Phylogenetic Implications of a Unique 5.8S nrDNA Insertion in Cyperaceae

The purpose of this study was to assess the phylogenetic utility of a large insertion (3 bp) in the 5.8S gene of nuclear ribosomal DNA (nrDNA) in Cyperaceae and selected Juncaceae. This was done by reconstructing the character evolution of the insertion on a phylogeny derived from rbcL sequences. Results suggest that the insertion was gained once at the base of Cyperaceae followed by multiple losses in its most-derived taxa. Despite several homoplastic losses (CI = 0.20), the pattern of insertion loss (RI = 0.88), and base pair variation within the insertion were useful for defining sedge clades at various taxonomic levels. For example, whereas a loss of the insertion appeared to characterize a major terminal clade within Cyperaceae, both an insertion loss and sequence variation were consistent with infrageneric clades previously discovered in an ITS phylogeny of Eleocharis. The presence/absence of the insertion also supported previous conclusions based on morphological and molecular data that tribe Scirpeae and Scirpus s.l. are polyphyletic. In the context of our current understanding of Cyperaceae relationships, evolutionary patterns related to this insertion provide additional support for groups defined in prior phylogenetic analyses. The present analysis also suggests that the controversial position of Oxychloe andina (Juncaceae) in previous rbcL analyses, as sister to Cyperaceae (Y12978) or as nested within Cyperaceae (U49222), is due to the fact that Y12978 is a Juncaceae/Cyperaceae chimera, whereas U49222 is the sequence of a Cyperaceae contaminant. When U49222 is excluded from analyses and the Cyperaceae portion of Y12978 is removed, Juncaceae and Cyperaceae are monophyletic with Oxychloe positioned within a Juncaceae clade of single-flowered genera

Revision of the Afro-Madagascan genus Costularia (Schoeneae, Cyperaceae) : infrageneric relationships and species delimitation

A recent molecular phylogenetic study revealed four distinct evolutionary lineages in the genus Costularia s.l. (Schoeneae, Cyperaceae, Poales). Two lineages are part of the Oreobolus Glade of tribe Schoeneae: the first being a much-reduced genus Costularia s.s., and the second a lineage endemic to New Caledonia for which a new genus Chamaedendron was erected. The other two lineages were shown to be part of the Tricostularia Glade of tribe Schoeneae. Based on morphological and molecular data, the genus Costularia is here redelimited to represent a monophyletic entity including 15 species, which is restricted in distribution to southeastern Africa (Malawi, Mozambique, South Africa, Swaziland, Zimbabwe), Madagascar, the Mascarenes (La Reunion, Mauritius), and the Seychelles (Mahe). Molecular phylogenetic data based on two nuclear markers (ETS, ITS) and a chloroplast marker (trnL-F) resolve the studied taxa as monophyletic where multiple accessions could be included (except for Costularia laxa and Costularia purpurea, which are now considered conspecific), and indicate that the genus dispersed once to Africa, twice to the Mascarenes, and once to the Seychelles. Two endemic species from Madagascar are here described and illustrated as new to science, as is one additional species endemic to La Reunion. Two taxa previously accepted as varieties of Costularia pantopoda are here recognised at species level (Costularia baronii and Costularia robusta). We provide a taxonomic revision including an identification key, species descriptions and illustrations, distribution maps and assessments of conservation status for all species

Biogeographical patterns of legume-nodulating <i>Burkholderia </i>spp.:from African Fynbos to continental scales

UNLABELLED: Rhizobia of the genus Burkholderia have large-scale distribution ranges and are usually associated with South African papilionoid and South American mimosoid legumes, yet little is known about their genetic structuring at either local or global geographic scales. To understand variation at different spatial scales, from individual legumes in the fynbos (South Africa) to a global context, we analyzed chromosomal (16S rRNA, recA) and symbiosis (nifH, nodA, nodC) gene sequences. We showed that the global diversity of nodulation genes is generally grouped according to the South African papilionoid or South American mimosoid subfamilies, whereas chromosomal sequence data were unrelated to biogeography. While nodulation genes are structured on a continental scale, a geographic or host-specific distribution pattern was not detected in the fynbos region. In host range experiments, symbiotic promiscuity of Burkholderia tuberum STM678(T) and B phymatum STM815(T) was discovered in selected fynbos species. Finally, a greenhouse experiment was undertaken to assess the ability of mimosoid (Mimosa pudica) and papilionoid (Dipogon lignosus, Indigofera filifolia, Macroptilium atropurpureum, and Podalyria calyptrata) species to nodulate in South African (fynbos) and Malawian (savanna) soils. While the Burkholderia-philous fynbos legumes (D lignosus, I filifolia, and P calyptrata) nodulated only in their native soils, the invasive neotropical species M pudica did not develop nodules in the African soils. The fynbos soil, notably rich in Burkholderia, seems to retain nodulation genes compatible with the local papilionoid legume flora but is incapable of nodulating mimosoid legumes that have their center of diversity in South America. IMPORTANCE: This study is the most comprehensive phylogenetic assessment of root-nodulating Burkholderia and investigated biogeographic and host-related patterns of the legume-rhizobial symbiosis in the South African fynbos biome, as well as at global scales, including native species from the South American Caatinga and Cerrado biomes. While a global investigation of the rhizobial diversity revealed distinct nodulation and nitrogen fixation genes among South African and South American legumes, regionally distributed species in the Cape region were unrelated to geographic and host factors.status: publishe

First molecular phylogenetic insights into the evolution of Eriocaulon (Eriocaulaceae, Poales)

Eriocaulon is a genus of c. 470 aquatic and wetland species of the monocot plant family Eriocaulaceae. It is widely distributed in Africa, Asia and America, with centres of species richness in the tropics. Most species of Eriocaulon grow in wetlands although some inhabit shallow rivers and streams with an apparent adaptive morphology of elongated submerged stems. In a previous molecular phylogenetic hypothesis, Eriocaulon was recovered as sister of the African endemic genus Mesanthemum. Several regional infrageneric classifications have been proposed for Eriocaulon. This study aims to critically assess the existing infrageneric classifications through phylogenetic reconstruction of infrageneric relationships, based on DNA sequence data of four chloroplast markers and one nuclear marker. There is little congruence between our molecular results and previous morphology-based infrageneric classifications. However, some similarities can be found, including Fyson’s sect. Leucantherae and Zhang’s sect. Apoda. Further phylogenetic studies, particularly focusing on less well sampled regions such as the Neotropics, will help provide a more global overview of the relationships in Eriocaulon and may enable suggesting the first global infrageneric classification

Threatened medicinal and economic plants of the Sudan Savanna in Katsina State, northwestern Nigeria

Background: The loss of biodiversity in Nigeria is escalating alarmingly. However, there is generally a paucity of information as to what taxa are endangered because of a dearth of functioning conservation agencies in Nigeria. Objectives: The aim of this research is to record the endangered medicinal and other economic plant species in the Sudan Savanna vegetation in Katsina and to provide an assessment of the various threats faced by these plants. Method: Medicinal plants were identified through oral interviews with traditional medical practitioners within the study area. Conservation statuses were assessed using a bespoke data collection and assessment form; the data were then evaluated using the International Union for the Conservation of Nature Red List categories and criteria. Results: A total of 169 species belonging to 62 families were recorded. Of these, 43 taxa were reported to be used for ethnomedicinal practices. It was found that more than half (108) of the 169 species were threatened with extinction and one taxon (Xeroderris stuhlmannii [Taub.] Mendonca Sousa) qualifies as being Extinct locally. Threats recorded include overexploitation (24%), agriculture (15%), deforestation and desertification (12% each), invasive plants (11%), urban residential development (7%) and erosion (6%). Conclusion: Most of the plants are already under threat and require urgent conservation measures. The data point to the critical need for further research into conservation strategies and a more sustainable use of threatened plants. We recommend that the Nigerian government should establish a national Red List agency and ensure effective protected area management and community-based natural resources management