Identification and fermentation of antagonistic bacterium against Ralstonia solanacearum

Abstract:

The objective of this study was to screen and identify antagonistic bacteria against Ralstonia solanacearum from tomato rhizosphere soil. Four strains (YB1, YB6, YB22, YB70) showed strong antagonistic activity, with diameters of inhibition zone above 9 mm. The strain YB6, identified as Arthrobacter sp. according to its morphological, physiological and biochemical characteristics, presented the best and most stable effect against R. solanacearum. The fermentation conditions of the strain YB6 were 30 °C, pH 9.0, inoculum 3%, shaking at 100 r/min, sucrose as carbon source, and yeast condensate as nitrogen source. Under the optimized fermentation conditions, diameters of inhibition zone produced by the strain YB6 against R. solanacearum strains SST-Y and G2M1.70 increased by 76.72% and 81.14%, respectively.

Key words:Ralstonia solanacearum, Antagonistic bacteria, Physiological and biochemical characteristics, Fermentation condition, Antibacterial activity