Genetic characterization of an Indian isolate of Ralstonia solanacearum race 3/ biovar 21 phylotype MB from potato

摘要

The objective of this study was to genotype brown rot pathogen of potato isolated from Pundibari, West Bengal, India. The polyphasic phenotypic and genotypic characterization revealed that the R. solanacearum causing brown rot of potato belongs to race 3/biovar 2/phylotype IIB (R3/B2/PhyllB). The genotypic methods such as BOX-PCR, Phylotyping, 16SrDNA, 16-23S-intergenic spacer, recN gene sequence comparison and Multilocus Sequence Typing (MLST) revealed that the strain was genetically identical to R3/B2 strain of R. solanacearum reported in Bolivia, Brazil, Kenya, Israel, the Netherlands, Belgium, Burundi and Thailand. The strain shared all eleven gene sequences such as 16S rDNA (1420bp), 16-23S rDNA intergenic region (1282bp), recN(1169bp), gdhA (774bp), adk(420bp), gyrB (873bp), ppsA (717bp), gapA (774bp), eg/(693bp), hrpB (810bp), and filC(318bp) with R3/B2/PhyllB strains reported worldwide. In depth genotypic analysis revealed that the strain causing potato brown rot in India traced its originin R3/B2/PhyllB strain reported from South America, Europe, Africa, Middle East and Asia further suggest that the strain is an introduced one.The result also reaffirms worldwide occurrence of this particular race 3 strains. Perusal of records revealed that this is the first report on detailed genetic characterization of Indian R3/B2/PhyllB strain of R. solanacearum.