The nodule bacteria of South African encroaching legumes

Abstract

South Africa has an astounding plant species endemism, with a plethora of fynbos adorning Table Mountain and thorn trees lining the African skyline. However, the bacterial diversity associated with these plants remains largely unexplored. The primary goal of this dissertation was to investigate the diversity of bacteria residing within the root nodules of South African woody legumes, with the ability to fix atmospheric nitrogen – a defining characteristic of rhizobia. The significance of this investigation is underscored by the intersection of scientific curiosity and environmental stewardship. South African legume-nodule systems have often been overshadowed by research on crop legumes in the global scientific community. This research sought to rectify this situation by focusing on the diversity of South African nodule bacteria and the associations they form with woody legume hosts. In Chapter 1, an extensive literature review sheds light on the history of rhizobial systematics and the prospects of this dynamic field. In the first research chapter (Chapter 2), soil samples were collected from various geographic locations across South Africa while focusing on the same legume host. Conversely, in Chapter 3, identical soil was used for rhizobial trapping experiments, but with different host plants