HOST RANGE VARIATION AND GENETIC DIVERSITY OF IRANIAN ISOLATES OF RALSTONIA SOLANACEARUM FROM POTATO AND TOMATO WITH RAPD AND (GTG)5-PCR

Of 170 Iranian isolates of Ralstonia solanacearum from wilting potato and tomato plants, 130 were analyzed for genetic and pathogenicity diversity. Specific PCR assays identified all the isolates as R. solanacearum biovar N2 (2T) and 2A. Based on pathogenicity and PCR tests, the isolates were divided into two pathogenic groups. Group I, corresponding to race 3, was pathogenic to potato and tomato, whereas group II, corresponding to race 1, was pathogenic to tomato, potato, eggplant and tobacco. Molecular analysis was done with random amplified polymorphic DNA (RAPD) and rep-PCR using (GTG)(5) primer. RAPD and (GTG)(5)-PCR analysis divided the 130 Iranian isolates of R. solanacearum into eight haplotypes that were grouped in three clusters. Cluster I comprised all biovar 2A isolates with four haplotypes, cluster II and III contained biovar N2 isolates with four haplotypes. Both RAPD and (GTG)(5)-PCR enabled discrimination of R. solanacearum strains according to biovar and the host of origin.