Studies in Mycology最新文献

The genus Ceratostomella has a long history of taxonomic confusion. While species with evanescent asci have been transferred to the Microascales and Ophiostomatales, the taxonomic status of species with persistent asci has not been completely resolved. In previous studies using DNA sequence data, cultures and morphology, several Ceratostomella spp. were allocated in 13 genera in the Eurotiomycetes and Sordariomycetes. In our study, the systematics of the remaining Ceratostomella spp. with persistent asci is revisited with new collection data, cultures and phylogeny based on novel DNA sequences from six nuclear loci. Bayesian inference and Maximum Likelihood analyses support the monophyly of several wood-inhabiting species formerly classified in Ceratostomella and other unknown morphologically similar taxa and their division into four genera, i.e. Lentomitella, Spadicoides, Torrentispora and the newly described Calyptosphaeria. This robust clade represents the order Xenospadicoidales in the Sordariomycetidae. Comparative analysis of the ITS2 secondary structure revealed a genetic variation among Lentomitella isolates; 11 species were recognised, of which five are newly introduced and two are new combinations. Other taxonomic novelties include four new species and eight new combinations in Calyptosphaeria, Spadicoides, and Torrentispora. Molecular data suggest that Spadicoides is polyphyletic. The core of the genus is positioned in the Xenospadicoidales; Spadicoides s. str. is experimentally linked with sexual morphs for the first time. Based on DNA sequence data, the monotypic genera Xenospadicoides and Pseudodiplococcium are reduced to synonymy under Spadicoides, while Fusoidispora and Pseudoannulatascus are synonymised with Torrentispora. Members of the Xenospadicoidales inhabit decaying wood in terrestrial and freshwater environments and share a few morphological characters such as the absence of stromatic tissue, ascomata with a cylindrical or rostrate neck, similar anatomies of the ascomatal walls, thin-walled unitunicate asci with a non-amyloid apical annulus, disintegrating paraphyses, usually ellipsoidal to fusiform ascospores and holoblastic-denticulate or tretic conidiogenesis. Revised Ceratostomella spp. with persistent asci are listed and the taxonomic status of each species is re-evaluated based on revision of the holotype and other representative material, published details and available phylogenetic data.

Late blight, caused by the oomycete pathogen Phytophthora infestans, is the most devastating disease in potato. For sustainable management of this economically important disease, resistance breeding relies on the availability of resistance (R) genes. Such R genes against P. infestans have evolved in wild tuber-bearing Solanum species from North, Central and South America, upon co-evolution with cognate avirulence (Avr) genes. Here, we report how effectoromics screens with Avr2 of P. infestans revealed defense responses in diverse Solanum species that are native to Mexico and Peru. We found that the response to AVR2 in the Mexican Solanum species is mediated by R genes of the R2 family that resides on a major late blight locus on chromosome IV. In contrast, the response to AVR2 in Peruvian Solanum species is mediated by Rpi-mcq1, which resides on chromosome IX and does not belong to the R2 family. The data indicate that AVR2 recognition has evolved independently on two genetic loci in Mexican and Peruvian Solanum species, respectively. Detached leaf tests on potato cultivar ‘Désirée’ transformed with R genes from either the R2 or the Rpi-mcq1 locus revealed an overlapping, but distinct resistance profile to a panel of 18 diverse P. infestans isolates. The achieved insights in the molecular R – Avr gene interaction can lead to more educated exploitation of R genes and maximize the potential of generating more broad-spectrum, and potentially more durable control of the late blight disease in potato.

Understanding the mechanisms underlying wood decay basidiomycete community dynamics is crucial for fully understanding decomposition processes, and for modelling ecosystem function and resilience to environmental change. Competition drives community development in decaying woody resources, with interactions occurring at a distance, following physical contact, and through specialised relationships such as mycoparasitism. Outcomes of combative interactions range from replacement, where one mycelium displaces another, to deadlock, where neither combatant captures territory from the other; and a spectrum of intermediate outcomes (i.e. partial or mutual replacement) lie between these extremes. Many wood decay basidiomycetes coexist within a resource, in a complex and dynamic community, and new research techniques are focussing on spatial orientation of interactions in 3 dimensions, as opposed to historical two-dimensional research. Not only do interactions drive changes in species composition and thus wood decomposition rate, they also may have industrial applications in biocontrol of pathogenic or nuisance fungi, enzyme production, and in the production of novel antifungals and antibiotics. Altogether, fungal interactions are a fascinating and important field of study.

Late blight disease caused by the plant pathogenic oomycete pathogen Phytophthora infestans is one of the most limiting factors in potato production. P. infestans is able to overcome introgressed late blight resistance by adaptation of effector genes. AVR1 is an RXLR effector that triggers immune responses when recognized by the potato resistance protein R1. P. infestans isolates avirulent on R1 plants were found to have AVR1 variants that are recognized by R1. Virulent isolates though, lack AVR1 but do contain a close homologue of AVR1, named A-L, of which all variants escape recognition by R1. Co-expression of AVR1 and R1 in Nicotiana benthamiana results in a hypersensitive response (HR). In contrast, HR is not activated when A-L is co-expressed with R1. AVR1 and A-L are highly similar in structure. They share two W motifs and one Y motif in the C-terminal part but differ in the T-region, a 38 amino acid extension at the carboxyl-terminal tail of AVR1 lacking in A-L. To pinpoint what determines R1-mediated recognition of AVR1 we tested elicitor activity of AVR1 and A-L chimeric and deletion constructs by co-expression with R1. The T-region is important as it enables R1-mediated recognition of A-L, not only when fused to A-L but also via trans-complementation. Yet, AVR1 lacking the T-region is still active as an elicitor of HR, but this activity is lost when certain motifs are swapped with A-L. These data show that A-L circumvents R1 recognition not only because it lacks the T-region, but also because of differences in the conserved C-terminal effector motifs.

As part of a worldwide survey of the indoor mycobiota about 520 new Cladosporium isolates from indoor environments mainly collected in China, Europe, New Zealand, North America and South Africa were investigated by using a polyphasic approach to determine their species identity. All Cladosporium species occurring in indoor environments are fully described and illustrated. Fourty-six Cladosporium species are treated of which 16 species are introduced as new. A key for the most common Cladosporium species isolated from indoor environments is provided. Cladosporium halotolerans proved to be the most frequently isolated Cladosporium species indoors.

Ophiocordyceps is a heterogeneous, species-rich genus in the order Hypocreales (Sordariomycetes, Ascomycota) that includes invertebrate-pathogenic taxa. In this study, seven new species in Ophiocordyceps producing superficial perithecia infecting various insect hosts (Lepidoptera, Hemiptera) are described from Thailand – Ophiocordyceps brunneinigra, O. brunneiperitheciata, O. geometridicola, O. multiperitheciata, O. pauciovoperitheciata, O. pseudoacicularis and O. spataforae. Phylogenetic analyses based on multigene loci comprising the large subunit of the ribosomal DNA (LSU), partial sequences of elongation factor 1-alpha (TEF) and the largest and second largest subunit of the RNA polymerase (RPB1, PRB2) strongly support these new species of Ophiocordyceps in the Ophiocordycipitaceae. They differ from species previously described species Ophiocordyceps acicularis, O. atewensis, O. cochlidiicola, and O. crinalis, in the shape and sizes of distinguishing characters such as perithecia, ascospores and conidia. We also report a new record of O. macroacicularis in Thailand.

The rust fungi (Pucciniales) are the most speciose natural group of plant pathogens, members of which possess the most complex lifecycles in Fungi. How natural selection works on the Pucciniales has been the subject of several hypotheses in mycology. This study uses molecular age estimation using sequence data from multiple loci, and cophylogeny reconciliation analyses to test hypotheses regarding how the aecial and telial stages in the lifecycle of rust fungi may have differentially impacted their diversification. Molecular age estimates show that the timing of diversification in the Pucciniales correlates with the diversification of their gymnosperm and angiosperm hosts. Host reconciliation analyses suggest that systematic relationships of hosts from the aecial stage of the Pucciniales lifecycle better reflect the systematic relationships among the Pucciniales. The results demonstrate the relative importance of this stage on the overall evolution of the Pucciniales and supports hypotheses made by Leppik over half a century ago. This study represents the first evaluation of how different life stages in the Pucciniales shape the evolution of these fungi.

The transition from amateur to professional in natural history is generally regarded as having taken place in the nineteenth century, but landmark events such as the 1917 appointment of mycologist Johanna Westerdijk (1883–1961) as the first female professor in the Netherlands indicate that the pattern of change for women was more varied and delayed than for men. We investigate this transition in mycology, and identify only 43 women in the Western World who published scientific mycological literature pre-1900, of whom twelve published new fungal taxa. By charting the emergence of these women over time, and comparing the output of self-taught amateurs and university graduates, we establish the key role of access to higher education in female participation in mycology. Using a suite of strategies, six of the self-taught amateurs managed to overcome their educational disadvantages and name names — Catharina Dörrien (the first to name a fungal taxon), Marie-Anne Libert, Mary Elizabeth Banning, Élise-Caroline Bommer, Mariette Rousseau, and Annie Lorrain Smith. By 1900, the professional era for women in mycology was underway, and increasing numbers published new taxa. Parity with male colleagues in recognition and promotion, however, remains an ongoing issue.

Aspergillus section Aspergillus (formerly the genus Eurotium) includes xerophilic species with uniseriate conidiophores, globose to subglobose vesicles, green conidia and yellow, thin walled eurotium-like ascomata with hyaline, lenticular ascospores. In the present study, a polyphasic approach using morphological characters, extrolites, physiological characters and phylogeny was applied to investigate the taxonomy of this section. Over 500 strains from various culture collections and new isolates obtained from indoor environments and a wide range of substrates all over the world were identified using calmodulin gene sequencing. Of these, 163 isolates were subjected to molecular phylogenetic analyses using sequences of ITS rDNA, partial β-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) genes. Colony characteristics were documented on eight cultivation media, growth parameters at three incubation temperatures were recorded and micromorphology was examined using light microscopy as well as scanning electron microscopy to illustrate and characterize each species. Many specific extrolites were extracted and identified from cultures, including echinulins, epiheveadrides, auroglaucins and anthraquinone bisanthrons, and to be consistent in strains of nearly all species. Other extrolites are species-specific, and thus valuable for identification. Several extrolites show antioxidant effects, which may be nutritionally beneficial in food and beverages. Important mycotoxins in the strict sense, such as sterigmatocystin, aflatoxins, ochratoxins, citrinin were not detected despite previous reports on their production in this section. Adopting a polyphasic approach, 31 species are recognized, including nine new species. ITS is highly conserved in this section and does not distinguish species. All species can be differentiated using CaM or RPB2 sequences. For BenA, Aspergillus brunneus and A. niveoglaucus share identical sequences. Ascospores and conidia morphology, growth rates at different temperatures are most useful characters for phenotypic species identification.

Scopulariopsis-like species are often reported from the indoor environment, as well as from clinical samples. The lack of type isolates and thorough phylogenetic studies in the Microascaceae hampered the correct identification of these isolates. Based on recent phylogenetic studies, which resulted in multiple name changes, the aim is to molecularly identify the Scopulariopsis and scopulariopsis-like species which occur in the indoor environment and give an overview of the current species in these genera and their habitats. Strains from the CBS culture collection were supplemented with almost 80 indoor strains of which the internal transcribed spacer 1 and 2 and intervening 5.8S nrDNA (ITS), beta-tubulin (tub2) and translation elongation factor 1-alpha (tef1) gene regions were sequenced for phylogenetic inference. The multi-gene phylogenies recognise 33 Microascus species and 12 Scopulariopsis species and showed that the recently established genus Fuscoannellis, typified by Scopulariopsis carbonaria, should be synonymized with the genus Yunnania. Seven new Microascus species, four new Scopulariopsis species, and one new Yunnania species, are described, and a new name in Microascus and two new name combinations (one in Microascus, and one in Yunnania) are proposed. In the indoor environment 14 Microascus species and three Scopulariopsis species were found. Scopulariopsis brevicaulis (22 indoor isolates) and Microascus melanosporus (19 indoor isolates) are the most common indoor species, in number of isolates, followed by M. paisii (8 indoor isolates) and S. candida (7 indoor isolates). A genus phylogeny based on the ITS, tef1 and the large subunit 28S nrDNA (LSU) of the type or representative isolates of all here recognised species is provided depicting all species habitats. No correlation between phylogenetic relationship and habitat preference could be observed. Ten species which are found indoor are also found in relation with human-derived samples. A table showing recent name changes and a key to common species of Scopulariopsis and scopulariopsis-like genera found indoors is included.