|VAIRA, ANNA MARIA - National Research Council - Italy|
|MIOZZI, LAURA - National Research Council - Italy|
|VALLINO, MARTA - National Research Council - Italy|
|CARRA, ANDREA - National Research Council - Italy|
|LENZI, RICARDO - National Research Council - Italy|
|SALVI, DAVIDE - Studio Ferrari Salvi|
|PAPPU, HANU - Washington State University|
Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 5/11/2017
Publication Date: 2/2/2018
Citation: Vaira, A., Miozzi, L., Vallino, M., Carra, A., Lenzi, R., Salvi, D., Hammond, J., Pappu, H. 2018. Evidence of new viruses infecting freesia hybrids showing necrotic disease. Acta Horticulturae. 1193:21-27. 10.17660/ActaHortic.2018.1193.4.
Interpretive Summary: A disease causing moderate to severe necrosis in leaves of the important floral crop freesia has been recognized in Europe since about 1970. Although several viruses have been associated with the disease, the causal agent was not definitively identified, hindering efforts to eliminate the disease from this vegetatively propagated crop. A team of scientists identified at least one newly-detected virus in symptomatic freesia plants from Italy and Bulgaria, possibly representing a new taxonomic grouping. We plan to develop methods for specific detection of this newly-discovered virus to screen for the presence of the new virus in freesia stocks from other locations, and to select plants free of the virus for production of healthier plants, benefitting bulb producers and flower growers.
Technical Abstract: Different cultivars of Freesia plants with necrotic symptoms were collected in the Sanremo area of Northern Italy. Symptomatic foliar tissue was used both for mechanical inoculation of Nicotiana benthamiana and for virus purification. Total virus-enriched RNA extract was tested by Sequence-Independent Amplification (SIA) to get preliminary information about the presence of both known and previously undescribed viruses. In parallel, Next Generation Sequencing (NGS) of total RNA extracted from mechanically inoculated N. benthamiana plants was performed in order to identify the transmissible unknown virus(es). Using this information, we identified a previously undescribed mechanically transmissible RNA virus, presumably belonging to the Phlebovirus or Tenuivirus genus, here provisionally named Freesia leaf necrosis associated virus (FreLNaV), likely involved in the necrotic disease. Moreover, novel virus sequences ascribable to DNA viruses belonging to Caulimoviridae family were also identified.