Responses of a sterile red fungus to soil types,wheat varieties and the presence of certain isolates ofStreptomyces

The biological activities of a sterile red fungus (SRF) capable of plant growth promotion and suppression of take-all disease were investigated in soils collected from Lancelin, Newdegate and Mt. Barker regions of Western Australia. Further, the effects of three wheat cultivars and the presence of two isolates ofStreptomyces on the biological activities of the SRF were tested using the Lancelin soil. The biological activities of the SRF were greatest in the Lancelin and Newdegate (wheat field) soils and with the wheat cultivar Gutha. In in vitro studies the soil streptomycetes tested showed either a significant increase in the exudate production by the SRF, which had antifungal and growth promoting properties, or an inhibition of growth of the fungus. Streptomycete A63 which stimulated the exudate production by the SRF in vitro, however, did not enhance disease protection in vivo. On the other hand, protection from root rot by the SRF in vivo was reduced in the presence of the streptomycete isolate Ax which is capable of inhibiting the growth of the SRF in vitro.