Physiological and biochemical characterization of Ralstonia solanacearum inciting bacterial wilt of brinjal

Abstract

Ralstonia solanacearum causes bacterial wilt of solanaceous crop plants including brinjal, a most devastating in humid tropic. Ten different isolates of the causal bacterium R. solanacearum were isolated from naturally wilted brinjal plants collected from different locations of Dapoli tahsil and were characterized. Gram’s staining and Potassium hydroxide solubility test revealed that all isolates of R. solanacearum were Gram negative in reaction and positive reaction for motility test. The all isolates of R. solanacearum were positive in acid production, gas production, starch hydrolysis, hydrogen sulphide production, cellulose decomposition and catalase activity. In case of methyl red test appearance of red colour indicates strong acid forming ability of the bacterium, while retaining of normal colour of the medium indicates alkalinity and negative reaction.