BIOCONTROL OF FUSARIUM SPECIES BY SOIL BACTERIA

It is estimated that about 17-55% of the yield from all agricultural crops is lost due to plant diseases. These are caused by various pathogens, including bacteria, viruses, nematodes and fungi. Fusarium, a common soil borne fungal pathogen, invades the plant through the roots and interferes with the water conducting vessels of the plant. As the infection spreads up into the stems and leaves it restricts water flow, causing the foliage to wilt.

In agriculture, chemical pesticides are used against Fusarium. However, due to development of resistance the relevance of chemical pesticides decreases and there is an increasing demand for healthy food products without toxic residues. These have lead the quest for new and environmental friendly measures of protecting the crops such as biocontrol.

The objective of this study is to identify a biological solution for the control of diseases caused by soil borne Fusarium. We are looking for solution such as inhibitory bacteria themselves, or their secondary metabolite with an inhibitory effect upon the fungus mycelium and/or spores germination ("green" chemical solution). Bacteria were isolated from different soils collected throughout Israel and screened for their antifungal activity in vitro against Fusarium, seven of them were selected for in planta experiments. Till now two were already tested, one of which showed an inhibitory effect on the disease in plants. High diversity of spore forming Bacillus was found to have features of such activities. These isolates and their metabolites (211 fractions were tested including crude, C18 and LH20 fractions, and 87 of them showed inhibition effect) were tested for their antagonistic activity in vitro and in planta.