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Biological and Conservation

Science Building, Westville Campus

Tel: +27 31 2608657

Fax: +27 31 2601195

Email: 209540511@stu.ukzn.ac.za

MSc Research: Studies on the biological control of micro-organisms by trichoderma hasrzianum and possibly other agents in various explants of recalcitrant-seeded species

Recalcitrant seeds generally harbour a range of fungi and bacteria, which will affect long term storage. Biological control, the use of specific against plant pathogens, is a nature friendly, ecological approach to overcome the problems caused by standard chemical methods of plant protection. Trichoderma spp. as remarkable opportunistic fungal plant symbionts are avirulent and, when located in the sub-epidermal cell layers of roots, produce or release a variety of compounds that induce localized or systemic resistance responses; this explains their lack of pathogenicity to plants.

The research currently proposed will be focused on co-culturing Eco-T and Eco-77 preparations of spores of soil and aerial strains of T. harzianum, resp., with various explants from recalcitrant seeds under in vitro conditions. This may induce antimicrobial molecules such as enzymes, which could adversely affect the fungal pathogens that proliferate from inoculum in these explants. If T. harzianum works effectively as a biocontrol agent in the tissue culture medium, the explants must germinate effectively. In parallel, an alternate approach will utilize liquid culture as well as solid culture medium in which Trichoderma spp. have been grown. This is aimed at testing for the possible presence of compounds released by T. harzianum (without the presence of a host plant) in medium and will examine the effects on selected explants in terms of defence mechanisms that might be potentiated. A biochemical approach for the analysis of the enzymes such as chitinase and beta 1,3 glucanase in filtrate from liquid cultures as well as solid cultures will be done. The efficacy of these procedures will be assessed in terms of successful seedling or plantlet formation, and whether or not there is any survival of the inherent mycoflora.