Rep-PCR Analyses Reveal Genetic Variation of Ralstonia solanacearum Causing Wilt of Solanaceaous Vegetables in Bangladesh.

Ralstonia solanacearum, a soil-borne and seed-borne plant pathogenic bacterium, causes bacterial wilt to several important crop plants causing substantial economic losses. To provide population information on this pathogen for developing effective control strategies, Rep-PCR was used to analyze the genetic variation of 18 representative isolates of R. solanacearum collected in Bangladesh. Phenotypic analyses revealed that all eighteen isolates belong to biotype 3 with wide diversity in aggressiveness on eggplant, tomato, and chili. Rep-PCR studies utilizing the REP, ERIC, and BOXIR primers showed a wide variation at the genetic level among the R. solanacearum isolates used in this study. Dendrogram constructed using REP, ERIC, and BOXIR primers based on banding patterns implied that R. solanacearum isolates were genetically diversified and distributed in four clusters at 83%, 80%, and 63% similarity index, respectively. The genetic relationship assayed by rep-PCR highlighted a wide range of genetic variation but no relation among geographical origin, aggressiveness, and phylogenetic groups of R. solanacearum isolates. These results conceded that other molecular markers related to virulence gene(s) might reveal the complex relationship among geographical origin, aggressiveness, and phylogenetic groups.