The analysis of the virome associated with Freesia refracta plants with necrotic disorder sheds new light on the phylogenetic relationships in the Konkoviridae and Yueviridae families

Authors: MARRA, MONICA - Council For Research And Experimentation In Agriculture – Research Centre For Industrial Crops; ROTUNNO, SILVIA - Council For Research And Experimentation In Agriculture – Research Centre For Industrial Crops; FRASCATI, FULCO - Council For Research And Experimentation In Agriculture – Research Centre For Industrial Crops; PIERRO, ROBERTO - Council For Research And Experimentation In Agriculture – Research Centre For Industrial Crops; Hammond, John; VAIRA, ANNA MARIA - Council For Research And Experimentation In Agriculture – Research Centre For Industrial Crops; MIOZZI, LAURA - Council For Research And Experimentation In Agriculture – Research Centre For Industrial Crops

Submitted to: Virology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2026
Publication Date: 3/12/2026
Citation: Marra, M., Rotunno, S., Frascati, F., Pierro, R., Hammond, J., Vaira, A., Miozzi, L. 2026. The analysis of the virome associated with Freesia refracta plants with necrotic disorder sheds new light on the phylogenetic relationships in the Konkoviridae and Yueviridae families. Virology Journal. 23. Article 73. https://doi.org/10.1186/s12985-026-03075-8.
DOI: https://doi.org/10.1186/s12985-026-03075-8

Interpretive Summary: Virus infection of ornamental plants often reduces the visual appeal of the plants, affecting quality in addition to losses of productivity. A necrotic streaking disease of freesia foliage causing considerable economic losses has been recognized for more than 50 years in Europe, and has since been reported in other regions of the world where freesia are grown for cut flowers or as garden plants. While freesia sneak virus was associated with the necrosis in 2006, this virus could not be detected in all plants with necrotic streak symptoms; therefore a high-throughput sequencing study of freesia samples collected in 2011, 2014, and 2022 was carried out to detect other possible viruses contributing to the necrotic streaking disease. Two new viruses were detected, belonging to different virus families, the Konkoviridae and the Yueviridae, in addition to freesia sneak virus; while two other viruses having no known association with necrotic symptoms were detected in most tested plants, including three plants with mild or no obvious symptoms. Each of the new viruses and freesia sneak virus were individually detected in multiple plants, in various combinations. Freesia sneak virus and the newly-discovered konkovirus each showed high but not absolute correlation with the observed necrosis, and both were detected together in several symptomatic plants. These results will be valuable to freesia breeders and producers working to improve the health and productivity of the crop, and to virologists studying the group of viruses to which these viruses belong.

Technical Abstract: The necrosis syndrome of freesia, first described in 1970 in Northern Europe, is still jeopardizing freesia cultivation all over the world. Although several viruses have been listed as possible causal agents, the etiology of the disease is still not clear and is possibly linked to a combination of different factors. In this study, a high-throughput sequencing virome analysis was performed on total RNA extracts derived from symptomatic freesia leaves; a novel virus putatively belonging to the recently ratified Konkoviridae family in the Bunyaviricetes class has been identified and characterized, for which we propose the name of freesia konkovirus 1 (FreKV-1). This family, officially listing only one genus and two species, has been expanded by exploring publicly available metatranscriptomic datasets through the Serratus Project Database and reconstructing new viral entities; the phylogenetic position of the Konkoviridae family has been investigated and new genera belonging to the family have been proposed. Moreover, a further previously unknown virus, putatively belonging to the Yueviridae family was partially characterized and its phylogenetic position was discussed. Overall, the analysis increased our knowledge of the number of viral agents infecting freesia and possibly involved in freesia necrosis syndrome.