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.