ITS secondary structure reconstruction to resolve taxonomy and phylogeny of the Betula L. genus
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ABSTRACT:
SUBMITTER: Tarieiev A
PROVIDER: S-EPMC7996101 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Using a global set of isolates and a phylogenetic approach employing DNA sequence data from five genes (?-tubulin, histone H3, internal transcribed spacer region, 28S large subunit region and translation elongation factor 1-?), the taxonomic status of the genus Gliocladiopsis (Glionectria) (Hypocreales, Nectriaceae) was re-evaluated. Gliocladiopsis sagariensis is reinstated as type species for the genus, which proved to be distinct from its former synonym, G. tenuis. The purported teleomorph state of G. tenuis, Glionectria tenuis, is shown to be distinct based on morphological comparisons supported by phylogenetic inference, and is provided with a new name, Gliocladiopsis pseudotenuis. A further four species, mostly isolated from soil, are newly described, namely G. curvata (New Zealand, Ecuador and Indonesia), G. elghollii (USA), G. indonesiensis (Indonesia) and G. mexicana (Mexico). Although species of Gliocladiopsis are frequently isolated from roots of diseased plants or plant litter in soil, little is presently known of their ecology, or potential role as plant pathogens.
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Project description:Species in the genus Gliocephalotrichum (= Leuconectria) (Hypocreales, Nectriaceae) are soilborne fungi, associated with post-harvest fruit spoilage of several important tropical fruit crops. Contemporary taxonomic studies of these fungi have relied on morphology and DNA sequence comparisons of the internal transcribed spacer region of the nuclear rDNA (ITS) and the β-tubulin gene regions. Employing DNA sequence data from four loci (β-tubulin, histone H3, ITS, and translation elongation factor 1-alpha) and morphological comparisons, the taxonomic status of the genus Gliocephalotrichum was re-evaluated. As a result five species are newly described, namely G. humicola (Taiwan, soil), G. mexicanum (rambutan fruit from Mexico), G. nephelii (rambutan fruit from Guatemala), G. queenslandicum (Australia, endophytic isolations) and G. simmonsii (rambutan fruit from Guatemala). Although species of Gliocephalotrichum are generally not regarded as important plant pathogens, their ability to cause post-harvest fruit rot could have an impact on fruit export and storage.
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Project description:Background and aimsBetula L. (birch) is a genus of approx. 60 species, subspecies or varieties with a wide distribution in the northern hemisphere, of ecological and economic importance. A new classification of Betula has recently been proposed based on morphological characters. This classification differs somewhat from previously published molecular phylogenies, which may be due to factors such as convergent evolution, hybridization, incomplete taxon sampling or misidentification of samples. While chromosome counts have been made for many species, few have had their genome size measured. The aim of this study is to produce a new phylogenetic and genome size analysis of the genus.MethodsInternal transcribed spacer (ITS) regions of nuclear ribosomal DNA were sequenced for 76 Betula samples verified by taxonomic experts, representing approx. 60 taxa, of which approx. 24 taxa have not been included in previous phylogenetic analyses. A further 49 samples from other collections were also sequenced, and 108 ITS sequences were downloaded from GenBank. Phylogenetic trees were built for these sequences. The genome sizes of 103 accessions representing nearly all described species were estimated using flow cytometry.Key resultsAs expected for a gene tree of a genus where hybridization and allopolyploidy occur, the ITS tree shows clustering, but not resolved monophyly, for the morphological subgenera recently proposed. Most sections show some clustering, but species of the dwarf section Apterocaryon are unusually scattered. Betula corylifolia (subgenus Nipponobetula) unexpectedly clusters with species of subgenus Aspera Unexpected placements are also found for B. maximowicziana, B. bomiensis, B. nigra and B. grossa Biogeographical disjunctions were found within Betula between Europe and North America, and also disjunctions between North-east and South-west Asia. The 2C-values for Betula ranged from 0·88 to 5·33 pg, and polyploids are scattered widely throughout the ITS phylogeny. Species with large genomes tend to have narrow ranges.ConclusionsBetula grossa may have formed via allopolyploidization between parents in subgenus Betula and subgenus Aspera. Betula bomiensis may also be a wide allopolyploid. Betula corylifolia may be a parental species of allopolyploids in the subsection Chinenses Placements of B. maximowicziana, B. michauxii and B. nigra need further investigation. This analysis, in line with previous studies, suggests that section Apterocaryon is not monophyletic and thus dwarfism has evolved repeatedly in different lineages of Betula Polyploidization has occurred many times independently in the evolution of Betula.
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Project description:The genus Tubakia is revised on the basis of morphological and phylogenetic data. The phylogenetic affinity of Tubakia to the family Melanconiellaceae (Diaporthales) was recently postulated, but new analyses based on sequences retrieved from material of the type species of Tubakia, T. dryina, support a family of its own, viz. Tubakiaceae fam. nov. Our phylogenetic analyses revealed the heterogeneity of Tubakia s. lat. which is divided into several genera, viz., Tubakia s. str., Apiognomonioides gen. nov. (type species: Apiognomonioides supraseptata), Involutiscutellula gen. nov. (type species: Involutiscutellula rubra), Oblongisporothyrium gen. nov. (type species: Oblongisporothyrium castanopsidis), Paratubakia gen. nov. (type species: Paratubakia subglobosa), Racheliella gen. nov. (type species: Racheliella wingfieldiana sp. nov.), Saprothyrium gen. nov. (type species: Saprothyrium thailandense) and Sphaerosporithyrium gen. nov. (type species: Sphaerosporithyrium mexicanum sp. nov.). Greeneria saprophytica is phylogenetically closely allied to Racheliella wingfieldiana and is therefore reallocated to Racheliella. Particular emphasis is laid on a revision and phylogenetic analyses of Tubakia species described from Japan and North America. Almost all North American collections of this genus were previously referred to as T. dryina s. lat., which is, however, a heterogeneous complex. Several new North American species have recently been described. The new species Sphaerosporithyrium mexicanum, Tubakia melnikiana and T. sierrafriensis, causing leaf spots on several oak species found in the North-Central Mexican state Aguascalientes and the North-Eastern Mexican state Nuevo León, are described, illustrated, and compared with similar species. Several additional new species are introduced, including Tubakia californica based on Californian collections on various species of the genera Chrysolepis, Notholithocarpus and Quercus, and T. dryinoides, T. oblongispora, T. paradryinoides, and Paratubakia subglobosoides described on the basis of Japanese collections. Tubakia suttoniana nom. nov., based on Dicarpella dryina, is a species closely allied to T. californica and currently only known from Europe. Tubakia dryina, type species of Tubakia, is epitypified, and the phylogenetic position and circumscription of Tubakia are clarified. A revised, supplemented key to the species of Tubakia and allied genera on the basis of conidiomata is provided.
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Project description:The taxonomy of the genus Hormomyces, typified by Hormomyces aurantiacus, which based on circumstantial evidence was long assumed to be the hyphomycetous asexual morph of Tremella mesenterica (Tremellales, Tremellomycetes) or occasionally Dacrymyces (Dacrymycetales, Dacrymycetes), is revised. Phylogenies based on the three nuc rDNA markers [internal transcribed spacers (ITS), 28S large ribosomal subunit nrDNA (28S) and 18S small ribosomal subunit nrDNA (18S)], based on cultures from Canada and the United States, suggest that the genus is synonymous with Tulasnella (Cantharellales, Agaricomycetes) rather than Tremella or Dacrymyces. Morphological studies of 38 fungarium specimens of Hormomyces, including the type specimens of H. callorioides, H. fragiformis, H. paridiphilus and H. peniophorae and examination of the protologues of H. abieticola, H. aurantiacus and H. pezizoideus suggest that H. callorioides and H. fragiformis are conspecific with H. aurantiacus while the remaining species are unlikely to be related to Tulasnella. The conidial chains produced by H. aurantiacus are similar to monilioid cells of asexual morphs of Tulasnella species formerly referred to the genus Epulorhiza. The new combination Tulasnella aurantiaca is proposed and the species is redescribed, illustrated and compared with similar fungi. The ecological niche of T. aurantiaca and its possible relationship to orchid root endophytes is discussed. A key to asexual genera with similar conidium ontogeny to T. aurantiaca is provided. Citation: Mack J, Assabgui RA, Seifert KA (2021). Taxonomy and phylogeny of the basidiomycetous hyphomycete genus Hormomyces. Fungal Systematics and Evolution 7: 177-196. doi: 10.3114/fuse.2021.07.09.
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Project description:The order Thermoanaerobacterales currently consists of fermentative anaerobic bacteria, including the genus Caldicellulosiruptor. Caldicellulosiruptor are represented by thirteen species; all, but one, have closed genome sequences. Interest in these extreme thermophiles has been motivated not only by their high optimal growth temperatures (≥70°C), but also by their ability to hydrolyze polysaccharides including, for some species, both xylan and microcrystalline cellulose. Caldicellulosiruptor species have been isolated from geographically diverse thermal terrestrial environments located in New Zealand, China, Russia, Iceland and North America. Evidence of their presence in other terrestrial locations is apparent from metagenomic signatures, including volcanic ash in permafrost. Here, phylogeny and taxonomy of the genus Caldicellulosiruptor was re-examined in light of new genome sequences. Based on genome analysis of 15 strains, a new order, Caldicellulosiruptorales, is proposed containing the family Caldicellulosiruptoraceae, consisting of two genera, Caldicellulosiruptor and Anaerocellum. Furthermore, the order Thermoanaerobacterales also was re-assessed, using 91 genome-sequenced strains, and should now include the family Thermoanaerobacteraceae containing the genera Thermoanaerobacter, Thermoanaerobacterium, Caldanaerobacter, the family Caldanaerobiaceae containing the genus Caldanaerobius, and the family Calorimonaceae containing the genus Calorimonas. A main outcome of ANI/AAI analysis indicates the need to reclassify several previously designated species in the Thermoanaerobacterales and Caldicellulosiruptorales by condensing them into strains of single species. Comparative genomics of carbohydrate-active enzyme inventories suggested differentiating phenotypic features, even among strains of the same species, reflecting available nutrients and ecological roles in their native biotopes.
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