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[1] Tomato leaf curl Patna virus and satellite - India: new
begomovirus
[2] Tomato necrotic spot virus - USA: new ilarvirus
[1] Tomato leaf curl Patna virus and satellite - India: new
begomovirus
Date: May 2009
Source: The American Phytopathological Society (APS), Plant
Disease [edited] <http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-5-0545B>
[Ref: P Kumari et al: A new begomovirus species causing tomato
leaf curl disease in Patna, India. Plant Dis 2009; 93(5), 545;
DOI: 10.1094/PDIS-93-5-0545B]
During December of 2007, a severe leaf curl disease of tomato
(ToLCD) occurred in tomato-growing areas in the Patna District
of Bihar, India. Viral DNA was isolated from symptomatic tomato
plants and begomovirus association was confirmed by PCR. Cloned
viral genomic and beta satellite DNA could infect _Nicotiana
benthamiana_ and tomato test plants, which exhibited typical
symptoms characteristic of ToLCD.
Full-length viral genome consists of 2752 nucleotides [nt] and
showed the highest identity (85.8 percent) with _Tomato leaf
curl Laos virus_. The satellite DNA-beta component consists of
1349 nt and showed the highest identity (75.8 percent) with
Tomato leaf curl Joydebpur beta satellite. On the basis of the
ICTV [International Committee on Taxonomy of Viruses] species
demarcation criteria of 89 percent of DNA-A sequence identity,
the present isolate was considered as a new begomovirus species
and named Tomato leaf curl Patna virus (ToLCPaV). Since the
isolated DNA-beta satellite shares less than 78 percent
identity, it is considered a new species of beta satellite and
the name, Tomato leaf curl Patna beta satellite
(ToLCPaB) is proposed.
These results show that severe ToLCD in Patna is caused by a
newly identified species of begomovirus and beta satellite.
--
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[2] Tomato necrotic spot virus - USA: new ilarvirus
Date: May 2009
Source: The American Phytopathological Society (APS), Plant
Disease [edited] <http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-5-0546C>
[Ref: O Batuman et al: An outbreak of a necrosis disease of
tomato in California in 2008 was caused by a new ilarvirus
species related to _Parietaria mottle virus_. Plant Dis 2009;
93(5), 546; DOI: 10.1094/PDIS-93-5-0546C]
During the 2008 early-summer growing season, virus-like necrosis
symptoms, most similar to those induced by _Tobacco streak
virus_ (TSV), were observed in leaves, stems, and petioles of
processing tomato plants in the Central Valley of California
[see ProMED-mail post no. 20080820.2593]. Symptoms were observed
in numerous fields in Merced, San Joaquin, and Yolo counties,
though the incidence of the disease in most fields was not high
(not more than 5 percent but over 20 percent in some areas).
Antibody-based tests of representative samples of the disease
for infection with _Tomato spotted wilt virus_, TSV, and _Tomato
apex necrosis virus_, which cause similar symptoms, were
negative. A putative virus-like agent was sap- and
graft-transmitted to tomato plants and induced necrotic spots in
leaves and stem and petiole necrosis symptoms that were similar
to those observed in the field.
Eventually, these plants recovered from these symptoms. In
sap-transmission experiments, the virus-like agent induced
systemic symptoms in _Chenopodium quinoa_ and _C. amaranticolor_
(stunting, leaf curl and necrosis), _Nicotiana benthamiana_
(necrotic leaf and stem lesions), _N. tabacum_ cultivars Havana
and Turkish (stunted growth, necrotic etching, and ringspots
followed by recovery for Havana but not for Turkish), and
_Datura stramonium_ (mild mottle and ringspots in newly emerged
leaves followed by recovery); no symptoms were observed in
inoculated common bean, pumpkin, pepper [capsicum], and _N.
glutinosa_ plants.
Polyacrylamide gel electrophoresis analyses of leaves from
noninfected and infected _D. stramonium_ plants revealed a
protein band of around 29 kDalton in infected but not
noninfected plants.
Four peptides from the protein each had the highest match with
the capsid protein (CP) of _Parietaria mottle virus_ (PMoV), an
ilarvirus that induces leaf and stem necrosis in tomatoes in
Europe.
Reverse transcription-PCR amplified the expected-sized fragments
for ilarvirus from leaves with the unusual necrosis symptoms.
Sequence analyses confirmed these were ilarvirus fragments.
Partial RNA 1, 2, and 3 sequences were 81, 84, and 82 percent
identical, respectively, with those of PMoV and 80, 77, and 69
percent identical, respectively, with those of TSV. The amino
acid sequence of the CP gene was 86 and 61 percent identical to
those of PMoV and TSV, respectively.
Together, these results indicate the necrosis disease of tomato
is caused by a new ilarvirus species, tentatively named Tomato
necrotic spot virus, although further studies are needed to
confirm this. The mode of transmission of this new ilarvirus to
tomatoes in the field is unknown, but it may involve thrips
feeding on infected pollen, a known method of transmission for
TSV.
--
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[Known species in the tomato leaf curl and tomato yellow leaf
curl clades of genus _Begomovirus_ cause similar diseases on
solanaceous crops and can lead to considerable yield losses.
Begomoviruses are transmitted by different whitefly vectors and
many can also be transmitted by mechanical means and grafting,
but they are not seed transmitted. Begomovirus control is
particularly difficult in open field crops due to the widespread
presence and wide host range of whiteflies. Disease management
may include pathogen exclusion, vector control, and elimination
of possible pathogen and/or vector reservoir plants. In some
cases, crop cultivars with increased virus resistance are
available.
A number of new begomoviruses have emerged recently (see
previous ProMED-mail posts below). Some species can have
extra-genomic, virus-dependent satellite DNAs, which may play a
role, for example, in pathogenicity.
_Tobacco streak virus_ (TSV; genus _Ilarvirus_) affects a number
of crops, including bean, sunflower, peanut, maize, soybean, and
a range of vegetable and ornamental species. It is probably
distributed worldwide and has been reported to be spreading in
North America and Oceania. _Parietaria mottle virus_ (PMoV;
genus _Ilarvirus_) has been reported from Italy and Spain, and
its hosts include parietaria weed (wall pellitory;
_Urticaceae_), tomato, bean, English spinach, basil, and
mungbean. Symptoms vary seasonally and include mosaic, mottling,
or necrotic patching on leaves.
TSV, like many ilarviruses, is transmitted by thrips vectors
(_Frankliniella occidentalis_ and _Thrips_ spp.). TSV can also
be transmitted by mechanical inoculation and grafting, and by
pollen to the pollinated plant; it is seed-transmitted in some
species to different extents, but is not transmitted by contact
between plants.
PMoV is transmitted by mechanical means and grafting and no
insect vectors are known so far. The modes of transmission known
for these related ilarviruses will need to be tested for the new
species reported in item 2.
The species of _Chenopodium_, _Nicotiana_ and _Datura_ mentioned
above are widely used in plant virology as diagnostic indicator
hosts.
Maps
India:
<http://www.globalsecurity.org/military/world/india/images/IndiaMap_tourism.gif>
and
<http://healthmap.org/r/00bs>
USA:
<http://www.mapsofworld.com/usa/usa-state-and-capital-map.html>
and <http://healthmap.org/r/00aj>
Pictures
Tomato leaf curl disease:
<http://susveg-asia.nri.org/images/svcorkipmt2.JPG>
and
<http://www.bspp.org.uk/publications/new-disease-reports/014/2006-65-1.jpg>
Electron micrograph of _Begomovirus_ particles:
<http://www.ncbi.nlm.nih.gov/ICTVdb/WIntkey/Images/em_gemin_2.jpg>
Whiteflies:
<http://www.honolulurosesociety.org/images/Whiteflies-MC_1.jpg>
TSV symptoms on tomato:
<http://www.ipm.ucdavis.edu/PMG/T/D-TO-TBSV-FO.001.html>
Western flower thrips:
<http://www.insectimages.org/images/768x512/4387048.jpg>
Links
Information on tomato leaf curl viral diseases:
<http://www.oisat.org/pests/diseases/viral/leaf_curl__virus.html>,
<http://www.avrdc.org/LC/tomato/tylcv.html>, and <http://www2.dpi.qld.gov.au/health/4250.html>
Current list of species and strains in the tomato leaf curl
group via:
<http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/index.htm>
Genus _Begomovirus_ taxonomy and description:
<http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.029.0.03.htm>
_Begomovirus_ species list:
<http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_gemin.htm#Genus3>
Information on whiteflies:
<http://entomology.ifas.ufl.edu/fasulo/whiteflies/>
and <http://www.uckac.edu/whitefly/faqs_about_whiteflies.htm>
Tobacco streak disease of tomato:
<http://www.ipm.ucdavis.edu/PMG/r783102311.html>
TSV taxonomy and description:
<http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.010.0.02.017.htm>
Thrips information:
<http://www.cals.ncsu.edu/course/ent425/text18/plantvectors.html>
PMoV taxonomy and description:
<http://phene.cpmc.columbia.edu/ICTVdB/00.010.0.02.013.htm>
and <http://md.brim.ac.cn/vide/descr551.htm>
Genus _Ilarvirus_ taxonomy and description:
<http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.010.0.02.htm>
ICTV virus index:
<http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/index.htm>.
- Mod.DHA]
[see also
in the
archive:
New begomovirus, tomato & capsicum - Indonesia: (SW)
20090317.1080 Begomoviruses, multicrop - Cuba: new pathogens
20090303.0866
2008
----
Spearmint disease - India: new begomovirus 20081005.3140 Novel
pathogens, tomato, potato - USA 20080820.2593 Tobacco streak
virus, faba bean - Sudan 20080430.1485 Tomato golden mottle
virus - Mexico: 1st rep, (SLP) 20080310.0977 Squash leaf curl
China virus, pumpkin - Thailand: 1st rep. 20080306.0921
2007
----
Tomato viruses TSWV, TICV - Jordan: 1st reports 20071223.4123
Yellow leaf curl begomoviruses - Netherlands, Taiwan: 1st
reports 20071128.3837 TSV, mungbean - Australia (QLD): 1st
report 20070419.1289 Tomato yellow leaf curl virus - USA
(California, Texas) 20070413.1228 Yellow leaf curl, tomato - USA
(AZ): 1st report 20070226.0694
2006
----
Tobacco streak virus, sunflower - Australia: 1st report
20060731.2118 and additional items in the archives 2005-2001
2001
----
Parietaria mottle ilarvirus, tomato - Europe 20010602.1087] |
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