Seed and soilborne diseases are a primary barrier to crop production especially in low income countries, where retained seed is cultivated in monocrop systems. Even in the presence of soil disinfestation by fumigation, soilborne pathogens will incite enormous damage during the course of plant growth, since fumigation is short lived and creates biological vacuums, which are rapidly colonised by pathogenic and parasitic species.
Sustainable management of seed and soilborne diseases, can be attained by developing novel biological control products obtainable from plant tissue and rhizosphere microbe communities resident or found in close proximity with plants. Including beneficial fungi, plant growth promoting bacteria and yeasts. These microbes serve different functions as antibiosis, predation, lytic enzymes production, chemical interference, competition, induction of host resistance against pathogenic and parasitic organisms. Furthermore, they provide beneficial functions as phosphate solubilisation, ammonia, indole acetic acid and siderospore production which promote plant growth.
My proposed project will bioprospect for beneficial fungi, bacteria and yeasts in various plants (medicinal, underutilised and other potential plants in undisturbed environments), to develop biological products used in the management of important soil and seed pathogens. These include Fusarium, Phytopythium, Phytophtora, Rhizoctonia, Sclerotia spp. Specific attention will be on disease management of underutilised crops as amaranth, cactus pear, bambara nuts, cowpea, chia, fonio and teff, although the project can expand to other food security crops. These crops have been underutilised in South Africa and other areas in Africa, yet they have a potential to broaden the food base in drought areas.
This project is underway (illustration below), endophytic yeasts and bacteria from seed and root of teff, cactus pear, cowpea, amaranth and chia have already been isolated using selective medium and stored for subsequent use. These groups will be tested for antibiosis to Fusarium, Phytopythium, Phytophtora, Rhizoctonia, Sclerotia spp Invitro and invivo, in the above mentioned crops. As well, they will be tested for growth promotion activity as phosphate solubilisation, ammonia, indole acetic acid and siderospore production. Successful candidates will be identified using molecular techniques, and subsequently developed into different formulations of biocontrol products.
To develop an effective biocontrol product, the proposed product will be a mixture formulation that provides a range of plant beneficial effects, since these microbes might provide single or few beneficial effects to plants. Other activities as field testing, formulation determination will be conducted until the biological control product is registered.
Considering, the proposed product might manage other plant pathogens such as nematodes, above ground diseases and postharvest diseases, I plan to seek collaboration for a broad-spectrum activity test. Since the product under development is targeting under-utilised crops, positive success stories will be reported mostly from resource-poor farmers in the communal areas. Principally, the environmentally safe product will be cost effective and might be applied in low quantities hence saving production costs and promote sustainable usage. The product also will concurrently act as a biocontrol and organic fertiliser, allowing compatibility with other good agricultural practices such as crop rotation, mulching and use of composts.
Makomborero Nyoni, South Africa