ARS | Publication request: Carlavirus detection 2008 to 2011 in Germany using electron microscopy

Submitted to: International Society for Horticultural Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: January 15, 2012
Publication Date: N/A

Technical Abstract: Latency of animal and human viruses has been well studied in viruses such as Herpes viruses and Retroviruses. Although the term “latent” has long been used in the naming of numerous plant viruses, a detailed functional analysis of this phenomenon is missing in plants. Carlaviruses belong to the family of Betaflexiviridae with the type member carnation latent virus. Forty-three members were listed by ICTV in 2009. Samples obtained from 2008 to 2011 included the monocot host plants comprising the families Alliaceae and Convallariaceae as well as dicot host plants out of the families of Cactaceae, Ericaceae, Passifloraceae, Ranunculaceae, Scrophulariaceae and Solanaceae. At least 10 different carlaviruses have been identified using immunosorbent electron microscopy (ISEM). In Alliaceae, Cactaceae, Ranunculaceae and Solanaceae mixed infections were frequent. Depending on the host, mixed infections consisted of two different carlaviruses or included a carlavirus and one of the following: poty- allexi-, potex-, tobamo- or cucumovirus. Thus, symptom expression was variable. Special attention has been paid to carlaviruses in Helleborus spp. Whereas Carnation latent virus and Helleborus net necrosis virus were identified in Helleborus in Germany in 2008, 2010 and 2011, Helleborus mosaic virus was found in 2011 and only in Aconitum spp. Currently, ultrathin sections of healthy as well as infected hellebores leaf tissue are analyzed for presence of virions and viral induced-changes in ultra-cellular structures. In Solanum jasminoides and Vaccinium spp., serological identification of carlaviruses was insufficient. Therefore, RT-PCR followed by sequencing has been employed to verify and/or improve ISEM results.