Onygenales: the dermatophytes, dimorphics and keratin degarders in their evolutionary context.

Details: 220pp., fully illustrated with colour pictures (A4 format), paperback, 2002
Price: € 55,-

Phylogeny of Ajellomyces, Polytolypa and Spiromastix (Onygenaceae) inferred from rDNA sequence and non-molecular data.

W. A. Untereiner1,5, J. A. Scott2, F. A. Naveau3, R, S. Currah4 and J. Bachewich1

1 Department of Botany, Brandon University, Brandon, Manitoba R7A 6A9, Canada, 2 Department of Public Health Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada, 3 Euroscreen, Brussels, B-1070 Belgium, 4 Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.

Abstract: Phylogenetic relationships within the Onygenales were inferred from maximum parsimony analyses of partial nuclear large ribosomal RNA subunit (nucLSU) sequences for 46 members of this order. The inferred phylogeny supports the division of the Onygenales into a number of separate lineages, two of which correspond to the Arthrodermataceae and Gymnoascaceae. The Onygenaceae, as circumscribed currently, is not monophyletic, and although the members of this family can be divided into a number of well-supported groups, the relationships among many of these taxa and their position relative to the Gymnoascaceae remain unresolved in our sequence-based phylogenies. Shanorella is more closely allied to the Arthrodermataceae than to the Onygenaceae. Our phylogenies provide additional evidence that a number of the morphological characters used to distinguish members of the Onygenales are of limited value for inferring phylogenetic relationships. Analysis of a data set that includes 12 non-molecular characters, partial nucLSU and mitochondrial small subunit RNA sequences (1406 bp) for a subset of eight taxa provides strong evidence for the close association of Spiromastix grisea and the dimorphic pathogen Ajellomyces dermatitidis. The new combination, Ajellomyces grisea (Currah & Locquin-Linard) Untereiner & Scott, is proposed.

Key words: anamorph, human-pathogenic fungi, molecular systematics, Onygenales, peridial appendages, ribosomal RNA gene sequences.

Molecular phylogeny of onygenalean fungi based on small subunit (SSU) and large subunit (LSU) ribosomal DNA sequences 1

M. Sugiyama1, R.C. Summerbell2 and T.Mikawa1

1MCC group Science and Technology Research Center, Mitsubishi Chemical Corp., 1000, Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa, 227-8502, Japan; 2Centraalbureau voor Schimmelcultures, Utrecht, the Netherlands

Abstract: The phylogenetic relationships of the three families of the Onygenales (Arthrodermataceae, Gymnoascaceae and Onygenaceae) were analyzed based on small subunit (SSU) rDNA (ca. 1685 bp.) and large subunit (LSU) rDNA (including domains D1 and D2, ca. 570 bp.) sequences. Phylogenetic trees were constructed using the neighbor-joining and maximum-likelihood methods combined with rate-homogeneous and -heterogeneous models. Maximum parsimony was also used for construction of the phylogenetic tree from the combined data set of both genes. The tree topology for the whole of the onygenalean taxa was evaluated by adding the log likelihoods of each tree calculated for the SSU and LSU data sets. Four major clades (clade I-IV) were recognized in the phylogenetic tree based on the combined data set for 27 representative taxa in the Onygenales. Phylogenetic structures of each clade were analyzed in detail based on LSU rDNA sequences. Clade I included both systemic pathogens and saprotrophic onygenaceous taxa as shown by us in a previous study. Clade II mainly consisted of the Gymnoascaceae, although the subclade structure did not reflect the variation in ascospore morphology within the clade. The rest of the onygenaceous taxa were divided into two independent clades, clades III and IV. The Arthrodermataceae comprised clade III. Thus, the currently recognized family Onygenaceae consisted of an assemblage of three independent clades. The distribution and evolution of major phenotypic characters of the Onygenales were discussed. The tree topologies suggested that keratinolytic ability was apomorphic in onygenalean evolution. Oblate, pitted ascospores and rhexolytic arthroconidia like those of Malbranchea were probably plesiomorphic, whereas smooth-surface and discoid ascospores, solitary aleurioconidia like those of Histoplasma, multiseptate macroconidia like those of Microsporum, and stroma-like ascocarps of Onygena were probably apomorphic. These characters sometimes showed wide variations even within a subclade, and it was difficult to define a clade by a single character state of these characters or their combination. The phylogenetic structures of the Onygenaceae and the Arthrodermataceae were not reflected in the current classification system based on the differences of ascospore ornamentation, anamorph morphology and substrate preferences. Re-evaluation of the Onygenaceae and the Arthrodermataceae is necessary, and the significance assigned to phenotypic characters needs to be reviewed.

Key Words: small subunit (SSU), rDNA, large subunit (LSU) rDNA, Onygenales, phylogeny

Phylogeny of Onygenalean fungi of medical interest

J. Guarro & J. Cano*

Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, Institut d’Estudis Avançats, Universitat Rovira i Virgili, 43201-Reus, Tarragona, Spain


Molecular analyses of different ribosomal DNA gene regions have demonstrated that traditional taxonomy of the Onygenales, especially in suprageneric classification, can no longer be supported. This was well illustrated by a comparative analysis of the ribosomal internal transcribed spacer region of 140 strains belonging to 100 species, including teleomorphs and anamorphs. Most of the teleomorph genera of clinical interest were monophyletic. Seven well-supported clades were obtained, i.e. dermatophytes, Gymnoascus, Ajellomyces (which as a clade includes Histoplasma, Paracoccidioides brasiliensis, Blastomyces dermatitidis and Emmonsia), Arachnomyces, Auxarthron, Uncinocarpus (which includes Coccidioides immitis) and Aphanoascus. The topology of the phylogenetic tree was consistent with a taxonomic scheme based on the key physiological and morphological features shown by these fungi. Important features in this scheme include keratinophilic capability and the ascospore ornamentation. Less important are the ascospore shape and the type of ascomatal wall.

F1SS polysaccharides: chemotaxonomic characters and evolutionary indicators for Plectomycetes

O. Ahrazem1, A. Prieto1, M. Bernabé2 and J. A.Leal1*.

1Centro de Investigaciones Biológicas. CSIC. Velázquez, 144. 28006-Madrid. SPAIN. and 2Instituto de Química Orgánica. Departamento de Química Orgánica Biológica. CSIC. Juan de la Cierva, 3. 28006-Madrid. SPAIN.

Abstract: The cell wall alkali-extractable water-soluble F1SS polysaccharides from members of the orders Onygenales and Eurotiales have been characterized. In Arthrodermataceae and Onygenaceae the polysaccharide consists of a ?6)-?-D-Manp-(1? chain, whose mannose residues are partially or completely substituted at O-2 by ?-D-Manp-(1?. In the polysaccharide of certain species, some of the terminal mannose residues are substituted at O-3 by a methyl group or at O-6 by an additional residue of ?- or ?-D-Galf-(1?. The F1SS polysaccharide from Trichocomaceae consists of a small core of ?6)-?-D-Manp-(1? to which chains of galactofuranose are linked. The polysaccharides from members of the Myxotrichaceae contain rhamnose in addition to galactofuranose and mannose. The distribution of these polysaccharides reveals potential links between teleomorphs and anamorphs based on similar chemistry, as well as the existence of misplaced species and genera in the taxonomic arrangements of the Plectomycetes. F1SS polysaccharides seem to have evolved from their primitive condition, mannose homopolymers and mannans substituted by single residues of galactofuranose, as found in Onygenales, to a derived condition, galactomannans, as seen in Eurotiales. These polysaccharides can be utilized as chemotaxonomic and evolutionary indicators in the Plectomycetes.

Chitin synthase 1 and 2 genes of dermatophytes

R.Kano1*, Y.Nakamura2, S.Watanabe2 and A.Hasegawa1

1Department of Pathobiology, Nihon University School of Veterinary Medicine,1866, Kameino, Fujisawa, Kanagawa, 2528510, Japan, 2Department of Dermatology, Teikyo University School of Medicine, 11-1, Kaga, Itabashi-ku, Tokyo, 173-8605, Japan

Abstract: The full length of chitin synthase (CHS) 1 and 2 genes of Arthroderma benhamiae (one of the teleomorphs within the Trichophyton mentagrophytes complex) was sequenced by the 5'- rapid amplification of cDNA ends (RACE) and 3'-RACE methods using cDNA as a template. The full-length cDNA sequences of the CHS1 (3158 bp) and CHS2 (3392 bp) genes encode 890 and 419 amino acids, respectively. The amino acid sequences of A. benhamiae CHS1 and CHS2 genes in the conserved regions showed respectively about 70 % and 80 % similarity to those of the other filamentous ascomycetes registered in GenBank. Southern hybridization analysis of genomic DNA with a CHS1 probe gave three distinct bands in BamHI, EcoRI, HindIII and Pst1 digests of genomic DNA from A. benhamiae, while analysis with a CHS2 probe gave two distinct bands in EcoRI digests and one band in BamHI, HindIII and Pst1 digests. Reverse transcriptase (RT)-PCR analysis suggested that chitin synthase inhibitors (nikkomycin Z and polyoxin D) might stimulate the expression of CHS1 mRNA in A. benhamiae, and not the expression of CHS2 mRNA. Phylogenetic analysis of CHS2 gene fragments of eight dermatophyte species revealed that the genera Epidermophyton, Microsporum and Trichophyton were genetically different from each other, as was also seen in CHS1 analysis.

Development of DNA markers to explore host shifts in dermatophytes

S. Probst1, G.S. de Hoog2, and Y. Gräser1

1Institute of Microbiology and Hygiene (Charité), Humboldt University, Dorotheenstr. 96, D-10117 Berlin, Germany, 2Centraalbureau voor Schimmelcultures, P.O. Box 85167, NL-3508 AD Utrecht, The Netherlands, and Institute for Biodiversity and Ecosystem Dynamics, Kruislaan 398, NL-1098 SM Amsterdam, The Netherlands

Abstract: Recent molecular studies of the ribosomal operon have shown that pairs of zoophilic and anthropophilic Trichophyton species can be found closely together within single monophyletic branches. In Trichophyton schoenleinii (anthropophilic) and T. mentagrophytes (zoophilic) this kinship is supported by the occurrence of favus-like clinical pictures in humans as well as in animals. Thirty-two isolates were investigated for seven further markers in an attempt to support the phylogenetic relationship of T. mentagrophytes and T. schoenleinii; altogether 8860 bp were sequenced. The data confirm the genetic isolation of the two species. T. schoenleinii is nearly monomorphic. The revised concept of T. mentagrophytes includes the variety T. m. var. quinckeanum as well as isolates, including ex-type isolates where known, originally described as T. sarkisovii, T. langeronii, T. depressum and T. papillosum. T. mentagrophytes as redefined is more heterogeneous than T. schoenleinii is. Strains from camels are found in three different clusters, suggesting a long association between fungi and host animal species. A host shift from animals to humans is likely to have occurred only once. For this reason it is advocated that the terms anthropo- and zoophilic should be applied to species rather than to individual strains, indicating their prevalent mode of transmission.

The Trichophyton mentagrophytes complex: biological species and mating type prevalences of North American isolates, and a review of the worldwide distribution and host associations of species and mating types.

R. C. Summerbell1, I. Weitzman2 and A.A. Padhye3

1Centraalbureau voor Schimmelcultures, Utrecht, the Netherlands; 2Sun City West, Arizona; and 3Centers for Disease Control and Prevention, Atlanta, Georgia, USA.

Abstract: Previous studies of the distribution of biological species or potentially interbreeding pools within the Trichophyton mentagrophytes complex have given only a preliminary knowledge of these species in North America. Most such studies have focused on western Europe or Japan, where the teleomorph Arthroderma vanbreuseghemii and corresponding anamorph Trichophyton interdigitale ss. Gräser et al. are greatly predominant. T. mentagrophytes isolates (n = 138) from three North American centres, however, when crossed with tester isolates of A. vanbreuseghemii and the Americano-European and African races of Arthroderma benhamiae, yielded 12 isolates fully fertile with Americano-European A. benhamiae and only one interfertile with A. vanbreuseghemii. This predominance of A. benhamiae among fertile isolates is similar to that reported in eastern Europe. A bias towards isolates of (+) mating type from human sources, a phenomenon seen in European and Asian surveys, was also found in the North American isolates, but only among non-mating isolates. The isolates fully fertile with A. benhamiae were mostly of (–) mating type. Three of the isolates mating with A. benhamiae were powdery in macromorphology and matched the historical, pre-phylogenetic concept of T. interdigitale. Along with the results of previous eastern European studies, this finding indicates that the name T. interdigitale, as currently defined based on molecular studies, cannot be ascribed automatically to all velutinous T. mentagrophytes complex isolates from human sources. The nomenclatural status of anamorphs in the T. mentagrophytes complex, as outlined in recent phylogenetic studies, is further complicated by the previously reported full fertility of T. mentagrophytes var. quinckeanum isolates, currently corresponding to the neotypified T. mentagrophytes ss. stricto, with A. benhamiae. This teleomorph was recently stated to have Trichophyton erinacei (sensu lato) as its corresponding anamorph. Analysis of recent literature suggests that zoophilic members of the T. mentagrophytes complex normally associate with distinctive host animals, e.g., A. benhamiae with rabbits, guinea pigs and hedgehogs; this may be a factor in regional prevalence rates seen among infected humans.

Exploratory study of single-copy genes and ribosomal intergenic spacers for rapid distinction of dermatophytes

A. K. Gupta 1 Y. Kohli 2 and R. C. Summerbell 3

1Division of Dermatology, Department of Medicine, Sunnybrook Health Science Center and Women’s College Hospital (Sunnybrook site), and the University of Toronto, Canada., 2Department of Clinical Microbiology, The Hospital for Sick Children, Toronto, Ontario, Canada and 3Centraalbureau voor Schimmelcultures, Utrecht, the Netherlands.

Abstract: In a survey directed at finding new methods for rapid distinction of dermatophyte species and other fungi from nails and skin, a number of putative single-copy genes, including calmodulin, actin, ß-tubulin, and elongation factor 1 were screened for PCR amplicon size polymorphisms. Also, two different sets of primers for the ribosomal intergenic spacer (IGS), including one specific for the RNA polymerase 1 promoter region, were surveyed. Single-strand conformational polymorphism (SSCP) analysis was performed to detect interspecific polymorphisms in the IGS regions as well as three of the four single-copy genes. The results were compared to those of two established techniques, namely, the use of arbitrarily primed polymerase chain reaction and the detection of restriction fragment length polymorphisms in the IGS region using a 1220 bp fragment of the rDNA region as a probe in hybridizations. Primers based on the conserved region of the calmodulin gene yielded specific amplification patterns for clades consisting of Trichophyton rubrum and closely related species (e.g., T. soudanense), T. interdigitale and closely related species (e.g., T. tonsurans), and T. terrestre. Four Microsporum species tested as well as Epidermophyton floccosum also had distinct amplification patterns. Dermatophyte calmodulin patterns were different from those seen in the non-dermatophyte moulds studied. Amplification of this gene could be used in combination with preliminary morphological characterization to rapidly distinguish atypical T. rubrum and T. interdigitale; such atypical isolates pose a common reference laboratory problem. Calmodulin and ß-tubulin are worthy of further investigation for distinguishing dermatophyte from non-dermatophyte infections in nail and skin specimens. Even in the very sensitive SSCP studies, however, most of the loci studied had less distinguishing power among recognized anthropophilic dermatophyte species than phenotypic examination had; most notably, few could be used in distinguishing the T. violaceum-T. soudanense cluster from T. rubrum. The other rapid molecular techniques employed suffered similar resolution problems, especially with T. soudanense and T. rubrum. It is concluded that these problems are rooted in the recent evolutionary dispersion of the anthropophilic dermatophytes: in these organisms, housekeeping genes and non-coding regions appear to have undergone normal, relatively low rates of population-level fixation of mutations, whereas many of the as yet uncharacterized genes coding for different morphologies, physiologies, ecologies and epidemiologies in these species are likely to have been rapidly fixed in the relevant populations by means of selective sweeps occurring after profound changes such as host switching or geographic shift. Thus investigations of adaptively more-or-less neutral loci, while allowing some discrimination of related species, tend to give similar monotonous results that stand in strong contrast to the dramatic phenotypic and niche alterations seen.

What is the evolutionary and taxonomic status of asexual lineages in the dermatophytes?

Richard C. Summerbell

Centraalbureau voor Schimmelcultures, Utrecht, the Netherlands.

Abstract: Based on a model of their evolution and on the molecular evidence to date, it is suggested that most distinct, asexual, single-mating-type lineages occurring within the dermatophytes should be conceptualized as species. This applies not only to traditionally accepted taxa such as Trichophyton rubrum and Microsporum audouinii, but also to some less phenotypically distinguished groups such as the core group of anthropophilic Trichophyton interdigitale isolates. The same suggestion is tentatively made, in view of the absence of evidence for natural introgression, for some single-mating-type lineages such as Trichophyton erinacei ss. str. that have been shown to be capable of interbreeding with related fully sexual lineages in vitro but apparently do not do so in nature. The term “unifactorial radiate lineages” is defined to denote these non-sexually-reproducing lineages that are derived from a sexual ancestor but consist of a single mating type and have undergone a host shift separating them from the sexual descendants of the same ancestor.

Two new species of Auxarthron morphologically and genetically close to A. kuehnii

Solé, M., Cano, J.*, Stchigel, A.M. & Guarro, J.

Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, Institut d’Estudis Avançats, Universitat Rovira i Virgili, 43201-Reus, Tarragona, Spain

Abstract: Auxarthron kuehnii is a keratinophilic species of the Onygenales with morphological features intermediate between those of Auxarthron and Amauroascus. We examined numerous strains from various sources, all identified as A. kuehnii by various authors, and we observed important variations in the main phenotypic characters. A sequence analysis based on the ribosomal internal transcribed spacer (ITS) region and the intervening 5.8S rDNA gene of these strains confirmed that the taxon was heterogeneous. On this basis, we propose two new species, Auxarthron concentricum and Auxarthron chlamydosporum. A. concentricum can be clearly distinguished from A. kuehnii in that it has yellow colonies and a distinct pattern of ascospore wall reticulation. A. chlamydosporum can be distinguished by its anamorph consisting of arthroconidia that develop into chlamydospore-like cells.


Auxarthron teleomorphs for Malbranchea filamentosa and Malbranchea albolutea and relationships within Auxarthron

L. Sigler,1* S. Hambleton,2 A. L. Flis,1 and J. A. Paré3

1University of Alberta Microfungus Collection and Herbarium, Devonian Botanic Garden, Edmonton, Alberta, Canada T6G 2E1, 2 Eastern Cereal and Oilseed Research Centre, Research Branch, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada K1A 0C6, 3Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA 53706

Abstract: Malbranchea filamentosa and M. albolutea were reexamined and connected to teleomorphs in the genus Auxarthron. DNA sequences were obtained from the small subunit (SSU) and internal transcribed spacer (ITS) regions of the nuclear ribosomal rRNA gene to evaluate conspecificity of the M. filamentosa isolates and to evaluate relationships among taxa within the Auxarthron clade. Five of eight isolates putatively identified as M. filamentosa produced fertile ascomata in matings and with F1 progeny. Auxarthron filamentosum sp. nov. is described for the teleomorph. Three nonmating isolates appeared conspecific based on morphology, but one was excluded based on sequence divergence. An Auxarthron teleomorph was described for M. albolutea in 1976, but not named because of uncertainty about its distinction from A. thaxteri and A. umbrinum. Auxarthron alboluteum sp. nov. is shown to be phylogenetically distinct. Phylogenetic analysis based on newly derived sequences showed that members of the genus Auxarthron and Malbranchea dendritica formed a strongly supported monophyletic group. In the ITS analysis, most species were placed into two well supported clades that correlated with the shape of the ascospores; the position of the type species A. californiense, was not clearly resolved. Differences were found between newly derived SSU sequences and those on deposit in GenBank for the same strains. After re-evaluation of the strains, the following sequences are considered to be incorrect: M. albolutea L28063 (UAMH 2846), A. zuffianum L28062 (UAMH 4098), M. dendritica L28064 (UAMH 2731) and M. filamentosa L28065 (UAMH 4097). The sequence for U29389 is correct for Malbranchea albolutea not M. dendritica as stated in the original GenBank record. The problems with these sequences were not uncovered in prior published analyses because insufficient representatives of Auxarthron species were sampled.

Chlamydosauromyces punctatus gen. & sp. nov. (Onygenaceae) from the skin of a lizard

L. Sigler,1 S. Hambleton,2 and J.A. Paré3

1University of Alberta Microfungus Collection and Herbarium, Devonian Botanic Garden, Edmonton, Alberta, Canada T6G 2E1, 2 Eastern Cereal and Oilseed Research Centre, Research Branch, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada K1A 0C6, 3Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA 53706

Abstract: Chlamydosauromyces punctatus is described for an ascomycete producing punctate, rimmed ascospores within ascomata composed of narrow, thin-walled, branched hyphae and an anamorph of alternate arthroconidia. It is known from a single collection obtained from shed skin of a frilled lizard. DNA sequences from the small subunit (SSU) region of the nuclear ribosomal gene were obtained from the lizard isolate and two other taxa and compared with homologous sequences of onygenalean fungi obtained from GenBank. Phylogenetic analysis supports the inclusion of the genus Chlamydosauromyces within the Onygenaceae. Results also supported the separation of Arachniotus ruber from Kraurogymnocarpa trochleospora (Pseudoarachniotus trochleosporus), a species that at one time was considered synonymous.


Phylogeny of the genus Arachnomyces and its anamorphs and the establishment of Arachnomycetales, a new eurotiomycete order in the Ascomycota

C. F. C. Gibas 1, 2, L. Sigler 1*, R. C. Summerbell 3 and R. S. Currah 2

1University of Alberta Microfungus Collection and Herbarium, Edmonton, Alberta, Canada; 2Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada; 3Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands

Abstract: Arachnomyces is a genus of cleistothecial ascomycetes that has morphological similarities to the Onygenaceae and the Gymnoascaceae but is not accommodated well in either taxon. The phylogeny of the genus and its related anamorphs was studied using nuclear SSU rDNA gene sequences. Partial sequences were determined from ex-type cultures representing A. minimus, A. nodosetosus (anamorph Onychocola canadensis), A. kanei (anamorph O. kanei) and A. gracilis (anamorph Malbranchea sp.) and aligned together with published sequences of onygenalean and other ascomycetes. Phylogenetic analysis based on maximum parsimony showed that Arachnomyces is monophyletic, that it includes the hyphomycete Malbranchea sclerotica, and it forms a distinct lineage within the Eurotiomycetes. Based on molecular and morphological data, we propose the new order Arachnomycetales and a new family Arachnomycetaceae. All known anamorphs in this lineage are arthroconidial and have been placed either in Onychocola (A. nodosetosus, A. kanei) or in Malbranchea (A. gracilis). Onychocola is considered appropriate for disposition of the arthroconidial states of Arachnomyces and thus Malbranchea sclerotica and the unnamed anamorph of A. gracilis are redisposed as Onychocola sclerotica comb. nov. and O. gracilis sp. nov.

Molecular phylogeny of Gymnoascus and related genera

M. Solé, J. Cano*, L. B. Pitarch, A.M. Stchigel & J. Guarro

Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, Institut d’Estudis Avançats, Universitat Rovira i Virgili, 43201-Reus, Tarragona, Spain

Abstract: A phylogenetic study based on the analysis of the sequences of the ITS region and 5.8S rDNA gene of 24 strains belonging to 11 morphologically similar genera of Onygenales has been performed. The analysis supports the morphological evidence of synonymization of the genera Arachniotus, Gymnascella, Gymnoascoideus and Narasimhella with Gymnoascus. The new species Gymnoascus armeniacus characterised by smooth, oblate, ascospores and the new genus and species Testudomyces verrucosus based on two strains previously described as Gymnoascus reticulatus, are proposed. Gymnoascus alatosporus is considered a synonym of Acanthogymnomyces princeps. A key to the accepted species of Gymnoascus is provided.

Molecular taxonomy of Aphanoascus and description of two new species from soil

J. Cano*, M. Sagués, E. Barrio+, P. Vidal, R.F. Castañedaº, J. Gené & J. Guarro

Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, Institut d’Estudis Avançats, Universitat Rovira i Virgili, 43201-Reus, Tarragona, Spain, + "Cavanilles" Institute for Biodiversity & Evolutionary Biology, University of Valencia, Edif. Instituts del Campus de Paterna, P.O. Box 22085, 46071-VALENCIA, Spain and º Instituto de Investigaciones Fundamentales en Agricultura Tropical “Alejandro de Humboldt”, calle 1 esq. 2, Santiago de Las Vegas, Ciudad de La Habana, Cuba.

Abstract: We performed a phylogenetic study of the genus Aphanoascus based on the analysis of sequences of the ITS regions and the 5.8S rRNA gene. In this study a total of 28 strains belonging to 25 species were included. The topology of the phylogenetic trees revealed that the resulting clades corresponded to differently shaped ascospores. The type of ascospore ornamentation was revealed as a relatively unimportant phylogenetic character. The molecular analysis supported the proposal of two new species and confirmed their morphological distinction from the other species of the genus. The new species are Aphanoascus cubensis, characterized by ascospores with an irregularly tuberculate wall and two inconspicuous equatorial rims, and A. pinarensis with ascospores with an irregularly reticulate wall and two prominent and delicate equatorial rims. Both species have a Chrysosporium anamorph. The new combinations Aphanoascus foetidus and A. orissi are also proposed.

Castanedomyces australiensis, gen. nov., sp. nov., a keratinophilic fungus from Australian soil

J. Cano*, M. Solé, L. B. Pitarch & J. Guarro

Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, Institut d'Estudis Avançats, Universitat Rovira i Virgili, 43201 – Reus, Tarragona, Spain

Abstract: Castanedomyces australiensis gen. nov., sp. nov., isolated from Australian soil, is described and illustrated. The outstanding characteristics of this new taxon are pilose, globose, non-ostiolate ascomata, with a membranous peridium and numerous seta-like appendages, and lenticular ascospores with a tuberculate wall and an equatorial crest. A comparative sequence analysis of the 18S rDNA gene of representative species of some morphologically related genera demonstrated a close relationship of Castanedomyces with Aphanoascus, another onygenalean genus which also possesses a membranous peridium, a feature found in only a few Onygenalean genera.

Pseudoamauroascus, a new genus of the Onygenales (Ascomycota)

J. Cano*, M. Solé, L.B. Pitarch & J. Guarro.

Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, Institut d’Estudis Avançats, Universitat Rovira i Virgili, 43201-Reus, Tarragona, Spain.

Abstract: The new genus and species Pseudoamauroascus australiensis, was isolated from Australian soil. This fungus is distinguished from other known taxa by producing the following combination of characters: white, spherical ascomata formed by a network of thin, hyaline hyphae indistinguishable from vegetative hyphae; oblate, brown ascospores ornamented with a reticulum of conspicuous and anastomosed crests; and a Malbranchea anamorph. Sequence analysis of the 18S rDNA and 5.8S rDNA genes supports the separation of this fungus from all taxa bearing some morphological similarity.

The genus Mallochia (Amauroascaceae)

S. Udagawa1 and S. Uchiyama2

1Department of Applied Biology and Chemistry, Tokyo University of Agriculture, Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan, 2Banyu Tsukuba Research Institute, Okubo, Tsukuba-shi, Ibaraki 300-2611, Japan

Abstract: Two new species, Mallochia endodonta and M. transmutans, isolated from Asian tropical soil, are described and illustrated. The generic concept is revised to include these taxa, the outstandingly distinctive characteristics of which include formation of brightly coloured, spherical, sometimes capitate ascomata without distinct peridial elements or formation of ascomata with a wall formed by a network of thin-walled hyphae (telaperidium), as well as production of one-celled, spherical, yellow or orange, spiny to warty ascospores. The type species, Mallochia echinulata is redescribed from a new collection.

Identification and phylogeny of Chrysosporium species using RFLP of the rDNA PCR-ITS region

P. Vidal and J. Guarro

Unitat de Microbiologia, Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina i Ciències de la Salut, c/ Sant Llorenç 21, 43201 Reus, and Institut d’Estudis Avançats, c/ de l’Escorxador s/n, 43003 Tarragona, Universitat Rovira i Virgili, Spain

Abstract: Identification of Chrysosporium spp. is difficult mainly because the genus contains many similar species and because members of some related genera are also similar in appearance. In order to obtain a reliable, objective identification method, restriction fragment length polymorphisms (RFLPs) of the PCR-amplified ribosomal internal transcribed spacer (ITS)1-5.8S-ITS2 DNA region from 139 strains belonging to 20 Chrysosporium species were studied using six endonucleases. A combination of three endonucleases, HaeIII, MspI, and HinFI, provided patterns that allowed the unequivocal identification of the species. Additionally, the polymorphism of the bands obtained in this analysis proved useful for quantitatively measuring phylogenetic distances among the fungi.


Two new species of Chrysosporium

P. Vidal1, M. Valmaseda2, M. Ángeles Vinuesa2 and J, Guarro1,*

1Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, 43201 Reus, Spain, 2SmithKline Beecham, Centro de Investigación Básica, 28760 Tres Cantos, Madrid, Spain

Abstract: Two new species of Chrysosporium, Chrysosporium submersum and Chrysosporium minutisporosum, each represented by numerous strains mainly isolated from river sediments of Catalunya, Spain, are described and illustrated. The former is characterized by large, clavate and verrucose conidia. The latter forms small, pyriform or subglobose, occasionally septate, verrucose conidia. Molecular analysis, based on sequences and restriction fragment length polymorphisms (RFLPs) of the ribosomal internal transcribed spacers (ITS) of these taxa and morphologically related species confirm these proposals.


A new species of Oidiodendron with gymnothecium-like sporodochia

M. Calduch, J. Gené*, J. Cano, & J. Guarro

Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, Institut d’Estudis Avançats, Universitat Rovira i Virgili, 43201-Reus, Tarragona, Spain

Abstract: The new species Oidiodendron myxotrichoides, isolated from litter in Spain, is described and illustrated. The most distinctive morphological features of this taxon are its conidiophores organized in globose to subglobose, dark brown sporodochia, similar to the ascomata (gymnothecia) of the ascomycete Myxotrichum, and its globose to broadly ellipsoidal, smooth arthroconidia. Analysis of its ribosomal gene’s internal transcribed spacer region sequences demonstrates its distinction from other species of Oidiodendron.