Fungal Diseases Occurring on Trees of Namibia

During the past few years, disease symptoms in many Acacia trees in the Windhoek Municipality area and the rest of Namibia have been observed. This observation triggered the investigation of phytopathological aspects that are reported in this chapter. The importance of indigenous trees of the Namibia flora is apparent considering that Namibia has two old deserts within its borders: the Namib Desert and the Kalahari Desert. Nambia’s tourism and meat industry are dependent on the indigenous trees of Nambia flora. The trees are the primary source of vegetation land cover (attracting tourists), and they provide browsing food matter to domestic livestock and wild animals (sources of meat). Hence, it is important to ensure that a healthy vegetation is maintained in this area.. This survey is the first dedicated step to find ways of protecting them from disease-causing agents. The aim of this survey is to investigate the possible causes of disease symptoms in trees. It is important to understand the biology of the pathogenic agents to propose a possible method to control the diseases. The survey involved sampling leaves, stems and roots from dying trees that show symptoms such as branch girdling, gum oozing and defoliation, suspicious general twig wilting and die-back. The survey was carried out in places where symptoms were observed. The tree surveys were done on Aloe zebrina, Tylosema esculentum, Syzygium and Acacia species. Primary isolations from plant material and then single-spore pure cultures were made for identification. In this chapter, we report isolation and identification of Microsphearopsis sp., Dreschelra sp., Botryosphearia spp., Acremonium spp., Coniothyrium sp., Phellinus spp., Cytospora sp., Fusarium sp., Scytalidium sp., Phoma spp., Gliomastix sp., Trichoderma koningii, Peacilomyces variotii, Alternaria citri and Curvularia palescens from the diseased trees. This work is still ongoing. This study paves way for proper designing of control methods to protect crops, trees and their biodiversity. The protection of plant biodiversity ensures better reaping of food products and other ecosystem services and products. Without knowledge of the identity of these disease-causing agents, it is not possible to accurately identify and manage threats to food production and threats to the native botanical biodiversity of Namibia

Molecular plant-pathogen interactions with special reference to Eucalyptus Grandis polygalacturonase-inhibiting proteins and fungal polygalacturonases

Phytopathogenic fungi parasitise plants for survival. Knowledge of the interactions between plants and these fungi is of importance in designing control strategies. In this thesis the interactions of Eucalyptus polygalacturonase-inhibiting proteins (PGIPs) and fungal polygalacturonases (PGs) were characterised. About thirty years of research on the interaction between PGIPs and PGs was reviewed in Chapter 1. The gene sequences of the mature PGIP peptides from selected Eucalyptus species were determined in Chapter 2. The PGIP genes have very high similarities among themselves, signifying conservation of the function of PGIPs in this genus. Molecular characterisation of the endoPG gene of C. cubensis was presented in Chapter 3. This endoPG gene occurs more than two times in the genome of C. cubensis. The gene sequences of the other endoPGs remain to be determined. EndoPG production by C. cubensis, a Eucalyptus canker pathogen, was presented in Chapter 4. It was found that polygalactw:onases probably have a minor role in determining the levels of pathogenicity in different C. cubensis isolates. However, the hypovirus CHVl-173 has a role in reducing polygalacturonase production in infected hypovirulent C. cubensis isolates. Chapter 5 dealt with the interaction between Eucalyptus PGIPs and endoPGs from different fungal pathogens. Coniothyrium zuluense and Botryosphaeria dothidea produced more PGs than C. cubensis and Phytophthora cinnamomi in liquid culture. Disease tolerant Eucalyptus TAG5 clones produced PGIPs that are more effective in inhibiting endoPGs from C. zuluense than the susceptible Eucalyptus ZG14 clones. In Chapter 6 the gene sequence of the endoPG of Fusarium circinatum was detennined. This :fungus causes the . pitch canker disease in pine trees. This endoPG gene occurs as a single copy and is related to those of other Fusarium spp. The results presented in this thesis add to the current scientific knowledge pertaining to the role of PGIPs and PGs in pathogenic interactions, especially, between Eucalyptus PGIPs and fungal endoPGs. Interaction of Eucalyptus PGIPs and fungal endoPGs was demonstrated; therefore it is possible to genetically engineer Eucalyptus for more disease tolerant Eucalyptus plants using PGIP genes, especially, against Coniothyrium zuluense. This means that more research is needed to identity genes that will give a more global protection against many fungal pathogens.Thesis (PhD (Plant Biotechnology))--University of Pretoria, 2006.Geneticsunrestricte

The Namibian bioeconomy: transformation to a sustainable society?

Worldwide, bioeconomy is promoted as an ‘engine for sustainable development’. However, increasingly, the notion that ‘the bioeconomy’ will facilitate sustainable development per se is challenged. Based on the assumption that when leaving the relations between ‘nature’ and ‘society’ unquestioned, inherent inequalities are rather reproduced than overcome, we draw upon a social-ecological framework to analyse the societal relations to nature in the Namibian bioeconomy. In Namibia, with independence, an array of different benefit-sharing mechanisms have been developed to implement local participatory governance structure, which will be further streamlined under the newly introduced access and benefit-sharing law. Results show that despite efforts to facilitate a diversity-based bioeconomy, separating structures and trade-offs are persistent. Images of ‘nature’, like the ‘eternal Namibian landscape’, that draw upon colonial notions are frequently used to market indigenous natural products. Institutions to ‘nature’ that guarantee fair and equitable terms of trade are often only short-term and/or small-scale, e.g. as shown at the case of Devil’s claw, Hoodia and Namibian Myrrh. Even when perspectives cannot be assigned in a stereotypical way between user and provider, and instead, all actors refer to biodiversity and traditional knowledge as ‘welfare of the people’, ‘cultural heritage’, ‘input for R&D’, ‘community benefit’, and ‘marketing tool’, a rational-instrumental reasoning tends to be favoured of a normative-ethical one. A more diversified awareness towards the dialectics entailed in the conception, making, and management of ‘nature’ potentially inhibiting an inclusive sustainable development is relevant at any theory–practice interface, including development project-management and environmental policy-making

Metagenomics reveals seasonality of human pathogenic bacteria from hand-dug well water in the Cuvelai Etosha Basin of Namibia

Namibia is a large country with a population slightly above 2 million of which 73% live in rural areas. It is the driest country in sub-Saharan Africa with unpredictable rainfall patterns which occur between October and May. The Cuvelai Etosha Basin is a rural setting in which most people depend on groundwater to circumvent water scarcity by the construction of hand-dug wells. Communities consume hand-dug well water throughout the year without; knowledge of its safety, and treatment prior to use. Hence, this study aimed at evaluating the seasonal safety and quality of hand-dug well water for human consumption. A 16S rRNA metagenomics study was conducted to explore the influence of season on the human pathogenic bacterial species richness, diversity, evenness and abundance in the hand-dug wells. Bacterial pathogens were identified and analysis revealed no significant difference in species richness and diversity, and a significant difference in species evenness and abundance between the wet and dry seasons. Hence, seasonality had an influence on human bacterial pathogens evenness and abundance but had no influence on species richness and diversity. In addition, the water in hand-dug wells of the Cuvelai Etosha Basin is not safe for consumption and domestic use unless sanitized. It is recommended that efforts should be made to treat the water prior to use, and hand-dug wells should be properly constructed to reduce contamination

Redefining Global Food Security: Do we really have a Global Food Crisis?

With the Climate change effects becoming more and more undoubted in the world populations, the reality of food production trends taking a negative curve is clear. This bring up the questions of whether the farmers will be able to produce food for the sustenance of the world population or not? The rate of developing food shortage coping mechanisms in this regard is slower that the ravaging negative climate change effects of drought and floods on farm performance. This commentary has the aim of requesting a fresh discussion around the fundamentals of what is food, what is a food security and what is nutritional security? It is possible that the humanity has a perception that needs refocusing. This is a perception that some people may choose out of non-food safety issues not to eat certain foods while other however healthily eat such food. It therefore becomes hard to technically accept that food is in short supply for those the opt not to eat that which is edible

Factors facilitating sustainable scientific partnerships between developed and developing countries

International scientific partnerships are key to the success of strategic investments in plant science research and the farm-level adoption of new varieties and technologies, as well as the coherence of agricultural policies across borders to address global challenges. Such partnerships result not only in a greater impact of published research enhancing the career development of early and later stage researchers, but they also ensure that advances in plant science and crop breeding technologies make a meaningful contribution to society by brokering acceptance of emerging solutions to the world problems. We discuss the evidence showing that despite a lack of funding, scientists in some African countries make a significant contribution to global science output. We consider the criteria for success in establishing long-term scientific partnerships between scientists in developing countries in Southern Africa (“the South”) and developed countries such as the UK (“the North”). We provide our own personal perspectives on the key attributes that lead to successful institutional collaborations and the establishment of sustainable networks of successful “North-South” scientific partnerships. In addition, we highlight some of the stumbling blocks which tend to hinder the sustainability of long-term “North-South” scientific networks. We use this personal knowledge and experiences to provide guidelines on how to establish and maintain successful long-term “North-South” scientific partnerships.National Research Foundation of South Africa, Winter Cereal Trust and African Union Research Grant Programme funded by the European Union.http://journals.sagepub.com/home/oaghj2021Forestry and Agricultural Biotechnology Institute (FABI)Plant Production and Soil Scienc

Development and use of microsatellites markers for genetic variantion analysis, in the Namibian germplasm, both within and between populations of marama bean (Tylosema esculentum)

Tylosema esculentum (marama) has long been identified as a candidate crop for arid and semi-arid environments due to its success in these environments and the high nutritional value of the seed. Molecular markers are essential for the assessment of the levels of genetic variation present within and between populations of marama as well for future marker-assisted breeding efforts. Microsatellites were isolated using a modified FIASCO enrichment technique. Eighty pairs of primers were designed to amplify across a selected set of perfect microsatellite repeats with greater than 5 repeat units. Of the 80 primer pairs screened, 76% were able to detect polymorphism and 21% gave monomorphic bands while the other 3% gave inconsistent results. Four of the polymorphic SSR’s were used for genetic variation analysis and have proved to be useful and informative markers for assessing intra-specific and interspecific variability of marama bean. Heterozygosity (H) within and between populations of marama bean in the Namibian germplasm ranged from 0.30 to 0.74. Some of the populations had low genetic variation while others had high genetic variation

Biocontrol Potential of Forest Tree Endophytes

Peer reviewe

Identification of Fungi Associated with Processed-Food Contamination at Open Markets of Windhoek, Namibia

With the ever-increasing pace of urban life, many people now rely a lot on processed foods. Some of these processed foods are prepared hygienically and yet some are prepared in homestead and brought to the open market, without having gone through any microbial quality checks. This has in the recent past led to outbreaks of food -borne diseases such as Cholera and Salmonellosis to mention a few. In this study, processed food samples were collected from three open markets in Windhoek namely Single quarters, Soweto market and the Okuryangava Bus stop. The samples included maize (flour), dried Cleome gynandra leaves, mopane worms, roasted groundnuts, minnos, and cooked beef steaks. Morphological identification was done based on the macroscopic characters based on the colour, shape, and texture and microscopic characterization using lactophenol cotton blue wet mount. DNA was extracted from the fungal isolates and PCR was performed using ITS1 and ITS4 primers. The PCR products were sequenced, and the results were used for identification using the BLAST search program in NCBI. Dried Cleome gynandra contained most of the isolated fungal species which were identified Pichia burtonii, P. macrostoma, Dothidealus, and A. parasiticus. However, Aspergillus species were present in all the food samples and A. parasiticus was found in all food samples except the ground nuts. These could be an indication of that the fungus prefers low water activity and possibly high salt concentrations to survive