the Armillaria sp. was determined using sequences of the elongation factor-1α (EF-1α) gene and the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) of ribosomal DNA (rDNA). The phylogenetic analyses based on EF-1α and ITS sequences showed that this species differs from known Japanese taxa of Armillaria. The sequences of this species and A. novae-zelandiae from Southeast Asia were contained in a strongly supported clade, which was adjacent to a well-supported sister clade containing A. novae-zelandiae from Australia and New Zealand.

Summary Distribution, host preference and pathogenicity of Japanese Armillaria species on conifers were investigated on the basis of field collections of 65 isolates. We identified seven Armillaria species from 19 conifer species including six major Japanese plantation conifers using mating tests and sequences of the translation elongation-1 α gene. Armillaria mellea, Armillaria ostoyae, Armillaria cepistipes and Armillaria sinapina were frequently collected, whereas Armillaria nabsnona, Armillaria tabescens and a biological species Nagasawa’s E were rare. On the basis of host condition when the isolates were collected, A. mellea, A. ostoyae, A. cepistipes and A. tabescens are considered as moderate to aggressive pathogens of conifers in Japan.

Relationships among East Asian, North American and European Laetiporus sulphureus s. lat., a cosmopolitan brown rot species complex, were assessed with phylogenetic analyses and incompatibility tests. Three East Asian taxa, Laetiporus cremeiporus sp. nov., Laetiporus montanus and Laetiporus versisporus, are described and illustrated as well as compared with related taxa from Southeast Asia, North America and Europe. Phylogenetic analyses showed that L. cremeiporus and L. versisporus are clearly distinct species among Laetiporus taxa. The three conifer inhabiting species, Laetiporus conifericola, Laetiporus huroniensis and L. montanus, are closely related to each other. The European population of L. montanus exhibits two sequence variants of the EF1alpha: one is the same as observed in L. sulphureus in Europe and the other is that observed in East Asian population of L. montanus. A key to the known species of Laetiporus in the northern hemisphere is provided.

Sixty-two isolates from basidiocarps of Armillaria spp. were obtained from Hokkaido Island, northern Japan. Six species (Armillaria cepistipes, A. gallica, A. nabsnona, A. ostoyae, A. sinapina, and an undescribed species, “Nag. E”) were identified by pairing tests with known tester strains and one subspecies (Armillaria mellea subsp. nipponica, a non-heterothallic form of A. mellea) was identified by its macro- and micro-morphological characters of the basidiocarps. This is the first case of “Nag. E” being reported from Hokkaido Island.

Polyporus longiporus, belonging to group Polyporellus, is newly reported from Japan in what also constitutes the second report of the species since its original description. This species is characterized by radially elongated pores, smooth and brown to dark brown pileus, and cylindrical and slightly curved basidiospores. Phylogenetic analysis based on the ITS region revealed that P. longiporus forms a terminal, strongly supported clade that is closely related to P. ciliatus. A description and illustrations of the present species and a key to the species of group Polyporellus are provided.

We describe and illustrate three Heterobasidion species distributed in East Asia, based on both dried specimens and cultures. Heterobasidion parviporum, formerly known as H. annosum from Asia, is characterized by effused-reflexed basidiocarps with cuticulate pilei, small round pores, thin context and short tubes in each layer. Examination of the type specimen of Trametes insularis revealed that this is distinct from the East Asian species widely known as “H. insulare”. No prior correct name for this taxon exists, and thus we propose the name H. orientale sp. nov. Heterobasidion orientale is characterized by sessile to effused-reflexed basidiocarps covered by a thin crust, reddish brown pileus with a marginal white zone and regular to labyrinthiform pores. Heterobasidion ecrustosum sp. nov. is characterized by convex basidiocarps frequently covered by a crust only at the base, large regular pores and long tubes. Morphological characters of these three species are compared with other Heterobasidion species. Cultural characters of these three species are also described. All isolates show oedocephaloid conidiophores bearing subglobose to ovoid conidia. Conidia of H. parviporum are smaller than those of the other two species. Descriptions and a key to the known species of Heterobasidion are provided.

ならたけもどき病は, 樹木園, 緑地等の樹木に樹勢衰退を引き起こす重要病害である。ならたけもどき病が発生しているフユザクラ林において, ナラタケモドキの土壌中の分布把握を意図し, 杭捕捉法によるナラタケモドキの検出を試みた。枯死木を含む試験区と枯死木を含まない任意に設置した試験区の計11試験区を設定し, コナラ枝で作製した杭を計615本設置した結果, 9試験区の計86本の杭にナラタケ属菌の根状菌糸束や菌糸膜が認められた。そのうち58本の杭から分離されたナラタケ属菌の種は, 交配試験およびPCR-RFLP解析によりすべてワタゲナラタケと同定された。ナラタケモドキは杭捕捉法により検出されなかった。ワタゲナラタケは根状菌糸束を豊富に形成し, 土壌中の広い範囲に生息していると考えられた。

Summary The occurrence and symptoms of root and butt rot were examined in a 35 × 30 m plot of 68-year-old Todo fir plantation in Hokkaido, Japan. Forty-seven percent of the cut stumps were decayed and 52% of the decayed stumps showed similar decay characteristics with yellowish orange to light brown colouration and expanded pockets in the heartwood. Morphological characteristics of the pure cultures isolated from the decay were similar to the cultures isolated from basidiocarps of Heterobasidion annosum sensu lato, found on fallen logs outside of the research site. Also DNA analysis based on the combined data set of three gene loci (glyceraldehyde 3-phosphate dehydrogenase, heat shock protein 80–1 and elongation factor 1-alpha genes) showed that the isolates from the decay are included in the same clade with the Japanese H. annosum s.l. isolates. They form a subclade to H. parviporum (the European S group of H. annosum s.l.). This is the first report of molecular determination of H. annosum s.l. isolated from root and butt rot in a plantation in Japan.

Tricholoma matsutake is the most commercially important edible mushroom in pine forests in Japan. Tricholoma bakamatsutake and T. fulvocastaneum, species closely related to T. matsutake, occur in Fagaceae forests. We examined ectomycorrhizal (EM) formation by these Tricholoma species by in vitro synthesis among seven strains (two of T. matsutake, four of T. bakamatsutake, one of T. fulvocastaneum) and axenic plants of pine (Pinus densiflora) and oak (Quercus serrata, Q. phillyraeoides). All strains, except for one of T. matsutake, formed EM associations with both pine and oak. Plant growth and mycelial development were differently affected by EM formation depending on the plant-fungus combination.

Trunk rot poses a substantial threat to Sanbu-sugi, one of the most economically important cultivars of Japanese cedar (Cryptomeria japonica). The etiology of this disease, including its main agents, is incompletely known. This trunk rot was attributed to Fomitiporia (Phellinus) hartigii or F. (Phellinus) punctata. Here we phylogenetically analyzed DNA sequences of four markers from a set of strains isolated from trunk-rot symptoms and recovered a single, monophyletic clade, indicating that a single taxon is involved. This clade was identified as Fomitiporia torreyae, a species described from eastern China. This analysis also proved that trunk rot and/or dieback of other conifers and broadleaf trees, including Sawara cypress (Chamaecyparis pisifera), Japanese umbrella pine (Sciadopitys verticillata) and Japanese pear (Pyrus pyrifolia var. culta), were caused by the same species. The phylogenetic approach to Fomitiporia revealed that the F. torreyae clade was closely related to F. bannaensis but clearly distinct from F. punctata, which originally was thought to be the cause of trunk rot in Sanbu-sugi. Fomitiporia torreyae is redescribed on the basis of more than 40 specimens from multiple hosts from Japan and China. Fomitiporia juniperina comb. nov. is proposed.

“Matsutake” mushrooms are formed by several species of Tricholoma sect. Caligata distributed across the northern hemisphere. A phylogenetic analysis of matsutake based on virtually neutral mutations in DNA sequences resolved robust relationships among Tricholoma anatolicum, Tricholoma bakamatsutake, Tricholoma magnivelare, Tricholoma matsutake, and Tricholoma sp. from Mexico (=Tricholoma sp. Mex). However, relationships among these matsutake and other species, such as Tricholoma caligatum and Tricholoma fulvocastaneum, were ambiguous. We, therefore, analyzed genomic copy numbers of σ marY1 , marY1, and marY2N retrotransposons by comparing them with the single-copy mobile DNA megB1 using real-time polymerase chain reaction (PCR) to clarify matsutake phylogeny. We also examined types of megB1-associated domains, composed of a number of poly (A) and poly (T) reminiscent of RNA-derived DNA elements among these species. Both datasets resolved two distinct groups, one composed of T. bakamatsutake, T. fulvocastaneum, and T. caligatum that could have diverged earlier and the other comprising T. magnivelare, Tricholoma sp. Mex, T. anatolicum, and T. matsutake that could have evolved later. In the first group, T. caligatum was the closest to the second group, followed by T. fulvocastaneum and T. bakamatsutake. Within the second group, T. magnivelare was clearly differentiated from the other species. The data suggest that matsutake underwent substantial evolution between the first group, mostly composed of Fagaceae symbionts, and the second group, comprised only of Pinaceae symbionts, but diverged little within each groups. Mobile DNA markers could be useful in resolving difficult phylogenies due to, for example, closely spaced speciation events.

We analyzed the sequences of three DNA regions-the translation elongation factor-1 alpha (EF-1 alpha) gene and the internal transcribed spacer (ITS) and intergenic spacer (IGS) regions of ribosomal DNA-to compare their accuracy in identifying species of Japanese Armillaria. We studied 49 isolates of eight Armillaria species, A. mellea, A. ostoyae, A. nabsnona, A. cepistipes, A. gallica, A. sinapina, A. tabescens and the biological species Nagasawa E (Nag. E). Phylogenetic analyses of the ITS and IGS data helped in identifying A. mellea, A. ostoyae, A. nabsnona, A. tabescens and Nag. E but could not be used to identify A. gallica, A. cepistipes and A. sinapina. Nevertheless our analysis showed that the EF-1 alpha gene was clearly different in the eight examined species. Restriction fragment length polymorphisms (RFLP) of the IGS-1 region could be used to distinguish most species, but the RFLP profiles of some isolates of A. cepistipes and A. sinapina were the same even with four different restriction enzymes. In conclusion, among the techniques examined in this study, analyzing the EF-1 alpha sequence was found to be the most suitable method for identifying different species of Japanese Armillaria.

Relationships were investigated among North American and Japanese isolates of Laetiporus using phylogenetic analysis of ITS sequences and single-spore isolate incompatibility. Single-spore iso- late pairings revealed no significant compatibility between North American and Japanese isolates. ITS analysis revealed 12 clades within the core Laetiporus clade, seven of which are known to occur in North America (including Hawaii and the Caribbean), three in Japan, two in South America, three in Europe and one in South Africa. The identity of L. sulphureus s.s. has yet to be determined and could be either L. ''sulphureus'' (clade C), which appears to be re- stricted to Europe and occurs on angiosperms and gymnospersm, or L. ''sulphureus'' (clade E), which is found in Europe, North America and South America exclusively on angiosperms. Three clades, one from the Caribbean, one from Hawaii and one from South Africa, have yet to be named formally. Of the three Laetiporus species found in Japan two have been named recently (L. cremeiporus and L. montanus) and one has been epitypified (L. versisporus). The single- spore incompatibility and ITS data support recogni- tion of the three Japanese taxa as distinct biological and evolutionary species.

Polyporus accommodates morphologically heterogeneous species and is divided into six infrageneric groups based on macromorphological characters. On the other hand allied genera have macro- and microscopic characters similar to those of Polyporus. The phylogenetic relationships of Polyporus and allied genera were established from sequences of RNA polymerase II second largest subunit (RPB2), nuclear ribosomal large subunit (nucLSU) and mitochondrial ATPase subunit 6 (ATP6). The molecular phylogenetic trees confirmed that Polyporus is a polyphyletic genus and recognized six major clades (1-6) containing species of Polyporus and several allied genera. Among the clades one contained three infrageneric groups of Polyporus and two allied genera, Datronia and Pseudofavolus while one other contained group Polyporellus and Lentinus. Five of the six major clades contained species belonging to a single infrageneric group, Favolus, Melanopus, Polyporellus or Polyporus. This suggests that morphological characters used to define these groups have phylogenetic significance and reveals the need for a taxonomic revision of Polyporus and its allied genera.

The phylogenetic relationships of two Japanese Heterobasidion species, H. annosum sensu lato and an undetermined species, were revealed based on three gene loci, glyceraldehyde 3-phosphate dehydrogenase (gpd), heat shock protein (hsp) and elongation factor 1-alpha (ef). The tree, based on combined data of gpd, hsp and ef, showed that Japanese H. annosum s.l. was close to the European S-group, forming a subclade. The results of this study also provided strong support for the recognition of the undetermined Heterobasidion sp. as a distinct phylogenetic species closely related to H. araucariae.

The life cycle ofJapanese Armillaria mellea was studied with regard to basidiomata formation from monosporous cultures, the nuclear behavior during basidiospore formation and germination, and DNA content per nucleus at different developmental stages. The nuclear behavior during basidiospore for