Evaluation of genetic diversity of Ralstonia solanacearum causing bacterial wilt of ginger using REP_PCR and PCR-RFLP

Abstract

Thirty-three strains of Ralstonia solanacearum Yabuuchi (Smith) isolated from ginger, paprika, chilli, tomato, Chromolaena and potato from Kerala, Karnataka, West Bengal and Assam in India, were phenotypically and genotypically characterized. Phenotypic characterization for biovar revealed the predominance of biovar 3 in India. Molecular analysis by REP-PCR, ITS-PCR and RELP-PCR classified the strains into three clustere at 70% similarity, where ginger strains are grouped in clusters I and II. Strains from potato (biovar 2) clustered in the III cluster. Molecular analysis also revealed that ginger strains isolated from different locations during different years had 100% similarity according to Dice’s coefficient. The analysis further revealed that the genetic diversity of Ralstonia is very low within ginger, conforming that the pathogen population is of clonal lineage and is distributed through ‘rhizome transmission’ of the inoculums between locations and also between seasons within the locality.