Incidence and genetic diversity of raspberry bushy dwarf virus and raspberry leaf blotch virus isolates in red raspberry in Ukraine

Abstract

The objective of this study was to assess the prevalence and genetic diversity of raspberry bushy dwarf virus (RBDV) and raspberry leaf blotch virus (RLBV) in Ukrainian raspberry plantations. A survey of viral symptoms, including yellow leaf blotch, leaf distortion, mottling, and crumbly fruits, was conducted across several regions. Crumbly fruits were linked to RBDV infection, while yellow leaf blotch and leaf distortion were associated with RLBV and the presence of eriophyid mites, which serve as RLBV vectors. To detect the presence of these viruses, 195 symptomatic and asymptomatic leaf samples were collected from cultivated raspberry fields and tested using RT-PCR. The overall infection rate was 33.3%, with RBDV detected in 29.2% of the samples and RLBV in 4%. Comparison of sequences of the Ukrainian RBDV isolates showed high nucleotide and amino acid identity and grouped them with isolates from Belarus, Sweden, and Kazakhstan. RLBV isolates from Ukraine displayed notable genetic variability, clustering with isolates from Finland, Serbia, and Slovakia. These findings highlight a high level of virus infections in raspberry plantations in Ukraine. Despite the obligatory certification of planting material, RBDV remains a significant threat to raspberry farming. Furthermore, the emergence and spread of RLBV in Ukraine could further worsen the situation.