205 research outputs found
Phylogenetic diversity of insecticolous fusaria inferred from multilocus DNA sequence data and their molecular identification via FUSARIUM-ID and Fusarium MLST
We constructed several multilocus DNA sequence datasets to assess the phylogenetic diversity of insecticolous fusaria, especially focusing on those housed at the Agricultural Research Service Collection of Entomopathogenic Fungi (ARSEF), and to aid molecular identifications of unknowns via the FUSARIUM-ID and Fusarium MLST online databases and analysis packages. Analyses of a 190-taxon, two-locus dataset, which included 159 isolates from insects, indicated that: (i) insect-associated fusaria were nested within 10 species complexes spanning the phylogenetic breadth of Fusarium, (ii) novel, putatively unnamed insecticolous species were nested within 8/10 species complexes and (iii) Latin binomials could be applied with confidence to only 18/58 phylogenetically distinct fusaria associated with pest insects. Phylogenetic analyses of an 82-taxon, three-locus dataset nearly fully resolved evolutionary relationships among the 10 clades containing insecticolous fusaria. Multilocus typing of isolates within four species complexes identified surprisingly high genetic diversity in that 63/65 of the fusaria typed represented newly discovered haplotypes. The DNA sequence data, together with corrected ABI sequence chromatograms and alignments, have been uploaded to the following websites dedicated to identifying fusaria: FUSARIUM-ID (http://isolate.fusariumdb.org) a
The Common European Framework of Reference (CEFR) in Canada: A Research Agenda
This article proposes a research agenda for future inquiry into the use of the Common European Framework of Reference (CEFR) in the plurilingual Canadian context. Drawing on data collected from a research forum hosted by the Canadian Association of Second Language Teachers in 2014, as well as a detailed analysis of Canadian empirical studies and practice-based projects to date, the authors examine three areas of emphasis related to CEFR use: (a) K-12 education, including uses with learners; (b) initial teacher education, where additional language teacher candidates are situated as both learners and future teachers; and (c) postsecondary language learning contexts. Future research directions are proposed in consideration of how policymaking, language teaching and language learning are articulated across each of these three contexts. To conclude, a call is made for ongoing conversations encouraging stakeholders to consider how they might take up pan-Canadian interests when introducing various aspects of the CEFR and its related tools
Cladosporium leaf-blotch and stem rot of Paeonia spp. caused by Dichocladosporium chlorocephalum gen. nov.
Cladosporium chlorocephalum (= C. paeoniae) is a common,
widespread leaf-spotting hyphomycete of peony (Paeonia spp.),
characterised by having dimorphic conidiophores. During the season, one stage
of this fungus causes distinct, necrotic leaf-blotch symptoms on living leaves
of Paeonia spp. In late autumn, winter or after overwintering, a
second morphologically distinct conidiophore type occurs on dead, blackish,
rotting stems. Conspecificity of the two morphs, previously proposed on the
basis of observations in culture, was supported by DNA sequence data from the
ITS and LSU gene regions, using cultures obtained from leaf-blotch symptoms on
living leaves, as well as from dead stems of Paeonia spp. Sequence
data were identical, indicating a single species with two morphs. On account
of its distinct conidiogenous loci and conidial hila, as well as its
sequence-based phylogenetic position separate from the
Davidiella/Cladosporium clade, the peony fungus has to be excluded
from Cladosporium s. str., but still belongs to the
Davidiellaceae (Capnodiales). The leaf-blotching
(cladosporioid) morph of this fungus morphologically resembles species of
Fusicladium, but differs in having dimorphic fruiting, and is
phylogenetically distant from the Venturiaceae. The macronematous
(periconioid) morph resembles Metulocladosporiella (Chaetothyriales),
but lacks rhizoid conidiophore hyphae, and has 0-5-septate conidia. Hence,
C. chlorocephalum is assigned to the new genus
Dichocladosporium
Global distribution of two fungal pathogens threatening endangered sea turtles
This work was supported by grants of Ministerio de Ciencia e Innovación, Spain (CGL2009-10032, CGL2012-32934). J.M.S.R was supported by PhD fellowship of the CSIC (JAEPre 0901804). The Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council supported P.V.W. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Thanks Machalilla National Park in Ecuador, Pacuare Nature Reserve in Costa Rica, Foundations Natura 2000 in Cape Verde and Equilibrio Azul in Ecuador, Dr. Jesus Muñoz, Dr. Ian Bell, Dr. Juan Patiño for help and technical support during samplingPeer reviewedPublisher PD
Opportunistic, human-pathogenic species in the Herpotrichiellaceae are phenotypically similar to saprobic or phytopathogenic species in the Venturiaceae
Although morphologically similar, species of Cladophialophora
(Herpotrichiellaceae) were shown to be phylogenetically distinct from
Pseudocladosporium (Venturiaceae), which was revealed to be
synonymous with the older genus, Fusicladium. Other than being
associated with human disorders, species of Cladophialophora were
found to also be phytopathogenic, or to occur as saprobes on organic material,
or in water, fruit juices, or sports drinks, along with species of
Exophiala. Caproventuria and Metacoleroa were
confirmed to be synonyms of Venturia, which has Fusicladium
(= Pseudocladosporium) anamorphs. Apiosporina, based on
A. collinsii, clustered basal to the Venturia clade, and
appears to represent a further synonym. Several species with a
pseudocladosporium-like morphology in vitro represent a sister clade
to the Venturia clade, and are unrelated to Polyscytalum.
These taxa are newly described in Fusicladium, which is
morphologically close to Anungitea, a heterogeneous genus with
unknown phylogenetic affinity. In contrast to the
Herpotrichiellaceae, which were shown to produce numerous
synanamorphs in culture, species of the Venturiaceae were
morphologically and phylogenetically more uniform. Several new species and new
combinations were introduced in Cladophialophora, Cyphellophora
(Herpotrichiellaceae), Exophiala, Fusicladium, Venturia
(Venturiaceae), and Cylindrosympodium (incertae
sedis)
Habitat and Host Indicate Lineage Identity in Colletotrichum gloeosporioides s.l. from Wild and Agricultural Landscapes in North America
Understanding the factors that drive the evolution of pathogenic fungi is central to revealing the mechanisms of virulence and host preference, as well as developing effective disease control measures. Prerequisite to these pursuits is the accurate delimitation of species boundaries. Colletotrichum gloeosporioides s.l. is a species complex of plant pathogens and endophytic fungi for which reliable species recognition has only recently become possible through a multi-locus phylogenetic approach. By adopting an intensive regional sampling strategy encompassing multiple hosts within and beyond agricultural zones associated with cranberry (Vaccinium macrocarpon Aiton), we have integrated North America strains of Colletotrichum gloeosporioides s.l. from these habitats into a broader phylogenetic framework. We delimit species on the basis of genealogical concordance phylogenetic species recognition (GCPSR) and quantitatively assess the monophyly of delimited species at each of four nuclear loci and in the combined data set with the genealogical sorting index (gsi). Our analysis resolved two principal lineages within the species complex. Strains isolated from cranberry and sympatric host plants are distributed across both of these lineages and belong to seven distinct species or terminal clades. Strains isolated from V. macrocarpon in commercial cranberry beds belong to four species, three of which are described here as new. Another species, C. rhexiae Ellis & Everh., is epitypified. Intensive regional sampling has revealed a combination of factors, including the host species from which a strain has been isolated, the host organ of origin, and the habitat of the host species, as useful indicators of species identity in the sampled regions. We have identified three broadly distributed temperate species, C. fructivorum, C. rhexiae, and C. nupharicola, that could be useful for understanding the microevolutionary forces that may lead to species divergence in this important complex of endophytes and plant pathogens
Optical Light Curves of the Type Ia Supernovae 1990N and 1991T
We present UBVRI light curves for the bright Type Ia supernovae SN 1990N in
NGC 4639 and SN 1991T in NGC 4527 based on photometry gathered in the course of
the Calan/Tololo supernova program. Both objects have well-sampled light curves
starting several days before maximum light and spanning well through the
exponential tail. These data supercede the preliminary photometry published by
Leibundgut et al (1991) and Phillips et al (1992). The host galaxies for these
supernovae have (or will have) accurate distances based on the Cepheid
period-luminosity relationship. The photometric data in this paper provide
template curves for the study of general population of Type Ia supernova and
accurate photometric indices needed for the Cepheid-supernova distance scale.Comment: AAS LaTeX, 30 pages, 10 figures, to appear in the Jan 1998
Astronomical Journal. Figs 1 and 2 (finding charts) not include
Factors That Affect Large Subunit Ribosomal DNA Amplicon Sequencing Studies of Fungal Communities: Classification Method, Primer Choice, and Error
Nuclear large subunit ribosomal DNA is widely used in fungal phylogenetics and to an increasing extent also amplicon-based environmental sequencing. The relatively short reads produced by next-generation sequencing, however, makes primer choice and sequence error important variables for obtaining accurate taxonomic classifications. In this simulation study we tested the performance of three classification methods: 1) a similarity-based method (BLAST + Metagenomic Analyzer, MEGAN); 2) a composition-based method (Ribosomal Database Project naïve Bayesian classifier, NBC); and, 3) a phylogeny-based method (Statistical Assignment Package, SAP). We also tested the effects of sequence length, primer choice, and sequence error on classification accuracy and perceived community composition. Using a leave-one-out cross validation approach, results for classifications to the genus rank were as follows: BLAST + MEGAN had the lowest error rate and was particularly robust to sequence error; SAP accuracy was highest when long LSU query sequences were classified; and, NBC runs significantly faster than the other tested methods. All methods performed poorly with the shortest 50–100 bp sequences. Increasing simulated sequence error reduced classification accuracy. Community shifts were detected due to sequence error and primer selection even though there was no change in the underlying community composition. Short read datasets from individual primers, as well as pooled datasets, appear to only approximate the true community composition. We hope this work informs investigators of some of the factors that affect the quality and interpretation of their environmental gene surveys
Comparative genomics of Beauveria bassiana: uncovering signatures of virulence against mosquitoes
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