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Myriococcum everhartii. a, b Colony on natural substrate (scale = 500 µm, NYBG 927885; isotype). c Two mature sclerotia surrounded by a delicate sheath of hyphae (scale = 50 μm, NYBG 927882; isotype). d Detail of the peridium with cells with textura epidermoidea (scale = 20 μm, NYBG 927883). e Cross section of the sclerotium showing a distinct dark peridial layer (scale = 50 μm, NYBG 2480080; isotype). f Detail of inner cells and the peridium in cross section (scale = 20 μm, NYBG 2480080). g Detail of collapsed hyphae of the hyphal sheath (scale = 20 µm, NYBG 2480080)
Source publication
The genus Myriococcum was described based on a sterile fungus producing sclerotia. Misinterpretation of these structures resulted in the later addition of several largely unrelated species to this genus and controversy about its phylogenetic placement. The purpose of the study was to revise these species and elucidate their phylogenetic affinities....
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Citations
... Thermothelomyces myriococcoides CBS 389.93 (syn. Crassicarpon hotsonii, and Myriococcum thermophilum) is an ascomycete which was originated from the surface of heated compost in Switzerland [16,17]. It encodes 17 AA3s, a typical number for fungal organisms, among which four genes are predicted to encode enzymes belonging to family AA3_1 (Gene accession code: Myrth2p4_000359, Myrth2p4_001304, Myrth2p4_007444, and Myrth2p4_005287) [18]. ...
Background
The Carbohydrate-Active enZymes (CAZy) auxiliary activity family 3 (AA3) comprises flavin adenine dinucleotide-dependent (FAD) oxidoreductases from the glucose–methanol–choline (GMC) family, which play auxiliary roles in lignocellulose conversion. The AA3 subfamily 1 predominantly consists of cellobiose dehydrogenases (CDHs) that typically comprise a dehydrogenase domain, a cytochrome domain, and a carbohydrate-binding module from family 1 (CBM1).
Results
In this work, an AA3_1 gene from T. myriococcoides CBS 398.93 encoding only a GMC dehydrogenase domain was expressed in Aspergillus niger. Like previously characterized CDHs, this enzyme (TmXdhA) predominantly accepts linear saccharides with β-(1 → 4) linkage and targets the hydroxyl on the reducing anomeric carbon. TmXdhA was distinguished, however, by its preferential activity towards xylooligosaccharides over cellooligosaccharides. Amino acid sequence analysis showed that TmXdhA possesses a glutamine at the substrate-binding site rather than a threonine or serine that occupies this position in previously characterized CDHs, and structural models suggest the glutamine in TmXdhA could facilitate binding to pentose sugars.
Conclusions
The biochemical analysis of TmXdhA revealed a catalytic preference for xylooligosaccharide substrates. The modeled structure of TmXdhA provides a reference for the screening of oxidoreductases targeting xylooligosaccharides. We anticipate TmXdhA to be a good candidate for the conversion of xylooligosaccharides to added-value chemicals by its exceptional catalytic ability.
... A sole species of thermophilic fungus, Malbranchea cinnamomea, is found in the Onygenales (Morgenstern et al. 2012). Thermophilic Basidiomycota have been described by Straatsma et al. (1994) and Fergus (1971) but these species have either not been confirmed to be thermophilic or, as in the case of Myriococcum thermophilum, have been found to belong in the Ascomycota instead (Morgenstern et al. 2012;Koukol 2016). ...
Defined as fungi that grow better at 25 °C than at 45 °C, thermophilic fungi were discovered more than a century ago. Nevertheless, little is known about the natural roles and distribution of these organisms. Although common in “sun-heated soils” and other natural substrates they have most often been recovered from manmade composts, and one hypothesis suggests that they evolved as decomposers in natural compost. This hypothesis suggests that propagules found outside compost have been dispersed by wind, an idea that seems nearly impossible to reconcile with their high frequency and broad distribution. In this chapter we briefly review the biology, history, and evolution of thermophilic fungi. We also present new results from ongoing efforts to map the range of habitats from which thermophilic fungi can be obtained. We have isolated thermophilic fungi over small and large spatial scales. Our surveys have focused on soil, litter, and herbivore droppings sampled from diverse ecosystems (deserts, grasslands, and forests) across eight western states, Mexico and Canada—from southern deserts to alpine ecosystems in Colorado and Montana. Our results show that thermophiles can be isolated readily from all of these substrates at nearly every latitude and elevation. We observed that the success of recovering thermophilic fungi from soil decreases with increasing latitude. During this survey, we also discovered that several species of thermophilic fungi can survive storage in soil samples for several years at −80 °C.
... These features might correspond to its basal and isolated position within the Stephanosporaceae clade ( Lebel et al. 2015). On the other hand, the analysis of Koukol (2016) places Athelidium aurantiacum in the basal position of the Cristinia clade, therefore encompassing all smooth-spored species of the family in a single, well-supported clade. Major distinguishing characters of Athelidium from superficially similar athelioid genera seem to be the bright colour of the hymenium surface and somewhat constricted basidia. ...
The corticioid fungus Athelidium caucasicum (Stephanosporaceae) was found in central Europe (Czech Republic), being the second published record since the type collection was made. A description of macro- and micromorphological characters based on the recent collection is provided as well as notes on its ecology, variability and taxonomic position.
... Two unidentified basidiomycetous isolates have been shown to be able to grow at 45 °C in a study by Straatsma et al. 24 , but no additional studies on growth at different temperatures were conducted, making it impossible to classify the isolates as thermophilic or thermotolerant. The thermophilic species Myriococcum thermophilum previously listed as a mitosporic basidiomycete is now classified as Crassicarpon hotsonii (MB#816112) under Ascomycota 25 . ...
Thermophilic fungi can represent a rich source of industrially relevant enzymes. Here, 105 fungal strains capable of growing at 50 °C and pH 2.0 were isolated from compost and decaying plant matter. Maximum growth temperatures of the strains were in the range 50 °C to 60 °C. Sequencing of the internal transcribed spacer (ITS) regions indicated that 78 fungi belonged to 12 species of Ascomycota and 3 species of Zygomycota, while no fungus of Basidiomycota was detected. The remaining 27 strains could not be reliably assigned to any known species. Phylogenetically, they belonged to the genus Thielavia, but they represented 23 highly divergent genetic groups different from each other and from the closest known species by 12 to 152 nucleotides in the ITS region. Fungal secretomes of all 105 strains produced during growth on untreated rice straw were studied for lignocellulolytic activity at different pH and temperatures. The endoglucanase and xylanase activities differed substantially between the different species and strains, but in general, the enzymes produced by the novel Thielavia spp. strains exhibited both higher thermal stability and tolerance to acidic conditions. The study highlights the vast potential of an untapped diversity of thermophilic fungi in the tropics.
... & Everh.) Koukol (Koukol 2016). Species of Phialophora section Catenulatae with pigmented conidiophores have been accommodated in genera in three classes. ...
A new genus Rhopalophora is described for Phialophora clavispora, a lignicolous species formerly placed in Phialophora section Catenulatae that possesses pigmented conidiophores, phialides with a single conidiogenous locus that occasionally appear as schizophialides, and clavate, aseptate conidia arranged in chains or sometimes in heads. Sexual morphs are not known for this taxon. Phylogenetic analysis of DNA sequences from five loci (nucSSU, ITS, nucLSU, mitSSU, rpb1 and rpb2) of this and related fungi supports the introduction of a new family, Sclerococcaceae, for which we establish the order Sclerococcales. This order belongs to the new subclass Sclerococcomycetidae, a strongly supported clade within the Eurotiomycetes that is basal to a lineage containing the Chaetothyriomycetidae, Coryneliomycetidae and Eurotiomycetidae. Rhopalophora clavispora fits in this new family and is closely related to an isolate of Fusichalara minuta. The Sclerococcales also encompass marine, lignicolous species of Dactylospora, two species of the lichenicolous genus Sclerococcum, and a lineage comprised of strains from the digestive tracts of Neotropical wood-inhabiting beetles. We confirm that Dactylospora is polyphyletic; the phylogenetic placement of D. parasitica, the generic type, remains unknown.
Introduction. The Laboratory of Molecular Techniques applied to Phytoprotection (LTM), Crop Protection Research Center, Universidad de Costa Rica; receives agricultural, ornamental, and forest crops for the identification of microorganisms using molecular techniques. Objective. To identify pathogenic and non-pathogenic fungi, oomycetes, and protozoa in agricultural, ornamental, and forest crops in Costa Rica by molecular methods. Materials and methods. Between 2009 and 2018, plant parts (root, stem, leaves, fruits) and other materials such as water, substrate, and soil were received. A total of 805 isolates were obtained for identification of microorganisms by DNA extraction techniques, end-time and real-time PCR and sequencing using molecular markers. Results. The sequencing allowed the identification of a total of 154 species of fungi, 6 oomycetes, and 1 protozoa. Among the fungi identified, genera such as Fusarium predominated with fourteen different species, followed by Colletotrichum and Aspergillus with eleven species identified for each one. In the oomycetes, species of the genus Phytophthora prevailed, and within the protozoa the genus Plasmodiophora. In addition, the scientific references supporting the presence of the microorganisms identified in each particular crop have been included in the information. Conclusion. It was possible to identify by molecular techniques pathogenic and non-pathogenic fungi, oomycetes and protozoa species isolated from different agricultural, ornamental and forest crops in Costa Rica.
Background
The Carbohydrate-Active enZymes (CAZy) auxiliary activity family 3 (AA3) comprises flavin adenine dinucleotide-dependent (FAD) oxidoreductases from the glucose-methanol-choline (GMC) family, which play auxiliary roles in lignocellulose conversion. The AA3 subfamily 1 predominantly consists of cellobiose dehydrogenases (CDHs) that typically comprise a dehydrogenase domain, a cytochrome domain, and a carbohydrate-binding module from family 1 (CBM1).
Results
In this work, an AA3_1 gene from Thermothelomyces myriococcoides CBS 398.93 encoding only a GMC dehydrogenase domain was expressed in Aspergillus niger. Like previously characterized CDHs, this enzyme (TmXdhA) predominantly accepts linear saccharides with β-(1→4) linkage and targets the hydroxyl on the reducing anomeric carbon. TmXhdA was distinguished, however, by its preferential activity towards xylooligosaccharides over cellooligosaccharides. Amino acid sequence analysis showed that TmXdhA possesses a glutamine at the substrate-binding site rather than a threonine or serine that occupies this position in previously characterized CDHs, and structural models suggest the glutamine in TmXdhA could facilitate binding to pentose sugars.
Conclusions
The biochemical analysis of TmXdhA revealed a catalytic preference for xylooligosaccharide substrates. The modelled structure of TmXdhA provides a reference for the screening of oxidoreductases targeting xylooliogosaccharides. We anticipate TmXdhA to be a good candidate for the conversion of xylooligosaccharides to added-value chemicals by its exceptional catalytic ability.
Chaetomiaceae comprises phenotypically diverse species, which impact biotechnology, the indoor environment and human health. Recent studies showed that most of the traditionally defined genera in Chaetomiaceae are highly polyphyletic. Many of these morphology-based genera, such as Chaetomium , Thielavia and Humicola , have been redefined using multigene phylogenetic analysis combined with morphology; however, a comprehensive taxonomic overview of the family is lacking. In addition, the phylogenetic relationship of thermophilic Chaetomiaceae species with non-thermophilic taxa in the family is largely unclear due to limited taxon sampling in previous studies. In this study, we provide an up-to-date overview on the taxonomy and phylogeny of genera and species belonging to Chaetomiaceae , including an extensive taxon sampling of thermophiles. A multigene phylogenetic analysis based on the ITS (internal transcribed spacers 1 and 2 including the 5.8S nrDNA), LSU (D1/D2 domains of the 28S nrDNA), rpb2 (partial RNA polymerase II second largest subunit gene) and tub2 (β-tubulin gene) sequences was performed on 345 strains representing Chaetomiaceae and 58 strains of other families in Sordariales . Divergence times based on the multi-gene phylogeny were estimated as aid to determine the genera in the family. Genera were delimited following the criteria that a genus must be a statistically well-supported monophyletic clade in both the multigene phylogeny and molecular dating analysis, fall within a divergence time of over 27 million years ago, and be supported by ecological preference or phenotypic traits. Based on the results of the phylogeny and molecular dating analyses, combined with morphological characters and temperature-growth characteristics, 50 genera and 275 species are accepted in Chaetomiaceae . Among them, six new genera, six new species, 45 new combinations and three new names are proposed. The results demonstrate that the thermophilic species fall into seven genera ( Melanocarpus , Mycothermus , Remersonia , Thermocarpiscus gen. nov. , Thermochaetoides gen. nov. , Thermothelomyces and Thermothielavioides ). These genera cluster in six separate lineages, suggesting that thermophiles independently evolved at least six times within the family. A list of accepted genera and species in Chaetomiaceae , together with information on their MycoBank numbers, living ex-type strains and GenBank accession numbers to ITS, LSU, rpb2 and tub2 sequences is provided. Furthermore, we provide suggestions how to describe and identify Chaetomiaceae species.
The Basidiomycota constitutes a major phylum of the kingdom Fungi and is second in species numbers to the Ascomycota. The present work provides an overview of all validly published, currently used basidiomycete genera to date in a single document. An outline of all genera of Basidiomycota is provided, which includes 1928 currently used genera names, with 1263 synonyms, which are distributed in 241 families, 68 orders, 18 classes and four subphyla. We provide brief notes for each accepted genus including information on classification, number of accepted species, type species, life mode, habitat, distribution, and sequence information. Furthermore, three phylogenetic analyses with combined LSU, SSU, 5.8s, rpb1, rpb2, and ef1 datasets for the subphyla Agaricomycotina, Pucciniomycotina and Ustilaginomycotina are conducted, respectively. Divergence time estimates are provided to the family level with 632 species from 62 orders, 168 families and 605 genera. Our study indicates that the divergence times of the subphyla in Basidiomycota are 406–430 Mya, classes are 211–383 Mya, and orders are 99–323 Mya, which are largely consistent with previous studies. In this study, all phylogenetically supported families were dated, with the families of Agaricomycotina diverging from 27–178 Mya, Pucciniomycotina from 85–222 Mya, and Ustilaginomycotina from 79–177 Mya. Divergence times as additional criterion in ranking provide additional evidence to resolve taxonomic problems in the Basidiomycota taxonomic system, and also provide a better understanding of their phylogeny and evolution.
