New Disease Reports
New Disease Reports (2017) 36, 16. [http://dx.doi.org/10.5197/j.2044-0588.2017.036.016]
Get pdf (810 KB)
Next > < Prev

First report of Broad bean wilt virus 2 in Veronica gentianoides in the UK

A. Fowkes 1*, A. Skelton 1, V. Harju 1, I. Adams 1, R. Ward 1, A. Buxton-Kirk 1, S. Forde 1, R. Witham 2 and A. Fox 1

*aimee.fowkes@fera.co.uk

Show affiliations

Received: 28 Jul 2017; Published: 27 Oct 2017

In August 2016 a sample of Veronica gentianoides cv. Tissington White was submitted to Fera Science Ltd. from a nursery in West Sussex. The sample was submitted with symptoms of severe distortion and mottling and these symptoms were widespread throughout the nursery which could affect their marketability. The sample was tested by ELISA for Cucumber mosaic virus (Agdia, USA), Arabis mosaic virus, potyviruses, Tobacco ringspot virus, Tomato ringspot virus and Tomato spotted wilt virus (DSMZ, Germany), Impatiens necrotic spot virus and Strawberry latent ringspot virus (Bioreba, Switzerland). The sample was negative for all viruses tested. The sample was subsequently tested for Tobacco rattle virus using RT-PCR with specific primers (Mumford et al., 2000) but also tested negative.

To check for the presence of virus the sample was then mechanically inoculated onto Chenopodium quinoa, Nicotiana benthamiana, N. hesperis and N. occidentalis P1. Thirteen days post inoculation all plants showed symptoms such as chlorotic spots, distortion and necrosis (Figs. 1-2). 

RNA was extracted from symptom-bearing leaves of N. benthamiana using an RNeasy Plant Mini Kit (Qiagen, UK), and a sequencing library prepared using the Scriptseq complete plant root kit (Illumina, UK) and sequenced along with other indexed samples on an Illumina MiSeq using a 2x300 bp V3 kit. 61,857 paired reads were produced and analysed as described by Adams et al. (2014). Ten contigs totalling 8,236 bp were identified having between 94-96% identity at the nucleotide level to substantial parts of the bipartite genome of Broad bean wilt virus 2 (BBWV-2). The protein sequence of the combined coat proteins had between 88-98% identity to that of coat proteins of different isolates of BBWV-2 found on GenBank. Figure 3 shows a neighbour joining tree (1000 replicates) produced using MEGA6 (Tamura et al., 2013) of the coat protein genes of this isolate (GenBank Accession No. MF429951) compared to other members of the family Secoviridae. This confirms it as a member of the species BBWV-2.

To confirm the identification, material from N. benthamiana was tested by ELISA (DSMZ, Germany; reference number AS-0862, and LOEWE, Germany; reference number 07017S) using a positive control (PC-0862) and was found to be positive with both antisera.

BBWV has previously been found on V. scutellata in New York (Rist & Lorberr, 1989) though it was not specified whether BBWV-1 or BBWV-2 was present. BBWV-2 has been previously detected in Digitalis and Salvia officinalis in the UK (Mumford et al., 2006). This is thought to be the first confirmed finding of BBWV-2 in Veronica.

Figure1+
Figure 1: Ringspots on Nicotiana benthamiana caused by Broad bean wilt virus 2.
Figure 1: Ringspots on Nicotiana benthamiana caused by Broad bean wilt virus 2.
Figure2+
Figure 2: Systemic necrosis and chlorosis on Nicotiana hesperis caused by Broad bean wilt virus 2.
Figure 2: Systemic necrosis and chlorosis on Nicotiana hesperis caused by Broad bean wilt virus 2.
Figure3+
Figure 3: Neighbour joining tree constructed from coat protein genes of representative members of the family Secoviridae. Bootstrap values greater than 70% (expressed as percentages of 1000 replications) are shown on branches. The bar scale indicates the number of differences.
Figure 3: Neighbour joining tree constructed from coat protein genes of representative members of the family Secoviridae. Bootstrap values greater than 70% (expressed as percentages of 1000 replications) are shown on branches. The bar scale indicates the number of differences.

Acknowledgements

This testing was funded through the Defra-Fera Long Term Service Agreement.

References

  1. Adams IP, Skelton A, Macarthur R, Hodges T, Hinds H, Flint L, Nath PD, Boonham N, Fox A, 2014. Carrot yellow leaf virus is associated with carrot internal necrosis. Plos One 9.   [http://dx.doi.org/10.1371/journal.pone.0109125]
  2. Mumford RA, Jarvis B, Harju V, Boonham N, Skelton A, 2006. First report of Broad bean wilt virus 2 in the UK: findings in foxglove and salvia. Plant Pathology 55, 819.  [http://dx.doi.org/10.1111/j.1365-3059.2006.01478.x]
  3. Mumford RA, Walsh K, Barker I, Boonham N, 2000. Detection of Potato mop top virus and Tobacco rattle virus using a multiplex real-time fluorescent reverse-transcription polymerase chain reaction assay. Phytopathology 90, 448-453.  [http://dx.doi.org/10.1094/PHYTO.2000.90.5.448]
  4. Rist DI, Lorbeer JW, 1989. Occurrence and overwintering of Cucumber mosaic virus and Broad bean wilt virus in weeds growing near commercial lettuce fields in New York. Ecology and Epidemiology 79, 65-69.  [http://dx.doi.org/10.1094/Phyto-79-65]
  5. Tamura K, Stecher G, Peterson D, Filipski A, Kumar S, 2013. MEGA6: Molecular Evolutionary Genetics Analysis version 6.0. Molecular Biology and Evolution 30, 2725-2729.  [http://dx.doi.org/10.1093/molbev/mst197]
To cite this report: Fowkes A, Skelton A, Harju V, Adams I, Ward R, Buxton-Kirk A, Forde S, Witham R, Fox A, 2017. First report of Broad bean wilt virus 2 in Veronica gentianoides in the UK. New Disease Reports 36, 16. [http://dx.doi.org/10.5197/j.2044-0588.2017.036.016]

©2017 The Authors