Abstract: Method for assay of the viable cells of Ralstonia solanacearum was established by using methylthiazolyldiphenyl-tetrazolium bromide(MTT) and the parameters like the detection wavelength, bacterial concentration, MTT dosage and incubation time, triplex solution dosage and dissolution time were optimized. Results showed that the best detection wavelength for the reaction of MTT was 512 nm, Ralstonia solanacearum concentration was 0.3 in A600, the dosage of MTT was 30 μL, the reduction reaction of MTT was within 20 min, the dosage of triplex solution for dissolving formazan crystal was 3 mL, dissolved 8 h, and the A512 value was linear with formazan solutions between 10 μL and 120 μL. The study would provide the MTT method for rapid detection of plant pathogenic viable bacteria such as Ralstonia solanacearum, and have potential application value in agricultural products import and export detections.

Key words: Ralstonia solanacearum, MTT, formazan, triplex solution, detection of viable bacteria