High viscosity and anisotropy characterize the cytoplasm of fungal dormant stress-resistant spores

Ascospores of the fungus Talaromyces macrosporus are dormant and extremely stress resistant, whereas fungal conidia--the main airborne vehicles of distribution--are not. Here, physical parameters of the cytoplasm of these types of spores were compared. Cytoplasmic viscosity and level of anisotropy as judged by spin probe studies (electron spin resonance) were extremely high in dormant ascospores and during early germination and decreased only partly after trehalose degradation and glucose efflux. Upon prosilition (ejection of the spore), these parameters fell sharply to values characteristic of vegetative cells. These changes occurred without major volume changes that suggest dramatic changes in cytoplasmic organization. Azide reversibly inhibited prosilition as well as the decline in cytoplasmic parameters. No organelle structures were observed in etched, cryoplaned specimens of ascospores by low-temperature scanning electron microscopy (LTSEM), confirming the high cytoplasmic viscosity. However, cell structures became visible upon prosilition, indicating reduced viscosity. The viscosity of fresh conidia of different Penicillium species was lower, namely, 3.5 to 4.8 cP, than that of ascospores, near 15 cP. In addition the level of anisotropic motion was markedly lower in these cells (h(0)/h(+1) = 1.16 versus 1.4). This was confirmed by LTSEM images showing cell structures. The decline of cytoplasmic viscosity in conidia during germination was linked with a gradual increase in cell volume. These data show that mechanisms of cytoplasm conservation during germination differ markedly between ascospores and conidia.     

Parental tracking in the postfire wood decay ascomycete Daldinia loculata using highly variable nuclear gene loci

The origin of the male and female gametes involved in fertilization events within a local population of the postfire wood decay ascomycete Daldinia loculata was investigated by genotyping the mycelia growing in the wood and the sexual ascospores, using three highly variable nuclear gene loci. The study was conducted in a geographically isolated burned forest site in southern Sweden. An intensive sampling was performed by collecting stromata containing ascospores and wood samples containing mycelia. In total, from 32 mapped burned birches, cultures of 22 haploid genets from decayed wood and six ascospores from each of 19 stromata were isolated and analysed. In 80% of the investigated burned branches, only one genet was found. From the analysis of the ascospore genotypes, we detected 30 fertilization events and 60% of them were the result of mating between conidia (clonal propagules) acting as male gametes and the genets in the branches representing the female gametes. The male parents producing the conidia were detected within the same local population as the female parents in 27% of the fertilization events and originated either from the same branch or from different trees located at 0.5-36 m away from the female parents. In 33% of the fertilization events, conidia originated from three male parents that were not found within the local population sampled. These parents could be anywhere inside or outside the sampled area. For the remaining fertilization events, we could not rule out the ascospores or the conidia as fertilizing propagules. No strong evidence for fertilization by recombinant propagules (ascospores) was detected in this study. The pyrophilous insect species associated with conidia of D. loculata are suggested to be essential vectors for the realization of the sexual cycle of this fungal species. By feeding on the conidia and flying between nearby trees inhabiting wood decay mycelia, these insects allow the transfer of conidia and therefore the opposite mating types to meet within a localized burned forest site.     

圆盘菌科无性型有性生殖能力评估

本文评估了分离自子囊孢子和分生孢子的圆盘菌科无性型有性生殖能力。结果表明,由子囊孢子和分生孢子萌发获得的菌株的有性生殖能力具有显著差异,这可能决定于不同的遗传特性。该试验支持了一种假说：仅能进行无性生殖的无性型菌株,很可能来源于逐渐丧失了有性生殖能力的全型菌株。     

具有无色子囊孢子的木霉属两新种

报道了采自我国安徽省金寨县天堂寨的木霉属 Trichoderma 两个新种。新种天堂寨木霉T. tiantangzhaiense位于Hypocreanum分支,子座黄褐色至淡褐色,平垫状至盘状,子囊孢子相对较小;新种余氏木霉T. yui与沃格玛木霉T. voglmayrii亲缘关系较近,具有橙褐色至金棕色子座,褐色至红褐色孔口区和绿色分生孢子。本文提供了这两种木霉宏观和微观特征的详细描述及图示,并探讨了其分类地位。     

Two new species of Neosartorya isolated from soil in Xinjiang, China

Two new species, Neosartorya shendaweii and N. tsunodae, isolated from soil in Xinjing, China and in Pernambuco, Brazil, are described and illustrated. The first species is characterized by its ascospores with two widely separated equatorial crests and tuberculate to verrucose convex surfaces. This species has affinities with several known species of the genus, bearing ascospores with a similar ornamentation, but can be distinguished from these species by other morphological characteristics such as smaller cleistothecia and conidiophores, spathulate vesicles and rather ellipsoidal conidia. The second species is characterized by its unique ascospores with two low equatorial crests, an evident furrow as a deep depression, and finely reticulate convex surfaces. The validation of these new species is supported further by analyses of the β-tubulin, calmodulin and actin gene sequences.     

Aspergillus osmophilus sp. nov., and a new teleomorph for A. proliferans

A new species of Aspergillus and a new teleomorph for A. proliferans, both isolated from cereals in Iran, are described using morphological and molecular data. A combined sequence dataset of the ITS region, partial β-tubulin and partial calmodulin genes resolved the relationships of members of section Aspergillus largely in concordance with morphological traits of ascospores. Aspergillus osmophilus sp. nov. is differentiated from the closest species, A. xerophilus by possessing larger ascospores, conidia and associated fruiting bodies. Both species are strongly xerophilic and possess ascospores with lobate-reticulate convex surfaces. The newly discovered teleomorph for A. proliferans is characterized by delicately roughened ascospores with a shallow or distinct furrow and finely roughened to irregular equatorial crests.     

Two new species of Pseudogymnoascus with Geomyces anamorphs and their phylogenetic relationship with Gymnostellatospora

Two new psychrophilic Pseudogymnoascus species with Geomyces anamorphs are described from a Sphagnum bog in Alberta, Canada. Pseudogymnoascus appendiculatus has long, branched, orange appendages and smooth, fusoid to ellipsoidal ascospores with a faint longitudinal rim. Pseudogymnoascus verrucosus has short, subhyaline appendages and warty peridial hyphae and ascospores, and both smooth to asperulate and irregularly warty conidia. Both species produce asci in chains, a feature that supports the distinction between this group and Myxotrichum, which produces asci singly. The discovery of species intermediate between Pseudogymnoascus and Gymnostellatospora, in having both ornamented ascospores and Geomyces anamorphs, prompted a re-evaluation of the genera. Sequence analysis of the internal transcribed spacer regions (ITS) of the nuclear ribosomal DNA indicates that the two genera remain distinct and comprise a monophyletic group. Pseudogymnoascus species have smooth to warty or lobate-reticulate ascospores while species of Gymnostellatospora have walnut-shaped spores with distinct longitudinal crests and striations. Anamorphs assignable to the form genus Geomyces are allied with both genera. A key is provided to the four species and varieties of Pseudogymnoascus.     

Three new <Emphasis Type="Italic">Ophiostoma</Emphasis> species with <Emphasis Type="Italic">Pesotum</Emphasis> anamorphs associated with bark beetles infesting <Emphasis Type="Italic">Abies</Emphasis> species in Nikko,Japan

Three species of Ophiostoma possessing Pesotum anamorphs isolated from bark beetles and their galleries infesting Abies species in Nikko, Japan, are described as new species. Ophiostoma nikkoense is characterized by brush-shaped synnemata producing long septate clavate conidia, perithecia with neck, and allantoid ascospores. Ophiostoma microcarpum has smaller perithecia with hyphoid ostiolar hyphae on the neck, and the ascospores are cylindrical or ossiform in side and face views. Ophiostoma abieticola has perithecia without ostiolar hyphae on the neck and produces orange-section-shaped or reniform ascospores.Contribution no. 187, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba     

Two new <Emphasis Type="Italic">Corollospora</Emphasis> species and one new anamorph based on morphological and molecular data

Two new species of the genus Corollospora, namely, C. anglusa sp. nov. with its anamorph Varicosporina anglusa sp. nov. and C. portsaidica sp. nov., which were isolated from the coast of the Mediterranean Sea in Egypt, are described in this article based on morphological and molecular evidence. The two new species have one-septate ascospores. Corollospora anglusa resembles C. gracilis by having narrow one-septate hyaline ascospores; however, they differ in ascomata and ascospore dimensions and in pure culture characteristics. Single-ascospore culture of C. anglusa produces the conidia of its anamorph, whereas an anamorph has not been reported for C. gracilis. Varicosporina anglusa differs from the other two known Varicosporina species by having conidial branches that are filamentous, rectangularly branched, hypha like, and disarticulated into two- or one-celled fragments. Corollospora portsaidica is morphologically similar to C. cinnamomea, but the two species differ in the dimensions, shape, and ornamentation of the ascospores. The new Corollospora species were confirmed to be divergent from other similar Corollospora species based on phylogenetic analyses of partial sequences of the LSU rDNA region.     

Two new heterothallicNeosartorya from African soil

Neosartorya nishimurae andN. otanii, two new heterothallic species isolated from African forest soil, are described and illustrated.Neosartorya nishimurae is characterized by its rapid growth on Czapek and malt extract agras, white cleistothecia, lenticular ascospores with two broad equatorial crests and echinulate convex surfaces, and large ellipsoidal conidia with a lobate-reticulate wall.Neosartorya otanii is characterized by its rapid growth on Czapek and malt extract agars, lenticular ascospores with two widely separated equatorial crests and tuberculate or lobate-reticulate convex surfaces, and globose to broadly ellipsoidal conidia with a micro-tuberculate wall.     

Study on the overwintering of cleistothecia and conidia of Erysiphe betae causal agent of sugar beet powdery mildew in Iran

Sugar beet leaves covered by sexual (cleistothecia) and asexual forms (mycelia and conidia) of Erysiphe betae were gathered at harvest time and maintained under natural outdoor conditions. In order to determine the function of cleistothecia and also conidia in the overwintering of E. betae some experiments were performed. The results showed that ascospores were unable to be released in petri dishes but their release under natural conditions occurred after 4 months. Under In vitro conditions ascospores did not germinate but on the leaves germination was rarely possible, however these ascospores were degraded after 7 days and didn't have pathogenicity. Conidia could induce pathogenicity after 3 but not 4 months. The period after inoculation until appearance of disease symptoms increased with aging of conidia. The results for conidial germination showed that fresh conidia had 80 percent germination on glass slides but it decreased sharply after 2 weeks and reached to 0 percent after 4 weeks. Although their germination on the leaves was not more than 46 percent of fresh conidia but they had good germination after 2 and 4 weeks. The results for the experiment to observe the first appearance of the disease in the field suggested that the first conidia were trapped by spore-trap in early June and the first symptoms appeared 20 days later. The conclusive results showed that ascospores had no function in the survival of the fungus and air-borne conidia are the main source of primary infections.     

Lignicolous freshwater Ascomycota from Thailand: Hymenoscyphus varicosporoides and its Tricladium anamorph

A Tricladium anamorph for the discomycete Hymenoscyphus varicosporoides was established in culture from both conidia and ascospores collected in KhaoYai National Park, Thailand, and is compared with Tricladium indicum and T. marylandicum. Hymenoscyphus varicosporoides is compared with Cudoniella indica.     

Neosartorya sublevispora, a new species of soil-borne Eurotiales

A new species ofNeosartorya, N. sublevispora (anam.Aspergillus sublevisporus), is described and photographed. The species is characterized by non-ostiolate ascomata covered loosely with a pale yellowish hyphal envelope, lenticular ascospores with two low equatorial crests, and subglobose to ellipsoidal, microtuberculate conidia. The ornamentation of ascospores, which is composed of two closely appreassed crests and small even-sized echines on their convex surfaces, particularly serves to distinguish this species from other recognized species. A revised key to all accepted species of the genus is provided.     

Two new species of Botryosphaeria with brown, 1-septate ascospores and Dothiorella anamorphs

Botryosphaeria sarmentorum sp. nov. and B. iberica sp. nov. are described and illustrated. These two species are unusual in this genus because of their brown, 1-septate ascospores. Phylogenetic analysis based on ITS and EF1-alpha sequences place them within the clade containing species with Fusicoccum anamorphs. The brown, 1-septate conidia, however, do not conform to Fusicoccum. Therefore phylogenetically and morphologically the anamorphs of these two species belong in a genus distinct from any of the currently accepted anamorph genera assigned to Botryosphaeria. Through a study of the type species of Dothiorella this genus is resurrected to accommodate anamorphs of Botryosphaeria with brown, 1-septate conidia. Botryosphaeria sarmentorum is shown to be the teleomorph of Diplodia sarmentorum, which in turn is transferred to Dothiorella. Otthia quercus is transferred to Botryosphaeria as B. quercicola nom. nov.     

The seasonal release of spores of Nectria galligena from apple cankers in Northern Ireland

Trapping of ascospores and conidia of Nectria galligena Bres. released from cankers on Bramley's Seedling apple trees over a period of three years showed that ascospores were most prevalent in the spring and early summer, and conidia from early summer to late autumn. Few ascospores were released in late summer or mid-winter but a minor period of discharge occurred in autumn. The distribution of cankers within trees in various orchards was also examined, and most were found to occur at the junctions of different seasons' growth. Possible reasons for this are discussed.     

Two new species of Aspergillus section Fumigati isolated from caatinga soil in the State of Pernambuco,Brazil

Aspergillus caatingaensis and A. pernambucoensis, isolated from semi-desert soil in caatinga area, the State of Pernambuco, Brazil, are described and illustrated. Aspergillus caatingaensis is characterized by its white cleistothecia, broadly lenticular ascospores with four equatorial crests and irregularly ribbed to slightly reticulate with aculeate convex surfaces, and ellipsoidal to broadly ellipsoidal conidia with a smooth wall. Aspergillus pernambucoensis is characterized by its, white cleistothecia, lenticular ascospores with two equatorial crests and irregularly ribbed with tuberculate to verrucate convex surfaces, and ovoid to broadly ellipsoidal conidia with a smooth wall. The validation of these new species is supported further by analyses of the β-tubulin, calmodulin and actin gene sequences.     

Filamentous fungi exposed to spaceflight stresses including known levels of ultraviolet irradiations

Chaetomium globosum ascospores andTrichophyton terrestre conidia were exposed to spaceflight parameters of Apollo 16 then returned to Earch for studies in hyphal grwoth dynamics as one of the postflight investigations. Selected phenotypic strains of each species appeared to show changes in growth according to specific ultraviolet irradiations in space.     

Two new <Emphasis Type="Italic">Cordyceps</Emphasis> species from a community forest in Thailand

Two new species found in northern Thailand, Cordyceps chiangdaoensis and Cordyceps morakotii, pathogenic to Coleoptera larvae and Odontomachus ant pupae, respectively, are described using morphological and molecular phylogenetic data. Both species produce narrowly ovoid superficial perithecia at the end of a cylindrical stroma, bola ascospores, Evlachovaea-like conidial morph, and cylindrical conidia with rounded ends. These two species differ from other bola ascospore-producing species in the genus Cordyceps in the sizes of the ascospores and perithecia, as well as the host. Phylogenetic analyses based on internal transcribed spacer (ITS) regions of the rDNA and partial sequences of translation elongation factor 1-alpha (TEF1) data strongly support these two fungi as two distinct new species in the Cordycipitaceae.     

<Emphasis Type="Italic">Hypocrea phyllostachydis</Emphasis> and its <Emphasis Type="Italic">Trichoderma</Emphasis> anamorph,a new bambusicolous species from France

Hypocrea phyllostachydis was collected from the bamboo species Phyllostachys bambusoides in southwestern France (Dept. Pyréneés Atlantiques). It can be distinguished from other morphologically similar species by the small subglobose or broadly ellipsoidal conidia and small ascospores. Conidiophores of the Trichoderma state of H. phyllostachydis do not branch in a pyramidal fashion, as is typical of most species of Trichoderma. Rather, it has an irregular branching pattern, with a long central axis and relatively short lateral secondary branches. A key to species of Hypocrea with green ascospores from France is presented.