New Disease Reports
New Disease Reports (2004) 9, 41.
Next > < Prev

Isolation and identification of a novel tymovirus from Nemesia in the UK

A.L. Skelton 1*, B. Jarvis 1, R. Koenig 2, D.E. Lesemann 2 and R.A. Mumford 1

*a.skelton@csl.gov.uk

Show affiliations

Accepted: 14 Jul 2004

A sample of Nemesia sp. cv 'Aromatica Light Pink', received from a commercial grower in north west England, showed leaf symptoms including chlorotic flecking and necrosis. Testing by ELISA was negative for several common viruses including Tomato spotted wilt virus, Impatiens necrotic spot virus, Cucumber mosaic virus, Broad bean wilt virus and Alfalfa mosaic virus. Following mechanical inoculation on to a range of indicator plants, leaf symptoms were observed on Nicotiana benthamiana (systemic mosaic and distortion), N. hesperis (systemic yellow spotting and distortion) and N. occidentalis P1 (systemic yellowing, distortion and necrosis). Examination of leaf samples by transmission electron microscopy revealed isometric virus particles, approximately 30 nm in diameter.

A virus serologically related to the tymovirus Scrophularia mottle virus (ScrMV) had been previously reported in Nemesia in Germany (Koenig & Lesemann, 2000). Sap extracted from leaves of indicators showing symptoms and the original Nemesia sample were tested using a polyclonal antiserum obtained from DSMZ (Braunschweig, Germany), that had been raised against ScrMV. All samples tested strongly positive by ELISA. Isolates named as ScrMV, isolated from Nemesia and Diascia species, were obtained from the DSMZ virus collection. A host range comparison between these three isolates was conducted using mechanical inoculation onto indicator plants; all three had an identical host range. Although related serologically, the virus from Nemesia displayed a host range quite different from that reported for the type isolate of ScrMV, isolated from Scrophularia nodosa (Hein, 1959; Bercks et al. 1971; Bercks 1973).

Koenig & Lesemann (2000) reported that a similar virus isolated from Nemesia and Diascia was not ScrMV but a distinct tymovirus, for which the name Nemesia ring necrosis virus (NeRNV) is proposed. NeRNV has been partially sequenced and primers designed to differentiate between ScrMV and NeRNV (Koenig, unpublished). Using these primers the three Nemesia/Diascia isolates were tested by RT-PCR and NeRNV was detected in all three; no ScrMV was detected.

This is the first report of a tymovirus from a member of the Scrophulariaceae in the UK, including Nemesia. The results strongly suggest that the virus is NeRNV and not ScrMV. NeRNV has since been detected in several Nemesia and Diascia samples from the UK and elsewhere in Europe, which suggests that the virus may be widespread in Europe.

Acknowledgements

This work was carried out under the DEFRA Plant Health Division/CSL MoU.

References

  1. Hein A, 1959. Beiträge zur Kenntnis der Viruskrankheiten an Unkräutern. V. Ein Virus von Scrophularia nodosa L. Phytopathologische Zeitschrift. 36, 290-301.
  2. Bercks R, Huth W, Koenig R, Lesemann D, Paul HL, Querfurth G, 1971. Scrophularia Mottle virus: Charakterisierung und Vergleich mit anderen Viren der turnip yellow mosaic virus-Gruppe. Phytopathologische Zeitschrift 71, 341-356.
  3. Bercks R, 1973. Scrophularia mottle virus. CMI/AAB Descriptions of Plant Viruses No. 113. Wellesbourne, UK: Association of applied Biologists.
  4. Koenig R, Lesemann DE, 2000. Ein Tymovirus aus den Zierplanzen Diascia und Nemesia - wie zuverlässig ist die Serologie bei der Identifizierung von Pflanzenviren? Phytomedizin 30, 16-17.
This report was formally published in Plant Pathology

©2004 The Authors