Antagonistic Properties of some Bacterial Strains Isolated from Sources of Drinking Water against Fungal Pathogen Rhizoctonia solani

Control of phytopathogens by microorganisms means biological control. In this study, three bacterial strains Pantoea agglomerans B1, Serratia plymuthica B2 and Proteus mirabilis B3 are the strains of bacteria originally isolated from source of drinking water a temperate site at El-Gharbia Governorate, Egypt. The origin of isolated bacterial strains contains three sources of drinking water: Nile, tap and ground. The commercialization of this aquaculture has of bacteria generated economic profits while the water contain bacteria produced the antagonistic materials have an adverse effect on the soil-borne fungi. These sources of water are very important in agriculture especially when using for irrigation of crops. In vitro, Pantoea agglomerans B1, Serratia plymuthica B2 and Proteus mirabilis B3 are examined for its antagonistic activities against soil-borne fungi Rhizoctonia solani, the seedlings damping-off fungus for several plants. Serratia plymuthica B2 showed high level of antagonism against fungal growth. Also, production of lytic enzymes (chitinase, ß-1,3 – glucanase), siderophores, salicylic acid (SA) and hydrogen cyanide (HCN) by the three strains of bacteria were evaluated. All antagonistic materials production recorded high-level values with strains B2 and B1 respectively. A most high relationship between the antagonistic potential of three bacterial strains against R. solani and its level of ß-1,3 – glucanase, SA and HCN were observed. The antifungal metabolites by the bacterial strains mentioned were considered contributing to the antagonistic activities of these bacteria.