Detection of Ralstonia solanacearum in Potato Tubers by Polymerase Chain Reaction

A new polymerase chain reaction (PCR) assay was developed for the detection of Ralstonia solanacearum in potato tubers. The designed primers PS-1/PS-2 based on the sequence data of the 16S rRNA gene. Using the optimized PCR protocol, it was possible to detect R. solanacearum cells arti®cially added to con- centrated potato extracts in the range of 1±10 colony- forming units (CFU) per PCR reaction mixture (10± 100 CFU/ml potato homogenate). No ampli®cation products were obtained, when bacteria belonging to other species or genera were submitted to PCR under the same conditions. A total of 10 di€erent DNA extraction methods were adapted for the isolation of R. solanacearum DNA from potato homogenates and were compared for their suitability as pre-PCR proce- dures.