Dataset Information

DNA barcoding in Mucorales: an inventory of biodiversity.

ABSTRACT: The order Mucorales comprises predominantly fast-growing saprotrophic fungi, some of which are used for the fermentation of foodstuffs but it also includes species known to cause infections in patients with severe immune or metabolic impairments. To inventory biodiversity in Mucorales ITS barcodes of 668 strains in 203 taxa were generated covering more than two thirds of the recognised species. Using the ITS sequences, Molecular Operational Taxonomic Units were defined by a similarity threshold of 99 %. An LSU sequence was generated for each unit as well. Analysis of the LSU sequences revealed that conventional phenotypic classifications of the Mucoraceae are highly artificial. The LSU- and ITS-based trees suggest that characters, such as rhizoids and sporangiola, traditionally used in mucoralean taxonomy are plesiomorphic traits. The ITS region turned out to be an appropriate barcoding marker in Mucorales. It could be sequenced directly in 82 % of the strains and its variability was sufficient to resolve most of the morphospecies. Molecular identification turned out to be problematic only for the species complexes of Mucor circinelloides, M. flavus, M. piriformis and Zygorhynchus moelleri. As many as 12 possibly undescribed species were detected. Intraspecific variability differed widely among mucorealean species ranging from 0 % in Backusella circina to 13.3 % in Cunninghamella echinulata. A high proportion of clinical strains was included for molecular identification. Clinical isolates of Cunninghamella elegans were identified molecularly for the first time. As a result of the phylogenetic analyses several taxonomic and nomenclatural changes became necessary. The genus Backusella was emended to include all species with transitorily recurved sporangiophores. Since this matched molecular data all Mucor species possessing this character were transferred to Backusella. The genus Zygorhynchus was shown to be polyphyletic based on ITS and LSU data. Consequently, Zygorhynchus was abandoned and all species were reclassified in Mucor. Our phylogenetic analyses showed, furthermore, that all non-thermophilic Rhizomucor species belong to Mucor. Accordingly, Rhizomucor endophyticus was transferred to Mucor and Rhizomucor chlamydosporus was synonymised with Mucor indicus. Lecto-, epi- or neotypes were designated for several taxa.

SUBMITTER: Walther G

PROVIDER: S-EPMC3734965 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature

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DNA barcoding in Mucorales: an inventory of biodiversity.

Walther G G Pawłowska J J Alastruey-Izquierdo A A Wrzosek M M Rodriguez-Tudela J L JL Dolatabadi S S Chakrabarti A A de Hoog G S GS

Persoonia 20130304

The order Mucorales comprises predominantly fast-growing saprotrophic fungi, some of which are used for the fermentation of foodstuffs but it also includes species known to cause infections in patients with severe immune or metabolic impairments. To inventory biodiversity in Mucorales ITS barcodes of 668 strains in 203 taxa were generated covering more than two thirds of the recognised species. Using the ITS sequences, Molecular Operational Taxonomic Units were defined by a similarity threshold ...[more]

PMID: 24027345

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Project description:BackgroundThe hemi-metabolous aquatic order Plecoptera (stoneflies) constitutes an indispensable part of terrestrial and aquatic food webs due to their specific life cycle and habitat requirements. Stoneflies are considered one of the most sensitive groups to environmental changes in freshwater ecosystems and anthropogenic changes have caused range contraction of many species. Given the critical threat to stoneflies, the study of their distribution, morphological variability and genetic diversity should be one of the priorities in conservation biology. However, some aspects about stoneflies, especially a fully resolved phylogeny and their patterns of distribution are not well known. A study that includes comprehensive field research and combines morphological and molecular identification of stoneflies has not been conducted in Croatia so far. Thus, the major aim of this study was to regenerate a comprehensive and taxonomically well-curated DNA barcode database for Croatian stoneflies, to highlight the morphological variability obtained for several species and to elucidate results in light of recent taxonomy.MethodsA morphological examination of adult specimens was made using basic characteristics for distinguishing species: terminalia in males and females, head and pronotum patterns, penial morphology, and egg structures. DNA barcoding was applied to many specimens to help circumscribe known species, identify cryptic or yet undescribed species, and to construct a preliminary phylogeny for Croatian stoneflies.ResultsSequences (658 bp in length) of 74 morphospecies from all families present in Croatia were recovered from 87% of the analysed specimens (355 of 410), with one partial sequence of 605 bp in length for Capnopsis schilleri balcanica Zwick, 1984. A total of 84% morphological species could be unambiguously identified using COI sequences. Species delineation methods confirmed the existence of five deeply divergent genetic lineages, with monophyletic origin, which also differ morphologically from their congeners and represent distinct entities. BIN (Barcode Index Number) assignment and species delineation methods clustered COI sequences into different numbers of operational taxonomic units (OTUs). ASAP delimited 76 putative species and achieved a maximum match score with morphology (97%). ABGD resulted in 62 and mPTP in 61 OTUs, indicating a more conservative approach. Most BINs were congruent with traditionally recognized species. Deep intraspecific genetic divergences in some clades highlighted the need for taxonomic revision in several species-complexes and species-groups. Research has yielded the first molecular characterization of nine species, with most having restricted distributions and confirmed the existence of several species which had been declared extinct regionally.

Project description:The increasing growth of literature in biodiversity presents challenges to users who need to discover pertinent information in an efficient and timely manner. In response, text mining techniques offer solutions by facilitating the automated discovery of knowledge from large textual data. An important step in text mining is the recognition of concepts via their linguistic realisation, i.e., terms. However, a given concept may be referred to in text using various synonyms or term variants, making search systems likely to overlook documents mentioning less known variants, which are albeit relevant to a query term. Domain-specific terminological resources, which include term variants, synonyms and related terms, are thus important in supporting semantic search over large textual archives. This article describes the use of text mining methods for the automatic construction of a large-scale biodiversity term inventory. The inventory consists of names of species, amongst which naming variations are prevalent. We apply a number of distributional semantic techniques on all of the titles in the Biodiversity Heritage Library, to compute semantic similarity between species names and support the automated construction of the resource. With the construction of our biodiversity term inventory, we demonstrate that distributional semantic models are able to identify semantically similar names that are not yet recorded in existing taxonomies. Such methods can thus be used to update existing taxonomies semi-automatically by deriving semantically related taxonomic names from a text corpus and allowing expert curators to validate them. We also evaluate our inventory as a means to improve search by facilitating automatic query expansion. Specifically, we developed a visual search interface that suggests semantically related species names, which are available in our inventory but not always in other repositories, to incorporate into the search query. An assessment of the interface by domain experts reveals that our query expansion based on related names is useful for increasing the number of relevant documents retrieved. Its exploitation can benefit both users and developers of search engines and text mining applications.

Dataset Information

DNA barcoding in Mucorales: an inventory of biodiversity.

Publications

DNA barcoding in Mucorales: an inventory of biodiversity.

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