Sambucus nigra, S. kamtschatica and S. racemosa plants growing in natural habitats or commercial nurseries in Poland, showing symptoms of vein clearing or chlorotic patterns were found to be naturally infected with Cherry leaf roll virus (CLRV). Nine virus isolates were characterized by enzyme-linked immunosorbent assay (ELISA) and sequence analysis of RNA2 fragments. Serological test using ELISA kits raised against elderberry, birch, cherry and ash isolates of CLRV showed that tested virus isolates reacted with all polyclonal antibodies used in the experiment. Genetic analysis of 3’ non-coding region fragments (3’NCR) of isolates originating from elderberries revealed high level of their sequence identity (more than 95%). All tested isolates clustered exclusively within phylogenetic group E of CLRV. Analysis of polyprotein open reading frame (P2 ORF) fragments showed higher sequence variability, with nucleotide identity ranging from 88 to 93%. This indicates that analysis of P2 ORF fragments may be more suitable for studying CLRV population diversity than analysis of 3’NCR region. Phylogenetic analysis of CP gene sequences confirmed clustering of tested isolates in monotypic group. Overall, the serological and phylogenetic data suggest a host-specific nature of CLRV variants infecting Sambucus spp. plants in Poland.

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