Survey of viruses affecting Solanum species in UK gardens

RHS project team

Anna Platoni and Gerard Clover

Partners

University of Cambridge (John Carr, Beverley Glover)

Start date

07/07/2015 14:43:55

End date

30/09/2016 15:00:00

Keywords

virus, Solanum, ornamental, survey

The problem

Plants in the genus Solanum are affected by a wide range of virus and virus- like diseases. Some of these are established in the UK, such as Cucumber mosaic virus, Potato leafroll virus and Tomato spotted wilt virus. However, Defra’s risk register lists 30 viruses and 4 viroids affecting Solanum that are of plant health concern to the UK.

Little is known about the virus status of solanaceous plants grown in UK gardens. The viruses affecting the crop plants (aubergine, potato, tomato) have been well characterised but no surveys have been undertaken in gardens and RHS Gardening Advice receives few physical samples of such species.

The viruses affecting ornamental Solanum are not well characterised although there are a few documented observations. For example, Davino et al. (2008) reported that Cucumber mosaic virus infected Solanum jasminoides causing leaf mosaics and malformation. S. jasminoides, and S. rantonnetii have been reported to be infected with Potato spindle tuber viroid, and S. jasminoides with Chrysanthemum stunt viroid and Potato virus M (Verhoeven et al. 2006; Di Serio, 2007).

These last three pathogens are all regulated in the UK and the infections were symptomless, demonstrating the potential importance of these hosts in international movement of plant diseases.

Request for samples

Gardeners are requested to help in this research by sending in samples of leaf material from:

1. Ornamental species of Solanum, for example S. crispum and S. laxum (previously known as S. jasminoides), whether or not they look like they are virus-infected. This is because some viruses that affect these plants can be symptomless in ornamentals.

2. Tomato, potato and aubergine, if they have virus symptoms (see picture below).
 

Please include the name of the plant the sample was taken from (Latin name, common name and / or cultivar), the postcode of where the plant is growing as well as date of planting and place of purchase if known. Please also provide your name and email or postal address.

Several whole leaves should be taken from your chosen plant. Put the fresh leaves in a slightly inflated sealed bag and post this to:

Anna Platoni,
Plant Health - Science,
RHS Garden Wisley,
Nr Woking
GU23 6QB

Please include the postcode of where the plant is growing as well as date of planting and place of purchase if known. If you would like to receive results from the experiment please provide your name and email or postal address.

We will let you know if your plant tests positive for viruses and will post a report online so gardeners can see the overall results.
 

[From top] Symptoms of Cucumber mosaic virus on tomato (Edward Sikora, Auburn University, Bugwood.org) / Symptoms of Potato leafroll virus on potato (Eugene E. Nelson, Bugwood.org) / Symptoms of Tomato spotted wilt virus on potato (Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org) / Symptoms of Tomato spotted wilt virus on tomato

Approach

Leaf material will be collected from Solanum species, including symptomatic and asymptomatic ornamental species (eg. S. crispum and S. laxum); and symptomatic crop species (S. lycopersicum, S. melongena and S. tuberosum).
Samples will be collected from RHS members via the advisory service and from RHS Gardens. A direct request for samples will be made using print and social media.

RNA will be extracted and tested by RT-PCR using primers for Cucumber mosaic virus (genus Cucumovirus; family Bromoviridae) As resources allow, subsequent tests may be done for:

a) Other pollen and seed-transmitted viruses in the family Bromoviridae, such as Tomato aspermy virus (genus Cucumovirus) and Tobacco streak virus (genus Ilarvirus) (Untiveros et al., 2010) and

b) Viruses on the Defra risk register such as Pepino mosaic virus and Potato spindle tuber viroid.

The sequence of representative virus isolates will be determined and phylogenetic analysis undertaken to determine the relationship between isolates from garden hosts and those from crop hosts.

Benefits to gardeners

The RHS will be able to improve the advice that we give to gardeners about plant viruses including improving the capability of our diagnostic service. We will be able to gauge the potential for diseases to move between crop and ornamental plants, and contribute to protecting plants from viruses that are not established in the UK. The RHS will be able to improve the advice that we give to gardeners about plant viruses including improving the capability of our diagnostic service. We will be able to gauge the potential for diseases to move between crop and ornamental plants and contribute to protecting plants from viruses that are not established in the UK.

Further information

Viruses of Solanum survey leaflet
Plant viruses
Tomato viruses
See Anna Platoni's blog profile for updates on her work
 

References

Davino, S., Di Serio, F., Polizzi, G. and Tessitori, M. (2008) First report of Cucumber mosaic virus infecting Solanum jasminoides in Italy. Plant Disease 92, 1585.

Di Serio, F. (2007). Identification and characterization of Potato spindle tuber viroid infecting Solanum jasminoides and S. rantonnetii in Italy Journal of Plant Pathology 89, 297-300.

Untiveros, M., Perez-Egusquiza, Z. and Clover, G.R.G. (2010). PCR assays for the detection of members of the genus Ilarvirus and family Bromoviridae. Journal of Virological Methods 165, 97-104.

Verhoeven, J.Th.J., Jansen, C.C.C. and Roenhorst, J.W. (2006). First report of Potato virus M and Chrysanthemum stunt viroid in Solanum jasminoides. Plant Disease 90, 1359.