Didymella fagi sp. nov. and its anamorphAscochyta fagi, causing the yellow leaf spot disease ofFagus crenata andQuercus mongolica var.grosseserrata in Japan

AnAscochyta fungus was obtained during a survey of leaf spot diseases ofFagus crenata in the mountains of Aomori prefecture in 1995. The pathogenicity of the fungus toF. crenata was confirmed by inoculation. Its teleomorph was first found on artificially infected leaves after the leaves were placed in an incubator at 5°C with a 12-h photoperiod (approximately 500lx, daylight strip lamps) for 4 mo. The fungus was found to be the causal agent of yellow leaf spots ofF. crenata andQuercus mongolica var.grosseserrata in the field. Comparison with similar fungi so far described from Fagaceae indicated that the anamorph isAscochyta fagi and the teleomorph is an undescribed species ofDidymella. The nameDidymella fagi is introduced for the teleomorph. Correlation between the two morphs has been proved by cultural, morphological and pathological studies.     

Mycosphaerella chaenomelis sp. nov.: The teleomorph ofCercosporella sp., the causal fungus of frosty mildew inChaenomeles sinensis, and its role as the primary infection source

A leaf spot disease called frosty mildew was observed onChaenomeles sinensis throughout Japan. Small brown spots with white tufts occurred followed by successive defoliation. On the fallen leaves, minute black dots are formed. The causal fungus was regarded as a new species ofMycosphaerella, M. chaenomelis, andCercosporella chaenomelis in anamorph. Pathogenicity of the fungus was confirmed only inC. sinensis by inoculation experiments. Colonies of the fungus grew well on potato sucrose agar, and grew at 10–30°C with an optimum temperature of 25°C. The fungus overwintered on the fallen diseased leaves in the form of pseudothecia, and ascospores served as the primary infection source from April to June.     

Extensive host range of an endophytic fungus, <Emphasis Type="Italic">Guignardia endophyllicola</Emphasis> (anamorph: <Emphasis Type="Italic">Phyllosticta capitalensis</Emphasis>)

Isolation of endophytic species of Guignardia (anamorph: Phyllosticta) from healthy leaves of 94 plants (91 species and 3 varieties) in 69 genera, 42 families, was carried out in a test site (Kyoto Herbal Garden) to investigate the host range of Guignardia endophyllicola (anamorph: Phyllosticta capitalensis). Species of Guignardia and Phyllosticta were isolated from the leaves of 67 plants (66 species and 1 variety) belonging to 54 genera, 38 families. Among them, 53 isolates from different plants belonging to 43 genera in 36 families were similar in morphology, and sequence analysis of internal transcribed spacer (ITS) regions of ribosome DNA revealed these isolates to be conspecific with G. endophyllicola. In addition, this fungus was isolated from leaves of various plants collected in different places in Japan and Thailand. Thus, this endophytic fungus has been revealed to live within various vascular plants, angiosperms, gymnosperms, and pteridophytes.     

A new fungal genus, Teracosphaeria, with a phialophora-like anamorph (Sordariomycetes, Ascomycota)

The new genus and species Teracosphaeria petroica is described for a perithecial ascomycete and its anamorph occurring on decayed wood collected in New Zealand. The fungus produces immersed, non-stromatic ceratosphaeria-like perithecia in nature, with hyaline, septate ascospores produced in unitunicate, non-amyloid asci. The anamorph produced in vitro is phialophora-like with lightly pigmented phialides terminating in flaring, deep collarettes that are often noticeably brown with conspicuous periclinal thickening. Phylogenetic analysis of LSU rDNA sequence data indicates that this fungus is distinct from morphologically similar fungi classified in the Chaetosphaeriales, the Trichosphaeriales or the Magnaporthaceae. It forms a monophyletic group with recently described, chaetosphaeria-like ascomycetes, such as the pyrenomycete genus Mirannulata, and shows affinity with the anamorphic species Dictyochaeta cylindrospora. The usefulness of describing anamorph genera for morphologically reduced anamorphs, when anamorph characteristics are actually part of the holomorph diagnosis, is discussed. An apparently contradictory example of the so-called Cordana and Pseudobotrytis anamorphs of Porosphaerella spp. is also discussed.     

Sawadaea nankinensis comb. nov.: a powdery mildew fungus of Acer buergerianum

The anamorphic state of a powdery mildew on trident maple (Acer buergerianum, Aceraceae), belonging to Sawadaea, has been observed since 1980 in Tokyo and other areas of Japan. Since the autumn of 2003, this fungus has begun to produce chasmothecia in various areas of Japan, which were consistent with Erysiphe nankinensis (= Uncinula nankinensis), but apparently contradictory to the characteristics of the anamorph. Based on a molecular phylogenetic analysis using DNA separately extracted from the anamorph and teleomorph of the fungus on A. buergerianum, it could be demonstrated that sequences of this fungus are sister to Sawadaea. As the anamorph belongs to Oidium subgen. Octagoidium and because of the phylogenetic position within the Sawadaea clade, the new combination Sawadaea nankinensis is proposed for this species. The genus Sawadaea is emended to comprise species with consistently unbranched appendages.     

Measuring summer patterns of ascospore release by saltmarsh fungi

One potentially important type of flux from standing-decaying marshgrass is the production and release of ascospores. The most extensive measurements of ascospore release from the principal marshgrass (Spartina alterniflora, smooth cordgrass) of saltmarshes of the eastern coastal United States involved an arbitrary, weeklong period of wet incubation of leaf-blade samples. We examined the possibility that shorter incubations would yield higher estimates of hourly rates of ascospore release, testing wet incubations of 3 to 71 h, using standing-decaying leaf blades of smooth cordgrass from low on living shoots and high on dead shoots. Incubations of 31 h appeared to be optimal. Species compositions of ascospores expelled from the two leaf types were distinctly different: high leaves yielded primarily aMycosphaerella species orPhaeosphaeria halima; low leaves yielded primarilyPhaeosphaeria spartinicola or theMycosphaerella species. All of these species consistently exhibited high coefficients of variation (>100%) for their mean rates of release of ascospores. Only theMycosphaerella species on high leaves gave evidence of a delayed onset of ascospore expulsion during incubation, and this evidence was equivocal. Grand mean rates of ascospore release forP. spartinicola and theMycosphaerella species were, respectively, 106 and 238 spores cm⁻² abaxial leaf area h⁻¹.     

Surculiseries rugispora gen. et sp. nov., a new endophytic mitosporic fungus from leaves ofBruguiera gymnorrhiza

Surculiseries rugispora gen. et sp. nov. is described as an endophytic fungus from leaves ofBruguiera gymnorrhiza in mangrove forests in the Iriomote Is., Okinawa, Japan. This fungus develops peculiar conditiongenous cells that resemble octopus legs with obvious sucker-like scars, and produces lentiform conidia with lines on surface. Sequence analysis of 18S rDNA places this new fungus in the family Xylariaceae and shows its close affinity to the genusAscotricha (anamorph:Dicyma).     

Co-occurrence of Pseudocercospora species and rhytismatalean ascomycetes on maple and camellia in Taiwan

A new species of Pseudocercospora on leaves of Acer albopurpurascens, a maple endemic to Taiwan, is described. The fungus sporulated on leaf spots caused by Vladracula annuliformis (Rhytismatales). Pseudocercospora camelliicola and Coccomyces sinensis on leaves of Camellia cultivars are recorded for the first time for Taiwan and described and illustrated in detail. In contrast to the situation on maple, both fungal species on camellia caused conspicuous breakage of the epidermis during sporulation, which is discussed in connection with fungal succession during leaf litter decomposition.     

Addition and reexamination of Japanese species belonging to the genus <Emphasis Type="Italic">Cercospora</Emphasis> and allied genera. VII. Newly recorded species from Japan (2)

In the seventh report of the present series, four species of the genus Pseudocercospora were added to the Japanese mycoflora. They are Pseudocercospora catappae, P. mali, P. polysciatis-pinnatae, and P. puderi.     

Ophiostoma arduennense sp. nov. (Ophiostomatales, Ascomycota) from Fagus sylvatica in southern Belgium

Ophiostoma arduennense sp. nov. is described from several cultures isolated from Fagus sylvatica in southern Belgium. The species is mainly characterized by globose perithecia with small button-like bases ornamented with brown hyphal hairs of variable length and, long cylindrical necks ending in ostiolate hyphae. It is homothallic with small reniform ascospores and no apparent anamorph. It is closely associated with the ambrosia beetles Xyloterus domesticus and X. signatus. Its phylogenetic relationships within Ophiostoma are discussed and the species is compared with other Ophiostoma species associated with European beech or other broad-leaved trees in Europe, especially species of the O. quercus–O. piceae complex. The species is responsible for a dark brown staining of the sapwood and its role in the decline of beech in Southern Belgium is also discussed.     

Stromatinia cryptomeriae sp. nov., the teleomorph ofGloeosporidina cryptomeriae causing twig blight of Japanese cedar

A new species,Stromatinia cryptomeriae, is described based on a specimen collected in Iwate Prefecture, Japan. It was found on fallen dead branches and twigs of Japanese cedar,Cryptomeria japonica. The morphology of isolates on potato-dextrose agar (PDA), which were obtained from single ascospores ofS. cryptomeriae, was identical withGloeosporidina cryptomeriae, the causal fungus of Japanese cedar twig blight. In an inoculation test using single ascospore isolates, many minute black spots (sclerotioid bodies; sclerotules) and acervuli ofG. cryptomeriae were formed on the necrotic lesions, which developed into typical symptoms of Japanese cedar twig blight. These results show thatStromatinia cryptomeriae is the teleomorph ofG. cryptomeriae. On PDA, the fungus grew over a range of about 1 to 25°C, with the optimum growth at about 15–20°C.     

A phylogenetic study of some <Emphasis Type="Italic">Septoria</Emphasis> species pathogenic to Asteraceae based on ITS ribosomal DNA sequences

The phylogenetic relationships of the following 14 Septoria species pathogenic to Asteraceae were inferred from sequence analyses of the 5.8 S gene of nuclear rDNA and flanking internal transcribed spacers: Septoria atropurpurea, S. astericola, S. calendulae, S. erigerontis, S. gerberae, S. helianthi, S. helianthicola, S. lactucae, S. leucanthemi, S. obesa, S. schnabliana, S. senecionis, S. socia, and S. taraxaci. Fifteen additional Septoria species originating from other host families, eight of which have a known Mycosphaerella teleomorph, were included in the alignment. Also included were selected strains of Cercospora, Pseudocercospora (including Paracercospora), Ramularia, and several other anamorph genera linked to Mycosphaerella available from previous studies. The analyses indicate that the Septoria species from Asteraceae are all closely related, and share an evolutionary history within the Mycosphaerellaceae, grouping amongst miscellaneous Mycosphaerella species, Cercospora and Pseudocercospora spp. Septoria socia is relatively distant from the other Septoria on Asteraceae, and the data suggest that it is more closely related to the maple pathogen S. aceris (tel. M. latebrosa) and poplar pathogen S. populicola (tel. M. populicola). Differences in the ITS sequences indicate that S. socia and S. leucanthemi, which have very similar phenotypes and have been considered to be conspecific in the past, are specifically distinct.     

Aecidium dispori is the aecial anamorph ofPuccinia albispora, sp. nov. (Uredinales)

Aecidium dispori forms spermogonium and aecium onDisporum sessile andD. smilacinum, which are distributed in East Asia. TheAecidium species is found to be an aecial anamorph of aPuccinia fungus, with its uredinial-telial stage being formed onCarex conica, C. dolichostachya subsp.multifolia, C. pisiformis subsp.alterniflora andC. rugata. Urediniospores of this fungus are large, colorless, thick-walled with 4–5 equatorial germ pores. The morphological characteristics of urediniospores and the spermogonial-aecial host do not fit to any set of circumscribing characters of previously described species. We consider the fungus to be a new species and propose a new name,Puccinia albispora, for the fungus.     

Mycopappus quercus sp. nov., causing frosty mildew inQuercus acutissima

The causal fungus of frosty mildew inQuercus acutissima was taxonomically studied. Brown spots with conical white to yellowish tufts of the causal, fungus developed on the leaves, followed by successive defoliation. The fungus was regarded as a new species ofMycopappus, M. quercus, from the morphology of the multicellular propagules. The ascogenous stage and true conidia of the fungus were not observed, although sclerotia were formed on the fallen diseased leaves.     

Addition and reexamination of Japanese species belonging to the genusCercospora and allied genera III Species described by Japanese mycologists (2)

In the third report of the present series, five species ofCercospora sensu lato described by Japanese mycologists were transferred to the genusPseudocercospora after detailed reexamination. They arePseudocercospora photiniae, P. phrymae, P. stephanandrae, P. vaccini andP. kirishimensis. Pseudocercospora photiniae was retained as an independent species, not regarded as a synonym ofP. eriobotryae.     

Molecular phylogenetic and morphological analyses of Oidium heveae, a powdery mildew of rubber tree

Powdery mildew of rubber tree caused by Oidium heveae is an important disease of rubber plantations worldwide. Identification and classification of this fungus is still uncertain because there is no authoritative report of its morphology and no record of its teleomorphic stage. In this study, we compared five specimens of the rubber powdery mildew fungus collected in Malaysia, Thailand, and Brazil based on morphological and molecular characteristics. Morphological results showed that the fungus on rubber tree belongs to Oidium subgen. Pseudoidium. Nucleotide sequence analysis of the ribosomal DNA internal transcribed spacer (ITS) region and the large subunit rRNA gene (28S rDNA) were conducted to determine the relationships of the rubber powdery mildew fungus and to link this anamorphic fungus with its allied teleomorph. The results showed that the rDNA sequences of the two specimens from Malaysia were identical to a specimen from Thailand, whereas they differed by three bases from the two Brazilian isolates: one nucleotide position in the ITS2 and two positions in the 28S sequences. The ITS sequences of the two Brazilian isolates were identical to sequences of Erysiphe sp. on Quercus phillyraeoides collected in Japan, although the 28S sequences differed at one base from sequences of this fungus. Phylogenetic trees of both rDNA regions constructed by the distance and parsimony methods showed that the rubber powdery mildew fungus grouped with Erysiphe sp. on Q. phillyraeoides with 100% bootstrap support. Comparisons of the anamorph of two isolates of Erysiphe sp. from Q. phillyraeoides with the rubber mildew did not reveal any obvious differences between the two powdery mildew taxa, which suggests that O. heveae may be an anamorph of Erysiphe sp. on Q. phillyraeoides. Cross-inoculation tests are required to substantiate this conclusion.     

Small-scale variation in chemical property within logs of Japanese beech in relation to spatial distribution and decay ability of fungi

Fungal communities within a naturally fallen bough of Japanese beech (Fagus crenata) were investigated with reference to chemical properties of decay columns. Five logs were cut out from the fallen bough, which ranged from 10.7 to 20.5 cm in diameter. Nine fungal species and one sterile fungus were isolated from decay columns that elongated along a longitudinal axis and were delimited by black zone lines and wood discoloration. Lampteromyces japonicus and Trichoderma spp. were isolated from all five logs. Lampteromyces japonicus and Antrodiella albocinnamomea occupied the largest volume in the logs. Lignin and carbohydrate contents, lignocellulose index (LCI), nitrogen content, and water content were different among decay columns colonized by different fungal species in each log. In L. japonicus, LCI of decay column was correlated to that of wood blocks decayed under pure culture condition by the fungi isolated from the decay columns. These results suggest that the small-scale variation in chemical properties within fallen logs of Japanese beech reflects the distribution and the decay ability of colonized fungi.     

The seasonal occurrence of endophytic fungus, <Emphasis Type="Italic">Mycosphaerella buna</Emphasis>, in Japanese beech, <Emphasis Type="Italic">Fagus crenata</Emphasis>

The seasonal occurrence of Mycosphaerella buna in leaves and contiguous organs of Fagus crenata was studied in a Japanese beech forest, Ibaraki, Japan, in 1998 and 1999. Mycosphaerella buna was not isolated from newly developed leaves in May, but it was isolated from asymptomatic leaves after June. The frequency of its occurrence gradually increased until leaffall. In contrast, M. buna was not isolated from overwintered buds, leaf petioles, or contiguous current-year twigs. The spermogonia and pseudothecia were observed in dead leaves after leaffall. The mature pseudothecia were found on dead leaves from May to July. The ascospores produced in the pseudothecia were suggested to infect newly developed leaves.Contribution no. 173, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan