Comparison of Bacillus subtilis isolates, the fengycin antibiotic producer and non- ‎producer isolates in Rhizoctonia solani AG2-2 control, causing crown and root rot of ‎sugar beet

Bacillus subtilis has a good potential for plant pathogens control due to the formation of endospores, tolerance to variable pH conditions, wide thermal range and because of antibiotics production. In this study, the biocontrol potential of native Bacillus against Rhizoctonia solani AG2-2 was evaluated.Fengycin many antibiotic extracted and the relationship between antibiotic-producing isolates with sugar beet root and crown rot control, investigated in the greenhouse.In laboratory and greenhouse tests, 82 selected Bacillus subtilis isolates with 2 standard antagonist isolates were used.Of the 84 isolates, in double culture test in petri dish, isolate UTB1with 55.3% had the most inhibitory effect. In greenhouse tests, bacterial isolates UTB27, UTB65 and UTB71, reduced disease by 60.09% (the most inhibitory on disease). Of the 84 bacterial isolates, 52 isolates had a significant effect on wet and dry weight of plant.Of the 84 bacterial isolates in the HPTLC assay, for antibiotic extraction, 19 isolates produced fengycin and 65 isolates were unable to produce. In the greenhouse test, 75 bacterial isolates reduced disease, which was significant at 5% level, and 19 isolates of them were producing fengycin. The native bacterial isolate UTB1 is a good candidate for a successful biocontrol agent.