Phylotype and sequevar of Ralstonia solanacearum which causes bacterial wilt in Curcuma alismatifolia Gagnep.
Bacterial wilt of Curcuma alismatifolia (Patumma) caused by Ralstonia solanacearum is a major disease affecting the quality of rhizome exports. Traditionally, R. solanacearum is classified into five races based on differences in host range and six biovars based on biochemical properties. Recently a classification scheme based on phylotypes and sequevars was presented by the scientific community as a tool for determining phylogenetic relationships within R. solanacearum. This study used traditional and molecular methods to identify R. solanacearum strains from Patumma. All the strains were identified as biovar 4. A phylotype-specific multiplex PCR-based phylotyping of all the isolates detected the phylotype I-specific amplicon of 144 bp and the R. solanacearum-specific 281 bp amplicon. Phylogenetic analyses of endoglucanase (egl) sequences clustered all three strains of Patumma into phylotype I, sequevar 48 with reference strains M2 and M6. The study determined that the R. solanacearum strains from Patumma belong to biovar 4, phylotype I that originated from Asia, and sequevar 48.