CMEG congratulates Marc and Casper on the successful completion of their Ph.D. degrees

Posted on February 12, 2018

The Centre for Microbial Ecology and Genomics (CMEG) recently had two of its Ph.D. candidates successfully complete their degrees. Both Casper Kamutando and Marc W. Van Goethem presented the results of their Ph.D. research projects on Monday 5th February 2018 during their Prestige Seminars, and subsequently defended their theses during oral exams with their examiners. 

CMEG is proud that both candidates completed their degrees within the minimum of three years which were highly productive and led to the publication of 8 manuscripts between the two candidates.
The core research theme at CMEG is understanding soil microbial ecology. Here researchers address how microbial communities differ across spatial and temporal scales, the degree to which soil microbial communities are sensitive to external perturbations and exploring how community members interact to drive important biogeochemical processes in soil.
Dr Kamutando’s research focussed primarily on exploring the roles played by soil microorganisms (particularly, symbionts) residing in the rhizosphere of a highly invasive and damaging tree, Acacia dealbata (Silver wattle) across the grassland biome of South Africa. Using amplicon sequencing data (i.e., 16S rRNA and the Inter-transcriped spacer (ITS) fragments, for bacterial and fungal diversity analysis, respectively), Casper showed that despite a high degree of geographic variability in the diversity and composition of microbial communities, Silver wattle populations shared a core of bacterial and fungal taxa, some of which are known to be involved in nitrogen (e.g., Bradyrhizobium sp.) and phosphorus cycling (e.g., Inocybe sp.), while others are regarded as plant pathogens. This research was published in Scientific Reports [Impact factor (IF): 4.259]. He also studied the plant-growth promoting (PGP) roles of major microbial taxa residing in the rhizosphere of A. dealbata, using shotgun sequencing data. Results suggested that, although these trees associate with several microbial symbionts, Bradyrhizobium strains drive the majority of the PGP functions. This aspect of the thesis is currently under review for publication. The work was also presented at various national platforms. Dr Kamutando’s research findings suggest that A. dealbata populates its rhizosphere soil environment with beneficial microbial taxa, and that, members of the genus Bradyrhizobium play an integral role in the invasive success of this invader in colonizing novel environments. The findings provides a link between A. dealbata root-associated microorganisms and the functions they perform, thereby providing an opportunity to better understand the role of rhizospheric microorganisms in invasive success. This information can be useful in crafting cost-effective management strategies for these damaging and aggressive invasive plants. 
Dr Van Goethem’s research spanned both hot and cold deserts and his thesis titled “Metagenomic analysis of microbial communities in desert soil environments” included research regarding soil and lithic microbial communities from the hyperarid Namib and Antarctic deserts. Marc applied shotgun metagenomic sequencing to understand the taxonomic and functional attributes of microbial communities within the pristine Mackay Glacier ecotone. He showed that Bacteroidetes and Acidobacteria were dominant microorganisms in ecotone soils and revealed their importance to local Carbon and Nitrogen cycling processes. He also sought to test the prevalence and mobility of antibiotic resistance gene elements within the ecotone and presents novel insights into the diversity of antibiotic resistance genes in one of the world’s most pristine environments. This aspect of his thesis was recently accepted for publication in Microbiome [Impact Factor (IF): 8.496]. He also studied the spectrum of microbial interactions among active members of Namib desert hypoliths and found low abundance members of the Cyanobacteria and Alphaproteobacteria to be keystone organisms within this desert environment. This research was published in Frontiers in Microbiology in 2017 [IF: 4.165]. Dr Van Goethem has also published research in journals such as BMC Genomics [IF: 3.729], Current Opinion in Biotechnology [IF: 8.035] and FEMS Microbiology Ecology [IF: 3.875] during his Ph.D.

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