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Description of Bradyrhizobium species associated with southern African legumes
Dissertation (MSc (Microbiology))--University of Pretoria, 2016.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613574613958656 |
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| access_status_str | Open Access |
| author2 | Venter, S.N. (Stephanus Nicolaas) |
| author_browse | Venter, S.N. (Stephanus Nicolaas) |
| author_facet | Venter, S.N. (Stephanus Nicolaas) |
| collection | Thesis |
| description | Dissertation (MSc (Microbiology))--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110109 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:18.923Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110109 Description of Bradyrhizobium species associated with southern African legumes Venter, S.N. (Stephanus Nicolaas) juanita0790@gmail.com Steenkamp, Emma Theodora Van Zyl, E. Avontuur, Juanita Rayleen Legumes Non-native Southern Africa Brodyrhizobium Dissertation (MSc (Microbiology))--University of Pretoria, 2016. Bacterial systematics and taxonomy provides a framework for all microbiological research, ranging from ecology to cell biology. The overarching goal of these related fields are to generate a classification system that is predictive, stable and one that ideally should reflect the natural relationship between organisms. Over the years, bacterial taxonomy has been continuously influenced by methodological developments resulting in new approaches to bacterial species classifications and leading to different opinions in the requirements for describing novel species. Criteria used for the descriptions of Bradyrhizobium species has changed over the years. Like other bacteria, Bradyrhizobium species are classified based on a number of techniques. The use of Multi-Locus Sequencing Analysis (MLSA), is one of the techniques that has allowed for significant advances in Bradyrhizobium taxonomy and has resulted in a robust way for the delineation of new species. New methodological developments (especially in terms of whole genome sequencebased approaches) have also been gradually incorporated in the description of Bradyrhizobium species and have contributed to the increased number of Bradyrhizobium species. Compared to the other rhizobial genera, the genus Bradyrhizobium for a long time contained fewer validated species. Due to the lag of the description of new species, members of this genus are referred to as being related to either B. japonicum and B. elkanii. In previous studies, Bradyrhizobium isolates associated with southern Afican legumes have been reported to be either B. japonicum or B. elkanii-like species. Therefore, the overall aim of this study was to delineate and formally describe new Bradyrhizobium isolates, specifically those reported from various cultivated and native southern African environments. A review of literature pertaining to bacterial systematics and taxonomy is presented in Chapter 1. The main focus of this chapter is to review the current status of and future prospects for rhizobial taxonomy, using the genus Bradyrhizobium as an example. An overview of the genus is provided, followed by a discussion of the current techniques used for the identification and classification of rhizobia, particularly Bradyrhizobium species. The shift towards a genome-based bacterial vi classification system from a system based upon diagnosable characters is also considered. Chapter 2 aims to describe new Bradyrhizobium species belonging to the Bradyrhizobium elkanii supergroup by making use of a polyphasic approach. The isolates were first delineated using MLSA, followed by genome-based techniques [i.e. DNA-DNA hybridization and Average Nucleotide Identity (ANI)]. Relevant descriptions containing phenotypic properties, host range, geographical origin and nodulation capabilities of the new Bradyrhizobium species conclude this chapter. Chapter 3 focuses on the Bradyrhizobium isolates associated with promiscuous legume hosts (Vigna unguiculata, Arachis hypogaea and Acacia species), sampled in southern Africa. These isolates were subjected to MLSA to determine their taxonomic positions, where after phenotypic characterisation incorporating growth abilities, fatty acid and metabolic activities is evaluated. In addition, the genomebased approach is also used to distinguish between isolates, using ANI values. Microbiology and Plant Pathology MSc (Microbiology) 2026-05-15T17:26:19Z 2026-05-15T17:26:19Z 16/08/01 2016 Dissertation http://hdl.handle.net/2263/110109 en application/pdf |
| spellingShingle | Legumes Non-native Southern Africa Brodyrhizobium Description of Bradyrhizobium species associated with southern African legumes |
| title | Description of Bradyrhizobium species associated with southern African legumes |
| title_full | Description of Bradyrhizobium species associated with southern African legumes |
| title_fullStr | Description of Bradyrhizobium species associated with southern African legumes |
| title_full_unstemmed | Description of Bradyrhizobium species associated with southern African legumes |
| title_short | Description of Bradyrhizobium species associated with southern African legumes |
| title_sort | description of bradyrhizobium species associated with southern african legumes |
| topic | Legumes Non-native Southern Africa Brodyrhizobium |
| url | http://hdl.handle.net/2263/110109 |