Publications by authors named "Dirk U Bellstedt"

Article Synopsis
  • Current estimates show that a significant number of vascular plant species, especially narrow-range woody plants in biodiversity hotspots, are at high risk of extinction, particularly in the Cape Floristic Region (CFR) of South Africa.
  • The genus under study has 851 species, with nearly 200 already classified as threatened and many others lacking sufficient data for assessment.
  • The research suggests using phylogenetic diversity and threat status to identify the most endangered species for conservation, focusing on 39 evolutionarily distinct species, mainly from the CFR, while highlighting knowledge gaps for further assessment.
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The megagenus L. (Ericaceae), as it is recognised today, includes 851 species of evergreen shrubs or small trees, the majority of which are endemic to the Cape Floristic Region of South Africa. From the first descriptions in Linnaeus's , a succession of authors ascribed the steadily accumulating numbers of known species to various of a total of 72 different genera.

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A new seasonal killifish of the genus Nothobranchius is described from the Montepuez River system in northern Mozambique. The new species, Nothobranchius balamaensis Bragana Chakona, is differentiated from congeners by its characteristic colour pattern and molecular data further support its taxonomic distinctiveness. Phylogenetic results based on two mitochondrial and three nuclear genes confirms N.

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This paper reports a phylogeny of the African killifishes (Genus Nothobranchius, Order Cyprinodontiformes) informed by five genetic markers (three nuclear, two mitochondrial) of 80 taxa (seven undescribed and 73 of the 92 recognized species). These short-lived annual fishes occupy seasonally wet habitats in central and eastern Africa, and their distribution coincides largely with the East African Rift System (EARS). The fossil dates of sister clades used to constrain a chronometric tree of all sampled Nothobranchius recovered the origin of the genus at ~13.

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Phylogenetic relationships within the Orchideae sensu Pridgeon et al, remain one of the biggest unresolved issues in our understanding of the taxonomy of the orchids. Members of the Orchideae are numerous and widespread in Africa but remain poorly represented in phylogenetic research. In this study we included a broad sampling of African taxa for which we sequenced three plastid (rbcl, matK and trnL + trnL-F) and two nuclear regions (ITS and 18S).

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The Cape Floristic Region (CFR) is a biodiversity hotspot, recognized globally for its unusually high levels of endemism. The origins of this biodiversity are a long-standing topic of research. The largest "Cape clade," , radiated dramatically in the CFR, its ca.

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Background: The coincidence of long distance dispersal (LDD) and biome shift is assumed to be the result of a multifaceted interplay between geographical distance and ecological suitability of source and sink areas. Here, we test the influence of these factors on the dispersal history of the flowering plant genus Erica (Ericaceae) across the Afrotemperate. We quantify similarity of Erica climate niches per biogeographic area using direct observations of species, and test various colonisation scenarios while estimating ancestral areas for the Erica clade using parametric biogeographic model testing.

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In ostriches, the population densities resulting from intensive rearing increases susceptibility to pathogens such as mycoplasmas. In addition to good management practices, vaccination offers an attractive alternative for controlling mycoplasma infections in food animals, instead of using antibiotics, which often leave unacceptable residues. The use of live attenuated vaccines, however, carry the concern of reversion to virulence or genetic recombination with field strains.

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Targeted high-throughput sequencing using hybrid-enrichment offers a promising source of data for inferring multiple, meaningfully resolved, independent gene trees suitable to address challenging phylogenetic problems in species complexes and rapid radiations. The targets in question can either be adopted directly from more or less universal tools, or custom made for particular clades at considerably greater effort. We applied custom made scripts to select sets of homologous sequence markers from transcriptome and WGS data for use in the flowering plant genus (Ericaceae).

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The dry biomes of southern Africa (Desert, Nama Karoo and Succulent Karoo) are home to a rich and diverse xerophytic flora. This flora includes two morphologically diverse clades of Zygophyllaceae, Tetraena and Roepera (Zygophylloideae), which inhabit some of the most arid habitats in the region. Using a plastid phylogeny of Zygophylloideae we assess whether the evolution of putatively adaptive traits (leaf shape, vasculature, mode of water storage and photosynthetic type: C3 versus C4) coincides with the successful colonisation of environments with different drought regimes within southern Africa.

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Oceans, or other wide expanses of inhospitable environment, interrupt present day distributions of many plant groups. Using molecular dating techniques, generally incorporating fossil evidence, we can estimate when such distributions originated. Numerous dating analyses have recently precipitated a paradigm shift in the general explanations for the phenomenon, away from older geological causes, such as continental drift, in favour of more recent, long-distance dispersal (LDD).

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The lack of an annotated oppA gene as part of many oligopeptide permease (opp) operons has questioned the necessity of the oligopeptide-binding domain (OppA) as a part of the Opp transport system in mycoplasmas. This study investigated the occurrence of an oppA gene as part of the oppBCDF operon in 42 mycoplasma genomes. Except for hemoplasma, all mycoplasmas were found to possess one or more copies of the oppBCDF operon and with the help of similarity searches their oppA genes could be identified.

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The inference of phylogenetic relationships is often complicated by differing evolutionary histories of independently-inherited markers. The causes of the resulting gene tree incongruence can be challenging to identify, often relying on coalescent simulations dependent on unverifiable assumptions. We investigated alternative techniques using the South African rosulate species of Streptocarpus as a study group.

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Potato virus Y (PVY) is a major agricultural disease that reduces crop yields worldwide. Different strains of PVY are associated with differing degrees of pathogenicity, of which the most common and economically important are known to be recombinant. We need to know the evolutionary origins of pathogens to prevent further escalations of diseases, but putatively reticulate genealogies are challenging to reconstruct with standard phylogenetic approaches.

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Potato virus Y (PVY) is an important plant pathogen, whose host range includes economically important crops such as potato, tobacco, tomato, and pepper. PVY presents three main strains (PVY(O), PVY(N) and PVY(C)) and several recombinant forms. PVY has a worldwide distribution, yet the mechanisms that promote and maintain its population structure and genetic diversity are still unclear.

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Acacia saligna is a species complex that has become invasive in a number of countries worldwide where it has caused substantial environmental and economic impacts. Understanding genetic and other factors contributing to its success may allow managers to limit future invasions of closely related species. We used three molecular markers to compare the introduced range (South Africa) to the native range (Western Australia).

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Erica L. is the largest of the 'Cape' clades that together comprise around half of the disproportionately high species richness of the Cape Floristic Region (CFR) of South Africa. Around 840 species of Erica are currently recognised, C.

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It is widely recognized that we are entering an extinction event on a scale approaching the mass extinctions seen in the fossil record. Present-day rates of extinction are estimated to be several orders of magnitude greater than background rates and are projected to increase further if current trends continue. In vertebrates, species traits, such as body size, fecundity, and geographic range, are important predictors of vulnerability.

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Premise Of The Study: We present a rapid and inexpensive alternative to DNA isolation for polymerase chain reaction (PCR) amplification from plants. •

Methods And Results: The method involves direct PCR amplification from material macerated in one buffer, followed by dilution and incubation in a second buffer. We describe the procedure and demonstrate its application for nuclear and plastid DNA amplification across a broad range of vascular plants.

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Background: The best documented survival responses of organisms to past climate change on short (glacial-interglacial) timescales are distributional shifts. Despite ample evidence on such timescales for local adaptations of populations at specific sites, the long-term impacts of such changes on evolutionary significant units in response to past climatic change have been little documented. Here we use phylogenies to reconstruct changes in distribution and flowering ecology of the Cape flora--South Africa's biodiversity hotspot--through a period of past (Neogene and Quaternary) changes in the seasonality of rainfall over a timescale of several million years.

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Fire may have been a crucial component in the evolution of the Cape flora of South Africa, a region characterized by outstanding levels of species richness and endemism. However, there is, to date, no critical assessment of the age of the modern fire regime in this biome. Here, we exploit the presence of two obligate post-fire flowering clades in the orchid genus Disa, in conjunction with a robust, well-sampled and dated molecular phylogeny, to estimate the age by which fire must have been present.

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The coat protein (CP) gene of 75 South African Potato virus Y (PVY) isolates was amplified using reverse-transcriptase polymerase chain reaction (RT-PCR). The resulting cDNA products were cloned and sequenced. These sequences were used to identify the strains to which the isolates belonged.

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Grapevine fanleaf virus (GFLV) is responsible for severe fanleaf degeneration in grapevines of all major wine producing regions of the world, including South Africa. In order to successfully control the spread of the virus, specific and reliable diagnostic assays are necessary. The genetic variability of 12 GFLV isolates recovered from naturally infected grapevine plants in the Western Cape region of South Africa were characterised.

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Outbreaks of bacterial wilt caused by Ralstonia solanacearum in South Africa in the 1980s necessitated the development of a sensitive assay for its detection. In this chapter, the development of an enzyme-linked immunosorbent assay (ELISA) for the detection of Ralstonia solanacearum including antibody production, the ELISA method itself, potato sample preparation for testing, ELISA result validation and interpretation, and confirmation of infection are discussed. Data showing the drop in the Ralstonia solanacearum infection rate, after testing was implemented, are presented and shows how the use of this method has brought the disease under control in South Africa.

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Like island-endemic taxa, whose origins are expected to postdate the appearance of the islands on which they occur, biome-endemic taxa should be younger than the biomes to which they are endemic. Accordingly, the ages of biome-endemic lineages may offer insights into biome history. In this study, we used the ages of multiple lineages to explore the origin and diversification of two southern African biomes whose remarkable floristic richness and endemism has identified them as global biodiversity hotspots (succulent karoo and fynbos).

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