63 research outputs found
Morphological and habitat differentiation between diploids and tetraploids of a Drakensberg near-endemic taxon, Rhodohypoxis baurii var. platypetala (Hypoxidaceae)
DATA AVAILABILITY STATEMENT: Flow cytometric fcs files for ploidy levels are available at https://osf.io/
e8k2g/?view_only=566e3f2f38194a42ae0c33f8c6e39559.Environmental factors may shape the spatial distribution of ploidy levels. Here,
we undertook a cytogeographical study of Rhodohypoxis baurii var. platypetala
(Hypoxidaceae), a Drakensberg near-endemic taxon. We addressed the following questions: (1) Are there mixed-ploidy populations or is each population represented by a single ploidy level? (2) Is there a pattern in the environmental
distribution of ploidy levels? (3) Are there specific environmental variables associated with each ploidy level locality? (4) Are plant traits similar or different within
and among ploidy levels across populations that experience different environmental factors? We measured leaf and flower traits of individuals that were sampled for flow cytometry from 17 populations across the KwaZulu-Natal and Free
State provinces in South Africa. We extracted daily climate data for 13 variables
and collected soil samples to evaluate pH and nutrient properties to characterize
the sampled populations to test for relationships with ploidy level distributions.
Twelve populations were found to contain only diploids, four populations contained only tetraploids, and only one population was ‘mixed ploidy’ (both diploid
and triploid individuals present). There was an overlap in the altitudinal range
of diploid and tetraploid populations, but diploids reached the highest altitudes
recorded for the current study. We also found that R.baurii var. platypetala occurs in acidic soils and that tetraploids occurred in soils with marginally higher
nitrogen and phosphorus than soils where diploids occur. Tetraploids generally
occurred in warmer conditions, in drier soils, and possessed broader leaves and
larger flowers than diploids. Our study suggests that soil factors and temperature
at a small (within localities) spatial scale likely shape ploidy level distributions in
the Drakensberg grasslands.The University of the Witwatersrand FriedelSellschop Award and the National Research Foundation.https://onlinelibrary.wiley.com/journal/14429993Plant Production and Soil SciencePlant ScienceSDG-15:Life on lan
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Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora
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.
Results
Forty-three distributional and phenological shifts consistent with past climatic change occur across the flora, and a comparable number of clades underwent adaptive changes in their flowering phenology (9 clades; half of the clades investigated) as underwent distributional shifts (12 clades; two thirds of the clades investigated). Of extant Cape angiosperm species, 14-41% have been contributed by lineages that show distributional shifts consistent with past climate change, yet a similar proportion (14-55%) arose from lineages that shifted flowering phenology.
Conclusions
Adaptive changes in ecology at the scale we uncover in the Cape and consistent with past climatic change have not been documented for other floras. Shifts in climate tolerance appear to have been more important in this flora than is currently appreciated, and lineages that underwent such shifts went on to contribute a high proportion of the flora's extant species diversity. That shifts in phenology, on an evolutionary timescale and on such a scale, have not yet been detected for other floras is likely a result of the method used; shifts in flowering phenology cannot be detected in the fossil record
Death of endemic Virgilia oroboides trees in South Africa caused by Diaporthe virgiliae sp. nov.
Numerous dead and dying individuals of the Western Cape endemic tree Virgilia oroboides (Fabaceae) were recently
observed within a South African national botanical garden. Root-rot fungi and fungi symbiotic with bark beetles (Curculionidae;
Scolytinae) from diseased trees were assessed for their respective roles in V. oroboides mortality. Disease
progression was also monitored over 1 year. Fungi were isolated from surface sterilized bark and root samples from
diseased trees and provisionally identified using data from the internal transcribed spacer regions (ITS1, ITS2), including
the 5 8S rRNA gene (ITS). Pathogenicity of selected fungi towards V. oroboides was tested under field conditions.
The pathogenicity of various bark beetle-associated Geosmithia (Hypocreales: Hypocreomycetidae) spp. from V. oroboides
were similarly assessed. The only fungus consistently isolated from lesions on the roots and bark of declining
V. oroboides, and never from healthy individuals, represented an undescribed Diaporthe (Diaporthales, Diaporthaceae)
species that was characterized using molecular (using data from the ITS marker and part of the b-tubulin gene, TUB),
cultural and morphological characters. It is an aggressive pathogen of V. oroboides, newly described here as Diaporthe
virgiliae sp. nov. Trees of all ages are susceptible to this pathogen with subsequent bark beetle attack of mature trees
only. All Geosmithia spp. from beetles and/or infected trees were nonpathogenic towards V. oroboides. Diaporthe virgiliae
caused a severe decline in the health of the monitored V. oroboides population over a period of only 1 year and
should be considered as a significant threat to these trees.DST/NRF Centre of Excellence in Tree Health Biotechnology (CHTB).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-3059hb201
Revision of the enigmatic South African Cryptolaryngini (Coleoptera, Curculionidae), with description of a new genus and twenty-two new species
SUPPLEMENTARY MATERIAL : Supp. file 1. Uncorrected p-distances between specimens based on COI and EF1.
https://DOI.org/10.5852/ejt.2023.877.2151.9151The weevil genus Cryptolarynx Van Schalkwyk, 1966 is endemic to the Northern and Western
Cape provinces of South Africa. The two previously known species of the genus, C. vitis (Marshall,
1957) and C. estriatus (Marshall, 1957), have an aberrant globular body and head shape, which has made
it difficult to place the genus into the classification systems of the Curculionoidea. This paper presents
the description of 21 new species of Cryptolarynx from South Africa (C. subglaber Haran sp. nov.,
C. squamulatus Haran sp. nov., C. muellerae Haran sp. nov., C. hirtulus Haran sp. nov., C. robustus
Haran sp. nov., C. namaquanus Haran sp. nov., C. carinatus Haran sp. nov., C. variabilis Haran sp. nov.,
C. pyrophilus Haran sp. nov., C. pilipes Haran sp. nov., C. armatus Haran sp. nov., C. falciformis Haran
sp. nov., C. oberprieleri Haran sp. nov., C. spinicornis Haran sp. nov., C. cederbergensis Haran sp. nov.,
C. homaroides Haran sp. nov., C. marshalli Haran sp. nov., C. endroedyi Haran sp. nov., C. oberlanderi
Haran sp. nov., C. san Haran sp. nov., and C. luteipennis Haran sp. nov.) and of one new genus and
species, Hadrocryptolarynx major Haran gen. et sp. nov., also from South Africa. A redescription of the genus Cryptolarynx is provided to incorporate the characters of the new species. The plant genus Oxalis
(Oxalidaceae) is recorded as larval host for several species of Cryptolarynx and for Hadrocryptolarynx
Haran gen. nov., as their larvae develop in the subterranean bulbs of members of the genus, and the
egg, larva and pupa of C. variabilis are described. The characters of the Cryptolarynx larva confirm that
Cryptolaryngini are an early-diverging group of Curculionidae, with a placement among taxa currently
classified in the subfamily Brachycerinae sensu lato, and although their exact taxonomic position
remains unresolved, some larval characters, and also pupal ones, suggest a close relationship between
Cryptolaryngini and Stenopelmus Schoenherr. Potential use of species of Cryptolarynx in the biological
control of weedy South African species of Oxalis is discussed.http;//www.europeanjournaloftaxonomy.euam2024Plant Production and Soil ScienceSDG-15:Life on lan
New species of Ophiostomatales from Scolytinae and Platypodinae beetles in the Cape Floristic Region, including the discovery of the sexual state of Raffaelea
Olea capensis and Rapanea melanophloeos
are important canopy trees in South African
Afromontane forests. Dying or recently dead individuals
of these trees are often infested by Scolytinae and
Platypodinae (Curculionidae) beetles. Fungi were
isolated from the surfaces of beetles emerging from
wood samples and their galleries. Based on micromorphological
and phylogenetic analyses, four fungal
species in the Ophiostomatales were isolated. These were Sporothrix pallida and three taxa here newly
described as Sporothrix aemulophila sp. nov., Raffaelea
vaginata sp. nov. and Raffaelea rapaneae sp. nov.
This study represents the first collection of S. pallida, a
species known from many environmental samples
from across the world, from Scolytinae beetles. S.
aemulophila sp. nov. is an associate of the ambrosia
beetle Xyleborinus aemulus. R. rapaneae sp. nov. and
R. vaginata sp. nov. were associated with a Lanurgus
sp. and Platypodinae beetle, respectively, and represent
the first Raffaelea spp. reported from the Cape
Floristic Region. Of significance is that R. vaginata
produced a sexual state analogous with those of Ophiostoma seticolle and O. deltoideosporum that
also grouped in our analyses in Raffaelea s. str., to date
considered an asexual genus. The morphology of the
ossiform ascospores and anamorphs of the three
species corresponded and the generic circumscription
of Raffaelea is thus emended to accommodate sexual
states. The two known species are provided with new
combinations, namely Raffaelea seticollis (R.W.
Davidson) Z.W. de Beer and T.A. Duong comb. nov.
and Raffaelea deltoideospora (Olchow. and J. Reid)
Z.W. de Beer and T.A. Duong comb. nov.DST/NRF Centre of Excellence in Tree Health Biotechnology (CHTB).http://link.springer.com/journal/104822016-10-30hb201
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Phylogenetic marker development for target enrichment from transcriptome and genome skim data: the pipeline and its application in southern African Oxalis (Oxalidaceae)
Phylogenetics benefits from using a large number of putatively independent nuclear loci and their combination with other sources of information, such as the plastid and mitochondrial genomes. To facilitate the selection of orthologous low‐copy nuclear (LCN) loci for phylogenetics in nonmodel organisms, we created an automated and interactive script to select hundreds of LCN loci by a comparison between transcriptome and genome skim data. We used our script to obtain LCN genes for southern African Oxalis (Oxalidaceae), a speciose plant lineage in the Greater Cape Floristic Region. This resulted in 1164 LCN genes greater than 600 bp. Using target enrichment combined with genome skimming (Hyb‐Seq), we obtained on average 1141 LCN loci, nearly the whole plastid genome and the nrDNA cistron from 23 southern African Oxalis species. Despite a wide range of gene trees, the phylogeny based on the LCN genes was very robust, as retrieved through various gene and species tree reconstruction methods as well as concatenation. Cytonuclear discordance was strong. This indicates that organellar phylogenies alone are unlikely to represent the species tree and stresses the utility of Hyb‐Seq in phylogenetics
Repression of Sex4 and Like Sex Four2 Orthologs in Potato Increases Tuber Starch Bound Phosphate With Concomitant Alterations in Starch Physical Properties
To examine the roles of starch phosphatases in potatoes, transgenic lines were produced where orthologs of SEX4 and LIKE SEX FOUR2 (LSF2) were repressed using RNAi constructs. Although repression of either SEX4 or LSF2 inhibited leaf starch degradation, it had no effect on cold-induced sweetening in tubers. Starch amounts were unchanged in the tubers, but the amount of phosphate bound to the starch was significantly increased in all the lines, with phosphate bound at the C6 position of the glucosyl units increased in lines repressed in StSEX4 and in the C3 position in lines repressed in StLSF2 expression. This was accompanied by a reduction in starch granule size and an alteration in the constituent glucan chain lengths within the starch molecule, although no obvious alteration in granule morphology was observed. Starch from the transgenic lines contained fewer chains with a degree of polymerization (DP) of less than 17 and more with a DP between 17 and 38. There were also changes in the physical properties of the starches. Rapid viscoanalysis demonstrated that both the holding strength and the final viscosity of the high phosphate starches were increased indicating that the starches have increased swelling power due to an enhanced capacity for hydration
IAPT chromosome data 39
No abstract available.https://onlinelibrary.wiley.com/journal/19968175hj2024Plant Production and Soil ScienceNon
Oxalis dreyerae (Oxalidaceae), a new species from South Africa
Oxalis dreyerae, a new species from the arid Richtersveld region of South Africa, is described. It is most similar to O. inconspicua from which it differs, among others, by having a larger plant body, larger and showier flowers with a broadly trumpet-shaped tube, much larger leaflets, petioles that are thicker than the peduncles, much larger lanceolate sepals and short, stubby teeth on the longer filaments. Its placement within the O. flava clade is supported by nrDNA ITS sequence evidence, which is also consistent with a close relationship to O. inconspicua. Oxalis dreyerae represents the eighth described species of Oxalis endemic to the arid Richtersveld of the Northern Cape, thus supporting the importance of the floristically diverse Gariep Centre of Endemism, of which the region forms a part.</jats:p
Symbiotic yeasts from the mycangium, larval gut and woody substrate of an African stag beetle Xiphodontus antilope (Coleoptera: Lucanidae)
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