Genetic Diversity of Potyviruses Associated with Tulip Breaking Syndrome

Tulip breaking is economically the most important viral disease of modern-day tulip growing. It is characterized by irregular flame and feather-like patterns in the flowers and mosaic on the foliage. Thirty-two leaf samples were collected from cultivated tulip plants showing tulip breaking syndrome from Hungary in 2017 and 2018. Virus identification was performed by serological (ELISA) and molecular (RT-PCR) methods. All samples proved to be infected with a potyvirus and evidence was provided that three potyvirus species could be identified in the samples: Lily mottle virus (LMoV), Tulip breaking virus (TBV) and Rembrandt tulip-breaking virus (ReTBV). Recombination prediction accomplished with Recombination Detection Program (RDP) v4.98 revealed potential intraspecies recombination in the case of TBV and LMoV. Phylogenetic analyses of the coat protein (CP) regions proved the monophyletic origin of these viruses and verified them as three different species according to current International Committee on Taxonomy of Viruses (ICTV) species demarcation criteria. Based on these results, we analyzed taxonomic relations concerning potyviruses associated with tulip breaking syndrome. We propose the elevation of ReTBV to species level, and emergence of two new subgroups in ReTBV.

The occurrence of the Tulip breaking virus in tulips in the northern part of Turkey

The tulip (Tulipa sp.) is one of the most important ornamental bulbous plants, which has been cultivated as a cut-flower, potted, and garden plant, and used for landscaping in Turkey. This study investigated the occurrence of a viral disease in the tulip cultivars Strong Gold, Pretty Woman and Purple Prince that causes striping of the leaves, flames of different colours on the petals and mosaic patterns on the leaves, in Samsun province of Turkey. Surveys of virus-infected tulip plants were carried out in the Middle Black Sea Region of Turkey in 2015-2016. A total of 212 samples were collected from four locations and checked by biological, serological and molecular methods for the presence of the Tulip breaking virus (TBV). TBV was detected in the leaves and flowers by double-antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISA) in the tulip cultivars (15.5%) tested from Samsun province. TBV infection was found at the highest rate in the cultivar Strong Gold (19.7%), followed by Pretty Woman (14.1%) and Purple Prince (12.8%). The presence of TBV in samples was further confirmed by reverse transcription polymerase chain reaction (RT-PCR) assays. This is the first report on TBV naturally infecting tulips in Samsun province, Turkey.

Occurrence and molecular analysis of quarantine virus in lily cultivation areas in Brazil

The objective of this work was to describe the occurrence of quarantine Tulip breaking virus (TBV, synonym Lily mottle virus - LMoV) and Lily symptomless virus (LSV), and their respective molecular analyses, to provide data for supporting TBV removal from the Brazilian A1 quarantine pest list, since this virus has spread among the main commercial lily crops in Brazil. The occurrence of these viruses was detected in 12 cultivation areas through multiplex reverse transcription (RT-PCR), using specific primers to genes encoding the respective coat proteins (CP). Eight fragments of 800 nucleotides (nt) obtained from the LMoV-infected lilies and nine fragments of 600 nt from LSV-infected lilies were sequenced. Phylogenetic tree reconstruction showed a robust branch containing the LMoV Brazilian sequences, other LMoV isolates, TBV, and Tulip band breaking virus, suggesting that all are LMoV isolates, although they are clustered into two subgroups. Phylogenetic analysis also showed a robust branch supporting all Brazilian and other LSV sequences, except for an LSV Japanese isolate. Recombination analyses also showed an LMoV recombinant isolate, whereas no recombination events were found among LSV isolates. Lily mottle virus is the prevalent virus in lily crops in Brazil, in single and mixed infections with LSV or Cucumber mosaic virus (CMV).