160 research outputs found
An overview of the taxonomy, phylogeny, and typification of nectriaceous fungi in Cosmospora, Acremonium, Fusarium, Stilbella, and Volutella
A comprehensive phylogenetic reassessment of the ascomycete genus
Cosmospora (Hypocreales, Nectriaceae) is undertaken using
fresh isolates and historical strains, sequences of two protein encoding
genes, the second largest subunit of RNA polymerase II (rpb2), and a
new phylogenetic marker, the larger subunit of ATP citrate lyase
(acl1). The result is an extensive revision of taxonomic concepts,
typification, and nomenclatural details of many anamorph- and
teleomorph-typified genera of the Nectriaceae, most notably
Cosmospora and Fusarium. The combined phylogenetic analysis
shows that the present concept of Fusarium is not monophyletic and
that the genus divides into two large groups, one basal in the family, the
other terminal, separated by a large group of species classified in genera
such as Calonectria, Neonectria, and Volutella. All accepted
genera received high statistical support in the phylogenetic analyses.
Preliminary polythetic morphological descriptions are presented for each
genus, providing details of perithecia, micro- and/or macro-conidial
synanamorphs, cultural characters, and ecological traits. Eight species are
included in our restricted concept of Cosmospora, two of which have
previously documented teleomorphs and all of which have
Acremonium-like microconidial anamorphs. A key is provided to the
three anamorphic species recognised in Atractium, which is removed
from synonymy with Fusarium and epitypified for two macroconidial
synnematous species and one sporodochial species associated with waterlogged
wood. Dialonectria is recognised as distinct from Cosmospora
and two species with teleomorph, macroconidia and microconidia are accepted,
including the new species D. ullevolea. Seven species, one with a
known teleomorph, are classified in Fusicolla, formerly considered a
synonym of Fusarium including members of the F. aquaeductuum
and F. merismoides species complex, with several former varieties
raised to species rank. Originally a section of Nectria,
Macroconia is raised to generic rank for five species, all producing
a teleomorph and macroconidial anamorph. A new species of the
Verticillium-like anamorphic genus Mariannaea is described
as M. samuelsii. Microcera is recognised as distinct from
Fusarium and a key is included for four macroconidial species, that
are usually parasites of scale insects, two of them with teleomorphs. The four
accepted species of Stylonectria each produce a teleomorph and micro-
and macroconidial synanamorphs. The Volutella species sampled fall
into three clades. Pseudonectria is accepted for a perithecial and
sporodochial species that occurs on Buxus. Volutella s. str.
also includes perithecial and/or sporodochial species and is revised to
include a synnematous species formerly included in Stilbella. The
third Volutella-like clade remains unnamed. All fungi in this paper
are named using a single name system that gives priority to the oldest generic
names and species epithets, irrespective of whether they are originally based
on anamorph or teleomorph structures. The rationale behind this is
discussed
A systematic account of the genus Plagiostoma (Gnomoniaceae, Diaporthales) based on morphology, host-associations, and a four-gene phylogeny
Members of the genus Plagiostoma inhabit leaves, stems, twigs, and
branches of woody and herbaceous plants predominantly in the temperate
Northern Hemisphere. An account of all known species of Plagiostoma
including Cryptodiaporthe is presented based on analyses of
morphological, cultural, and DNA sequence data. Multigene phylogenetic
analyses of DNA sequences from four genes (β-tubulin, ITS,
rpb2, and tef1-α) revealed eight previously
undescribed phylogenetic species and an association between a clade composed
of 11 species of Plagiostoma and the host family Salicaceae.
In this paper these eight new species of Plagiostoma are described,
four species are redescribed, and four new combinations are proposed. A key to
the 25 accepted species of Plagiostoma based on host, shape, and size
of perithecia, perithecial arrangement in the host, and microscopic
characteristics of the asci and ascospores is provided. Disposition of
additional names in Cryptodiaporthe and Plagiostoma is also
discussed
Molecular phylogenetics of Pleosporales: Melanommataceae and Lophiostomataceae re-circumscribed (Pleosporomycetidae, Dothideomycetes, Ascomycota)
The classification of Pleosporales has posed major challenges due
to the lack of clear understanding of the importance of the morphological
characters used to distinguish between different groups in the order. This has
resulted in varied taxonomic treatments of many families in the group
including Melanommataceae and Lophiostomataceae. In this
study we employ two nuclear DNA gene markers, nuclear ribosomal large subunit
DNA and translation elongation factor 1-alpha in order to examine the
molecular phylogenetics of Pleosporales with strong emphasis on the
families Melanommataceae and Lophiostomataceae. Phylogenetic
analyses recovered Melanommataceae, Lophiostomataceae,
Hypsostromataceae, and a few others as strongly supported clades
within the Pleosporales. Melanommataceae as currently
circumscribed was found to be polyphyletic. The genera Byssosphaeria,
Melanomma, and Pseudotrichia were recovered within the family,
while others such as Ostropella and Xenolophium nested
outside in a weakly supported group along with Platystomum compressum
and Pseudotrichia guatopoensis that may correspond to the family
Platystomaceae. The genus Byssosphaeria was recovered as a
strongly supported group within the Melanommataceae while
Melanomma was weakly supported with unclear relationships among the
species. The genera Herpotrichia and Bertiella were also
found to belong in the Melanommataceae. Lophiostomataceae
occurs as a strongly supported group but its concept is here expanded to
include a new genus Misturatosphaeria that bears morphology
traditionally not known to occur in the family. The strongly supported clade
of Misturatosphaeria contains nine species that have gregarious,
papillate ascomata with lighter coloured apices and plugged ostioles and that
vary in ascospore morphology from 1- to 3-septate to muriform. Along with a
strongly supported Lophiostoma clade, also within the family are
Thyridaria macrostomoides based on new sequences from Kenyan
collections and Massariosphaeria triseptata, M. grandispora, Westerdykella
cylindrica and Preussia terricola based on GenBank sequences.
The family Hypsostromataceae was recovered as a strongly supported
monophyletic group nested within the Pleosporales
Pleosporales
One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae
Leaf-inhabiting genera of the Gnomoniaceae, Diaporthales
The Gnomoniaceae are characterised by ascomata that are generally
immersed, solitary, without a stroma, or aggregated with a rudimentary stroma,
in herbaceous plant material especially in leaves, twigs or stems, but also in
bark or wood. The ascomata are black, soft-textured, thin-walled, and
pseudoparenchymatous with one or more central or eccentric necks. The asci
usually have a distinct apical ring. The Gnomoniaceae includes
species having ascospores that are small, mostly less than 25 μm long,
although some are longer, and range in septation from non-septate to
one-septate, rarely multi-septate. Molecular studies of the
Gnomoniaceae suggest that the traditional classification of genera
based on characteristics of the ascomata such as position of the neck and
ascospores such as septation have resulted in genera that are not
monophyletic. In this paper the concepts of the leaf-inhabiting genera in the
Gnomoniaceae are reevaluated using multiple genes, specifically
nrLSU, translation elongation factor 1-alpha (tef1-α), and RNA
polymerase II second largest subunit (rpb2) for 64 isolates. ITS sequences
were generated for 322 isolates. Six genera of leaf-inhabiting
Gnomoniaceae are defined based on placement of their type species
within the multigene phylogeny. The new monotypic genus
Ambarignomonia is established for an unusual species, A.
petiolorum. A key to 59 species of leaf-inhabiting Gnomoniaceae is
presented and 22 species of Gnomoniaceae are described and
illustrated
Phacidium and Ceuthospora (Phacidiaceae) are congeneric: taxonomic and nomenclatural implications
The morphologically diverse genus Ceuthospora has traditionally been linked to Phacidium sexual morphs via association, though molecular or cultural data to confirm this relationship have been lacking. The aim of this study was thus to resolve the relationship of these two genera by generating nucleotide sequence data for three loci, ITS, LSU and RPB2. Based on these results, Ceuthospora is reduced to synonymy under the older generic name Phacidium. Phacidiaceae (currently Helotiales) is suggested to constitute a separate order, Phacidiales (Leotiomycetes), as sister to Helotiales, which is clearly paraphyletic. Phacidiaceae includes Bulgaria, and consequently the family Bulgariaceae becomes a synonym of Phacidiaceae. Several new combinations are introduced in Phacidium, along with two new species, P. pseudophacidioides, which occurs on Ilex and Chamaespartium in Europe, and Phacidium trichophori, which occurs on Trichophorum cespitosum subsp. germanicum in The Netherlands. The generic name Allantophomopsiella is introduced to accommodate A. pseudotsugae, a pathogen of conifers, while Gremmenia is resurrected to accommodate the snow-blight pathogens of conifers, G. abietis, G. infestans, and G. pini-cembrae
The Botryosphaeriaceae: genera and species known from culture
In this paper we give an account of the genera and species in the Botryosphaeriaceae. We consider morphological characters alone as inadequate to define genera or identify species, given the confusion it has repeatedly introduced in the past, their variation during development, and inevitable overlap as representation grows. Thus it seems likely that all of the older taxa linked to the Botryosphaeriaceae, and for which cultures or DNA sequence data are not available, cannot be linked to the species in this family that are known from culture. Such older taxa will have to be disregarded for future use unless they are epitypified. We therefore focus this paper on the 17 genera that can now be recognised phylogenetically, which concentrates on the species that are presently known from culture. Included is a historical overview of the family, the morphological features that define the genera and species and detailed descriptions of the 17 genera and 110 species. Keys to the genera and species are also provided. Phylogenetic relationships of the genera are given in a multi-locus tree based on combined SSU, ITS, LSU, EF1-α and β-tubulin sequences. The morphological descriptions are supplemented by phylogenetic trees (ITS alone or ITS + EF1-α) for the species in each genus.We would like to thank the curators of the numerous fungaria and Biological Resource Centres cited in this paper, for making specimens and cultures available for examination over the past 15 yr, without which this study would not have been possible. Part of this work was supported by Fundação para a Ciência e a Tecnologia (Portugal) through grant PEst-OE/BIA/UI0457/2011. Artur Alves and Alan Phillips were supported by the programme Ciência 2008, co-funded by the Human Potential Operational Programme (National Strategic Reference Framework 2007–2013) and the European Social Fund (EU).publishe
Lakeside View: Sociocultural Responses to Changing Water Levels of Lake Turkana, Kenya
Throughout the Holocene, Lake Turkana has been subject to drastic changes in lake levels and the subsistence strategies people employ to survive in this hot and arid region. In this paper, we reconstruct the position of the lake during the Holocene within a paleoclimatic context. Atmospheric forcing mechanisms are discussed in order to contextualize the broader landscape changes occurring in eastern Africa over the last 12,000 years. The Holocene is divided into five primary phases according to changes in the strand-plain evolution, paleoclimate, and human subsistence strategies practiced within the basin. Early Holocene fishing settlements occurred adjacent to high and relatively stable lake levels. A period of high-magnitude oscillations in lake levels ensued after 9,000 years BP and human settlements appear to have been located close to the margins of the lake. Aridification and a final regression in lake levels ensued after 5,000 years BP and human communities were generalized pastoralists-fishers-foragers. During the Late Holocene, lake levels may have dropped below their present position and subsistence strategies appear to have been flexible and occasionally specialized on animal pastoralism. Modern missionary and government outposts have encouraged the construction of permanent settlements in the region, which are heavily dependent on outside resources for their survival. Changes in the physical and cultural environments of the Lake Turkana region have been closely correlated, and understanding the relationship between the two variables remains a vital component of archaeological research
Ostäquatorial-Afrika zwischen Pangani und dem neuentdeckten Rudolf-See : Ergebnisse der Graf S. Telekischen Expedition 1887-88
von Ludwig v. Höhne
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