|Lee, Ing Ming|
Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 2/25/2002
Publication Date: N/A
Technical Abstract: R. solanacearum has a broad host range and can be subdivided into 4 races and 5 biovars according to the plant host and biochemical properties. R. solanacearum race 3/biovar 2 primarily infects potato and is the phenotype responsible for recent outbreaks of potato brown rot disease in several countries of western Europe. This biovar has never been reported to be present in the US and is under strict quarantine. Brown rot disease is spread primarily by latently infected seed potatoes, in which concentration of the pathogen is generally low. A highly sensitive and rapid method for detection and identification of this pathogen is needed for use in routine screening. In the present study PCR/RFLP based method was developed and used for the detection of R. solanacearum race 3/biovar 2. PCR using one of the two primer sets RSIS F2/R1 (yielded a 1250bp fragment) and RSIS F1/R1 (yielded a 850bp fragment), which were designed based on a highly repetitive novel insertion sequence present in biovar 2, provided a reliable tool for sensitive and specific detection of all the R. solanacearum biovar 2 strains tested. The identity of the pathogen detected was verified by collective RFLP profiles obtained by analyses of PCR products with several restriction enzymes. This approach has been applied recently for identification of R. solanacearum strains isolated from geranium in the US. All twenty-three strains from geranium were identified to be race 3/biovar 2. Moreover, Southern hybridization analysis indicated that the R. solanancearum geranium strains in the US are very closely related to the R. solanacearum potato biovar 2 strains responsible for the recent outbreaks of potato brown rot in Europe.