Genomic polymorphism of isolates of Phytophthora ramorum from Polish ornamental nurseries compared with other European and North American isolates

We undertook an analysis of the genomic relationships between 15 isolates of Phytophthora ramorum Werres, de Cock et Man in't Veld, obtained from symptomatic plants growing in Polish ornamental nurseries, and 2 representatives of the European population and 3 of the North American population. Dendrograms were generated by UPGMA based on 786 amplification products obtained in ISSR-PCR reactions. The representatives of the European population and 13 of the "Polish" isolates formed a common cluster. The other 2 "Polish" isolates, which were found in 1998, and the 3 American representatives formed 2 separate clusters. There was no observed link between genomic distance on the basis of polymorphism and the origin of the isolates from plant species.