Abstract：Ralstonia solanacearum causes a lethal wilting disease on many important crops in tropical, subtropical and warm regions in the world. The research of genetic diversity of R. solanacearum plays an important part in knowing the appearance and prevalence of bacterial wilt diseases. The special primer was used to identify R. solanacearum strains, in which 84 strains of R. solanacearum from different host plants in the Fujian Province were identified with a specific band in the location of 504 bp. Meanwhile, the genetic diversity of these R. solanacearum strains was assessed by Box element polymerase chain reaction (BOX-PCR) and Repetitive extragenic palindromic polymerase chain reaction (REP-PCR) method. Based on their genomic fingerprints, 19 specific bands were amplified in the BOX-PCR and 20 specific bands were amplified in the REP-PCR. The cluster analysis showed that the genetic diversity of R. solanacearum was concerned with geographic origin and host plants, respectively. The different host plants played a leading role in the genetic difference of R. solanacearum, while the difference of regions was mainly provided by the BOX-PCR, and the difference of host plants was mainly provided by REP-PCR. At the same time, there were some special fragments of R. Solanacearum from different regions in BOX-PCR patterns. Moreover, there were also some special fragments of R. Solanacearum from different host in REP-PCR patterns. Therefore, R. Solanacearum from different regions and hosts could be identified by these special fragments. All of results indicate that REP-PCR and BOX-PCR can provide an alternative way for the study of genetic diversity of R. solanacearum.
