Grouping of Ralstonia solanacearum strains in Tochigi Prefecture based on pathogenicity to Solanum plants and discriminating pathogenicity groups by PCR.

Abstract

Strains of Ralstonia solanacearum from eggplant and tomato fields in Tochigi Prefecture separated into four distinct groups (I, II, IV and one unknown) based on differences in pathogenicity to four species of Solanum plants. In repetitive sequence-based polymerase chain reaction (rep-PCR) DNA fingerprinting to discriminate the strains belonging to each pathogenicity group, two characteristic bands were identified. One was universally amplified from all tested strains, and the other was amplified only from strains in groups I, II and V. Based on the DNA sequences of the bands, we designed two more PCR primer sets (RsUp-F and RsUp-R, and RsDwn-F and RsDwn-R) that discriminated the strains in group I, II and V from those in III and IV.