A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>

[1] _Potato spindle tuber viroid_ - Italy: 1st report, new host
[2] _Potato spindle tuber viroid_ - Austria ex Italy: 1st report
[3] _Citrus exocortis viroid_, _Potato spindle tuber viroid_, _Tomato apical stunt viroid_ - Netherlands: 1st reports, new hosts

******
[1] _Potato spindle tuber viroid_ - Italy: 1st report, new host
Date: January 2008
Source: European Plant Protection Organisation (EPPO) Reporting Service 1/2008/008 [edited] <http://archives.eppo.org/EPPOReporting/2008/Rse-0801.pdf>

_Potato spindle tuber viroid_ detected on ornamental _Solanaceae_ in Italy

In Italy, a limited survey on the occurrence of _Potato spindle tuber viroid_ (_Pospiviroid_, PSTVd -- EPPO A2 List) in ornamental _Solanaceae_ was conducted at the beginning of 2007. A total of 23 symptomless _Solanum jasminoides_ plants were collected at random from 4 nurseries in Central and Southern Italy. Molecular tests were
performed (RT-PCR [reverse transcription-polymerase chain reaction], dot-blot [molecular] hybridization, [nucleotide] sequencing) and revealed the presence of PSTVd in 17 samples of _S. jasminoides_. The study was extended to 2 plants of _S. rantonnetii_ growing in one of the nurseries surveyed and one plant tested positive. This was the 1st record of a natural infection of PSTVd in _S. rantonnetii_.

As these preliminary studies stressed the need for simple, fast, and economic diagnostic methods, a tissue-printing hybridization method was developed. To validate it, 94 samples of _S. jasminoides_ and 106 samples of _S. rantonnetii_ were collected from 3 glasshouses in Apulia. The incidence of PSTVd was 100 percent in _S. jasminoides_ and 26.4 percent in _S. rantonnetii_ (all plants were symptomless). Identical results were obtained when the same samples were tested by dot-blot hybridization and RT-PCR. The identity of the pathogen was also confirmed by sequencing PCR-products obtained from 5 samples. Although, further studies have to be done, in particular on the specificity of the method, tissue-printing hybridization could be a useful tool for the routine detection of PSTVd in ornamental _Solanaceae_.

Although limited to a small number of plants and localities, these preliminary studies have revealed a very high percentage of infected plants, which underlines the need for large-scale surveys in Italy and other European countries on the occurrence of PSTVd in ornamental plants, and the need to produce propagation material free of PSTVd.

--
Communicated by:
ProMED-mail
<promed@promedmail.org>

******
[2] _Potato spindle tuber viroid_ - Austria ex Italy: 1st report
Date: January 2008
Source: European Plant Protection Organisation (EPPO) Reporting Service 1/2008/009 [edited]
<http://archives.eppo.org/EPPOReporting/2008/Rse-0801.pdf>

Incursion of _Potato spindle tuber viroid_ on ornamental _Solanaceae_  in Austria

The Austrian Plant Protection Service recently informed the EPPO Secretariat of the 1st detection of _Potato spindle tuber viroid_ (_Pospiviroid_, PSTVd -- EPPO A2 List) in Austria. During an official monitoring survey, PSTVd was detected in Tyrol on _Solanum jasminoides_ and _Brugmansia_ spp. (_Solanaceae_), at 2 companies producing plants for final consumers. Eradication measures were imposed (all plants of these species were destroyed and the premises disinfected). Sales of _Brugmansia_ spp., _Solanum jasminoides_ and _Solanum rantonnetii_ by the 2 enterprises concerned were suspended. No other occurrence of PSTVd was found. Investigations showed that the infested plants originated from Italy. The Italian Plant Protection Service was informed.

--
Communicated by:
ProMED-mail
<promed@promedmail.org>

******
[3] _Citrus exocortis viroid_, _Potato spindle tuber viroid_, _Tomato apical stunt viroid_ - Netherlands: 1st reports, new hosts
Date: January 2008
Source: European Plant Protection Organisation (EPPO) Reporting Service 1/2008/010 [edited]
<http://archives.eppo.org/EPPOReporting/2008/Rse-0801.pdf>

New host plant records for pospiviroids

Following the recent findings of _Potato spindle tuber viroid_ (_Pospiviroid_, PSTVd -- EPPO A2 List) in ornamental _Solanaceae_ in Europe (such as, _Solanum jasminoides_ and _Brugmansia_), surveys have been initiated in the Netherlands in 2006 to better understand the host status of ornamental plants. Many plant samples have been
collected and tested (RT-PCR, sequencing). Although none of the ornamental host plants showed any symptoms, several samples tested positive for the presence of pospiviroids. In all cases, eradication measures have been applied (destruction of infested lots). The following viroids were identified:
- _Citrus exocortis viroid_ (CEVd) in _Verbena_ sp. (_Verbenaceae_).
It is noted that CEVd had also been recently reported on _Verbena_ in India and the USA.
- _Potato spindle tuber viroid_ (PSTVd -- EPPO A2 List) in _Brugmansia suaveolens_, _Streptosolen jamesonii_, and _Solanum jasminoides_ (all _Solanaceae_).
- _Tomato apical stunt viroid_ (TASVd -- EPPO Alert List) in _Cestrum_ sp. (_Solanaceae_).

--
Communicated by:
ProMED-mail
<promed@promedmail.org>

[_Potato spindle tuber viroid_ (PSTVd; type member of genus _Pospiviroid_) is an important pathogen affecting a number of solanaceous plants including several crop species. It causes the diseases 'spindle tuber' in potato and 'bunchy top' in tomato. Yiel losses can be up to 65 percent in potato and up to 50 percent in tomato. In potato, shoots are spindly and may show distortions and proliferations, plants are stunted, and tubers are small, elongated, cylindrical, spindle or dumb-bell-shaped, with prominent eyes evenly distributed over the tuber. Sprouting is slower than in healthy tubers. Symptoms in tomatoes include stunting, leaf chlorosis and distortion, and shortening of internodes. All varieties of tomato and potato appear to be susceptible, with no natural resistance to PSTVd available in either host. However, mild pathogen strains may cause latent infections in some host cultivars.

PSTVd is seed transmitted in potato at a rate of up to 100 percent, depending on the cultivar, and in tomato at a rate of around 10 percent. Spread occurs also via infected plants or plant parts (including seed tubers or propagative cuttings), pollen, mechanical means, or plant-to-plant contact. Only in the presence of _Potato leafroll virus_ PSTVd can also be transmitted by an aphid vector (_Myzus persicae_). PSTVd (like viroids in general) is exceptionally stable due to its molecular structure and can survive in sap or leaf litter for considerable times.

PSTVd has been found in many countries around the world, including parts of North and South America, Asia, and Oceania. The pathogen is not endemic to Western Europe, but in recent years outbreaks have been reported in France, UK, Germany, and the Netherlands. In addition, the disease is established in Eastern Europe, including for
example Poland and Russia. EPPO has therefore listed PSTVd as a quarantine pathogen.

_Citrus exocortis viroid_ (CEVd; genus _Pospiviroid_) causes bark-shelling, stunting, tree decline, and reduced yields in citrus hosts. Different strains can affect other crops including grapevine, tomato, and some vegetable species. The viroids are transmitted by grafting and mechanical means and, at least in citrus, may show synergistic effects in co-infections with other viroids. Disease management relies mainly on using viroid-free rootstock and grafting material in citrus and grapevine cultivation.

_Tomato apical stunt viroid_ (TASVd; genus _Pospiviroid_) has been included on the EPPO alert list. Until now, very few data were available on its host range other than tomato. Symptoms in tomato are stunting, leaf distortion, reduced fruit size, and discolouration. Up to 100 percent incidence with heavy yield losses has been reported. The viroid is transmitted by plant material, mechanical means, seed, and bumblebees.

The presence of these viroids in a number of symptomless reservoir hosts reported above may pose a threat to crops in the region. It highlights the importance of systematic surveys and quarantine measures for these pathogens, even if there are no obvious problems with crops in the respective areas.

Maps
Italy:
<http://www.aboutromania.com/ItalyMap.gif>  and
<http://healthmap.org/promed?v=42.8,12.1,5>
Austria:
<http://www.mygeo.info/karten/austria.gif>  and
<http://healthmap.org/promed?v=47.6,14.1,5>
Netherlands:
<http://worldatlas.com/webimage/countrys/europe/lgcolor/nlcolor.htm>  and
<http://healthmap.org/promed?v=52.2,5.6,6>
Europe:
<http://www.greece-map.net/europe/europe-map.gif>
Worldwide distribution of PSTVd (September 2006):
<http://www.eppo.org/QUARANTINE/virus/PSTVd/PSTVD0_map.htm>
Worldwide distribution of TASVd (December 2005):
<http://www.eppo.org/QUARANTINE/Alert_List/viruses/maps/TASVD0_map.htm>

Pictures
PSTVd symptoms on tomato:
<http://www.bspp.org.uk/ndr/jan2004/2003-68-2.jpg>
PSTVd affected potato tubers:
<http://vegetablemdonline.ppath.cornell.edu/Images/Potatoes/PotatoViruses/PotatoVirusfs7.jpg>
Photo gallery of PSTVd symptoms on potato and tomato:
<http://www.eppo.org/QUARANTINE/virus/PSTVd/PSTVD0_images.htm>
Citrus exocortis disease:
<http://ccpp.ucr.edu/images/exocortis2.jpg>  and
<http://www.fao.org/docrep/U5000E/U5000E2F.JPG>
TASVd symptoms:
<http://vegetablemdonline.ppath.cornell.edu/Images/Tomato/Tom_ApicalStnt/Viroid_02B.jpg>

Links
Information on PSTVd:
<http://www.defra.gov.uk/planth/pestnote/pstv.htm> and
<http://www.eppo.org/QUARANTINE/virus/PSTVd/PSTVD0_ds.pdf>
Diagnosis of PSTVd:
<http://www.eppo.org/QUARANTINE/virus/PSTVd/pm7-33(1)%20PSTVD0%20web.pdf>
PSTVd taxonomy:
<http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/80.001.0.01.001.htm>
Information on citrus exocortis disease:
<http://plantpathology.tamu.edu/Texlab/Fruit/citrus/cexo.htm>  and
<http://plantpathology.tamu.edu/texlabn/fruits/Citrus/citrus.html#virus>
Tomato apical stunt disease:
<http://www.eppo.org/QUARANTINE/Alert_List/viruses/TASVD0.htm>  and
<http://www.phytoparasitica.org/phyto/pdfs/2002/issue5.pub/ANTI.pdf>
Genus _Pospiviroid_ taxonomy and species list:
<http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/80.001.0.01.htm>
EPPO quarantine and alert lists via:
<http://www.eppo.org/QUARANTINE/quarantine.htm>.  - Mod.DHA]