Does grazing of infected wheat by sheep result in salivary transmission of Wheat streak mosaic virus?

2010 ◽  
Vol 61 (3) ◽  
pp. 247 ◽  
Author(s):  
M. Fahim ◽  
H. Dove ◽  
W. M. Kelman ◽  
L. Ayala-Navarrete ◽  
P. J. Larkin

Research is reported probing the concern of some wheat producers that grazing of early sown, dual-purpose wheat for winter forage may accentuate the spread of Wheat streak mosaic virus (WSMV). In experiments with housed sheep, we investigated whether there were any grounds for this concern. In the first experiment, sheep were allowed to graze heavily virus-infected wheat in trays, followed over a period of 24 h by a series of test trays of healthy wheat. The grazed plants were allowed to recover and new leaves were tested for symptoms and the presence of virus. In total, 2352 test plants were negative for WSMV, assessed through symptoms, ELISA, and RT-PCR. In the second experiment, no WSMV particles (assayed with ELISA) or RNA (assayed by RT-PCR) were detected in any saliva samples collected from sheep 0.5, 7.5, and 24.5 h after being fed heavily virus-infected wheat. Furthermore, these saliva samples, when inoculated onto test wheat seedlings under optimal conditions, failed to transmit the virus. In a third experiment we showed that the urea concentration in sheep saliva is at least two orders of magnitude lower than that required to render WSMV non-infective, and therefore is not responsible for the failure of sheep to transmit the virus. Our data provide no support for the suggestion that grazing sheep spread the WSMV between plants in a grazed wheat crop as a consequence of the grazing process itself.

1964 ◽  
Vol 42 (9) ◽  
pp. 1123-1133 ◽  
Author(s):  
J. T. Slykhuis ◽  
P. L. Sherwood

Endria inimica Say acquired the North American type of wheat striate mosaic virus during periods of 15 minutes or longer on diseased plants held at five constant temperatures ranging from 10 to 33 °C. When infective insects were given inoculation access periods varying from 1 to 4 days at different temperatures, the percentage of test plants infected increased with temperature from 12.5% at 10° to 81.4% at 33 °C. After an acquisition access period of 2 days at 24 °C, insects kept at 8 or 10 °C did not transmit virus, but the percentage of others that transmitted at successively higher temperatures increased from 3.3% at 16 °C to 73.3% at 33 °C. The preinfective period was more than 29 days for insects kept at 16 °C and only 5 days for some kept at 27, 30, and 33 °C. The average preinfective period was 11 days at 20 °C, but decreased to 6.4 days as temperature increased to 33 °C. The percentage of test plants that became infected increased from 0.1% at 16 °C to 44.3%, at 33 °C. Stewart and Ramsey wheat seedlings exposed to infective E. inimica for 2 days did not develop symptoms during a subsequent 60 day period at 10 °C. After the same plants were placed in a greenhouse at 20–25 °C, 26% and 27%, respectively, developed symptoms. The incubation period for symptoms in plants ranged from 17 to more than 62 days at 16 °C. It decreased as temperature increased but varied from 6 to 25 days at 30 °C. Forty-two and 48% of Stewart and Ramsey wheat plants respectively, developed symptoms at 16 °C, and increased to almost 100% for both varieties at 30 and 33 °C. The above results indicate that high temperatures during early summer are prerequisite for severe epidemics of wheat striate mosaic in spring wheat.


2016 ◽  
Vol 31 (1-2) ◽  
pp. 37-44 ◽  
Author(s):  
Dragana Milosevic ◽  
Maja Ignjatov ◽  
Zorica Nikolic ◽  
Ivana Stankovic ◽  
Aleksandra Bulajic ◽  
...  

A total of 86 oilseed rape samples from six crops in different localities were collected during 2014 and analyzed for the presence of Turnip yellows virus (TuYV), Cauliflower mosaic virus (CaMV) and Turnip mosaic virus (TuMV) using commercial double-antibody sandwich (DAS)-ELISA kits. TuYV was serologically detected in 60 collected samples (69.77%), and none of the samples tested were positive for CaMV and TuMV. Six selected TuYV isolates were successfully transmitted by Myzus persicae to three test plants, confirming the infectious nature of the disease. In the selected ELISA-positive samples, the presence of TuYV was further confirmed by RT-PCR and sequencing. A comparison of the obtained sequence with those available in GenBank confirmed the presence of TuYV in oilseed rape samples. An analysis of P0 gene sequence data for a subset of these isolates showed they clustered with the known TuYV and were distinct from Beet western yellows virus (BWYV) isolates.


1963 ◽  
Vol 41 (8) ◽  
pp. 1171-1185 ◽  
Author(s):  
J. T. Slykhuis

Wheat striate mosaic virus from wheat in southeastern Saskatchewan was acquired and transmitted by both nymphs and adults of the leafhopper Endria inimica (Say) collected in Ontario. The preinfective period of leafhoppers varied from 4–6 to 22–24 days after they first fed on diseased plants. Records of serial transmission by individual insects varied greatly. Some insects infected most test plants on which they were given 2-day feeds during 20 to 30 days after the preinfective period, but subsequently they transmitted irregularly. Some transmitted virus for only a few days. Others transmitted intermittently for several weeks. None of the insects infected any plants on which they fed later than 72 days after feeding on diseased plants even though some lived another 10 to 20 days. Two of 25 insects became infective after feeds as short as 30 seconds on diseased plants, but the percentages of infective insects increased to more than 90% as acquisition access times were increased to 2 or more days. All insects from some inbred lines became infective after 3 days on diseased plants, but 45% of the descendants of one non-transmitting female failed to become infective. The inoculation threshold period on Ramsey wheat test plants was 15 minutes, but the percentage of test plants infected increased from 15% to 88.8% as the test access times were increased to 4 days. The incubation period of the virus in Ramsey wheat seedlings varied from 6 to more than 28 days.In tests of host reactions, all durum wheat varieties were highly susceptible to the virus. Several of the hard red spring and winter wheat varieties were highly susceptible and a few others were highly resistant or immune, but most were mildly to moderately susceptible. Most varieties of oats and barley and 10 species of wild annual grasses were moderately susceptible. Mild to moderate symptoms also developed on some of the plants in one or more varieties of Zea mays L., Lolium multiflorum Lam., L. perenne L., and Bromus inermis Leyss. Four varieties of rye tested did not develop symptoms, nor did any plants in 13 species of perennial grasses, including Chloris gayana Kunth, which is susceptible to the Australian wheat striate mosaic virus. E. inimica multiplied on wheat and 14 other annual and 21 perennial grass species, many of which are common on the prairies. There was considerable variation in the reactions to the virus of different plants in the variety Ramsey, but there were no inherent variations detected between the virus isolates used for the experiments. The wheat varieties Cappelle-Desprez and Rescue which are highly susceptible to the European type of wheat striate mosaic virus did not become infected with the Canadian isolates tested.Attempts to transmit the European type of wheat striate mosaic virus with E. inimica failed.


Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 318-323 ◽  
Author(s):  
E. Byamukama ◽  
S. Tatineni ◽  
G. Hein ◽  
J. McMechan ◽  
S. N. Wegulo

Wheat curl mites (WCM; Aceria tosichella) transmit Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), and Wheat mosaic virus (WMoV) to wheat (Triticum aestivum L.) in the Great Plains region of the United States. These viruses can be detected in single, double, or triple combinations in leaf samples. Information on incidence of viruses in WCM at the end of the growing season is scant. The availability of this information can enhance our knowledge of the epidemiology of WCM-transmitted viruses. This research was conducted to determine the frequency of occurrence of WSMV, TriMV, and WMoV in WCM populations on field-collected maturing wheat spikes and to determine differences in WCM densities in three geographical regions (southeast, west-central, and panhandle) in Nebraska. Maturing wheat spikes were collected from 83 fields across Nebraska in 2011 and 2012. The spikes were placed in proximity to wheat seedlings (three- to four-leaf stage) in WCM-proof cages in a growth chamber and on sticky tape. WCM that moved off the drying wheat spikes in cages infested the wheat seedlings. WCM that moved off wheat spikes placed on sticky tape were trapped on the tape and were counted under a dissecting microscope. At 28 days after infestation, the wheat plants were tested for the presence of WSMV, TriMV, or WMoV using enzyme-linked immunosorbent assay and multiplex polymerase chain reaction. WSMV was the most predominant virus detected in wheat seedlings infested with WCM from field-collected spikes. Double (TriMV+WSMV or WMoV+WSMV) or triple (TriMV+ WMoV +WSMV) virus detections were more frequent (47%) than single detections (5%) of TriMV or WSMV. Overall, 81% of the wheat seedlings infested with WCM tested positive for at least one virus. No significant association (P > 0.05) was found between regions for WCM trapped on tape. These results suggest that WCM present on mature wheat spikes harbor multiple wheat viruses and may explain high virus incidence when direct movement of WCM into emerging winter wheat occurs in the fall.


2020 ◽  
Vol 35 (2) ◽  
pp. 117-131
Author(s):  
Ana Vucurovic ◽  
Ivana Stankovic ◽  
Katarina Zecevic ◽  
Branka Petrovic ◽  
Goran Delibasic ◽  
...  

The wheat streak mosaic virus (WSMV), vectored by the wheat curl mite, is globally distributed and threatens wheat production worldwide. Since its first occurrence in Serbia in the 1960s, WSMV presence has not been monitored. In 2019, a total of 62 samples of fi ve wheat cultivars from eight locations in Serbia were collected and tested for the presence of nine common wheat viruses: WSMV, barley yellow dwarf virus-PAV, -MAV, -SGV, and -RMV, cereal yellow dwarf virus-RPV, wheat spindle streak virus, brome mosaic virus, and soil-borne wheat mosaic virus, using individual or multiplex RT-PCR. WSMV was detected in 58.1% of the tested samples in seven wheat crops at five different locations. Species-specific primers failed to detect the presence of the other eight tested viruses. For further confirmation of WSMV, RT-PCR with the WS8166F/WS8909R primers covering the coat protein (CP) gene was carried out for both amplification and sequencing. The amplified product of the correct predicted size (750 bp) derived from four selected isolates, 98-19, 99-19, 102-19 and 120-19, was sequenced and deposited in GenBank (MT461299, MT461300, MT461301 and MT461302, respectively). Serbian WSMV isolates showed very high nucleotide identity (98.16-99.02%) and shared a deletion of triplet codon GCA at nucleotide position 8412- 8414 resulting in deletion of glycine amino acid (Gly2761). Phylogenetic analysis conducted on CP gene sequences revealed the existence of four clades, named A, B, C and D, and one recently introduced clade B1. All Serbian wheat WSMV isolates grouped into clade B together with other European isolates and one isolate from Iran. The results of this study provide the first insight into molecular characterisation of Serbian WSMV isolates, indicating their close relationship with other European isolates and existence of a single genotype in the country. Phylogenetic analysis also confirms the dispersal of WSMV isolates throughout Europe from a single locus.


Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1352-1352 ◽  
Author(s):  
E. Verdin ◽  
P. Gognalons ◽  
C. Wipf-Scheibel ◽  
I. Bornard ◽  
G. Ridray ◽  
...  

In June 2008, tomato (Solanum lycopersicum L.) plants cv. Fer De Lance (De Ruiter Seeds, Bergschenhoek, the Netherlands) grown in greenhouses near Perpignan (southern France) showed growth reduction and necrotic lesions on fruits, stems, and basal parts of the leaves. Tomato torrado virus (ToTV) was suspected on the basis of symptoms and its recent description in Spain (4). Primer set A (3), designed to ToTV RNA-2, was used for reverse transcription (RT)-PCR experiments on RNA extracted from four infected plants and allowed the amplification of a 493-bp fragment. No amplification was observed from healthy plant extracts. The RT-PCR product was directly sequenced (GQ303330) and a BLAST search in GenBank revealed 99.8- and 99.5%-nt identity with Polish (EU563947) and Spanish type strain (DQ388880) isolates of ToTV, respectively. Double-antibody sandwich-ELISA tests were conducted on these four samples to check for the presence of other viruses commonly found in tomato crops in France. Tomato spotted wilt virus, Parietaria mottle virus, Cucumber mosaic virus, Tomato mosaic virus, and Potato virus Y were not detected but Pepino mosaic virus (PepMV) was detected in all samples. ToTV was mechanically transmitted to Physalis floridana but PepMV was not. This plant was used to inoculate healthy tomatoes that served as a ToTV source for further experiments. Mechanical inoculation to test plants showed that Nicotiana benthamiana, N. clevelandii, N. debneyi, N. glutinosa, Capsicum annuum, Solanum melongena, and some tomato cultivars (including Fer De Lance), in which typical necrotic symptoms were observed, were systemically infected by the virus. Isometric particles ~28 nm in diameter were observed by electron microscopy in crude extracts of infected plants negatively stained with 1% ammonium molybdate, pH 7. To confirm ToTV identification, whitefly transmission experiments were performed with Trialeurodes vaporariorum and Bemisia tabaci. Adult whiteflies were placed in cages with infected tomato plants for 1-, 24-, or 48-h acquisition access periods (AAP) before transferring them by groups of ~50 on susceptible tomato plantlets placed under small containers (six plants per AAP). Forty-eight hours later, plants were treated with an insecticide and transferred to an insect-proof containment growth room. Ten days later, RNA preparation from all plants was tested by RT-PCR for the presence of ToTV. No transmission was observed with a 1-h AAP. With a 24-h AAP, transmission to four of six test plants was observed with both whitefly species, while at 48 h, AAP transmission to three and four plants of six was observed with T. vaporariorum and B. tabaci, respectively. Noninoculated control plants were all negative by RT-PCR. These experiments confirm T. vaporariorum and B. tabaci as natural vectors of ToTV as previously described (1,2). ToTV has been already reported in Spain, Poland, Hungary, and Australia, but to our knowledge, this is the first report of ToTV in France. Our detection of ToTV in April 2009 from the same area revealed 7 positive tomato plants of 17 tested. This observation suggests the persistence of the disease in the Perpignan Region. References: (1) K. Amari et al. Plant Dis. 92:1139, 2008. (2) H. Pospieszny et al. Plant Dis. 91:1364, 2007 (3) J. Van der Heuvel et al. Plant Virus Designated Tomato Torrado Virus. Online publication. World Intellectual Property Organization WO/2006/085749, 2006. (4) M. Verbeek et al. Arch. Virol. 152:881, 2007.


2010 ◽  
Vol 165 (2) ◽  
pp. 198-201 ◽  
Author(s):  
J.A. Price ◽  
J. Smith ◽  
A. Simmons ◽  
J. Fellers ◽  
C.M. Rush

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1450-1450 ◽  
Author(s):  
D. P. Di ◽  
Y. L. Zhang ◽  
C. Yan ◽  
T. Yan ◽  
A. H. Zhang ◽  
...  

In the spring of 2014, a survey of viral diseases on wheat (Triticum aestivum L.) was carried out in Hebei Province, China. The samples with virus-like symptoms of dwarfing and flag leaf yellowing were collected in Zhaoxian, Quyang, Anxin, and Luannan. To reproduce the viral symptoms and confirm whether the unknown virus was transmitted by insect vectors, the nymphs of aviruliferous planthopper (Laodelphax striatellus Fallen, Homoptera: Delphacidae) were transferred onto diseased wheat from the field for a 3-day acquisition access period and a 10-day incubation on fresh wheat seedlings, and then were exposed to 2- to 3-leaf stage wheat seedlings of wheat variety Shixin828 for a 3-day inoculation access period. The infected wheat plants developed mosaic symptoms on the young leaves at 7 days post inoculation (dpi), and followed with severe symptoms including stunting, chlorotic spots, and striation along the veins of leaves at around 14 dpi. The infection symptoms were same as in the field but distinct from wheat infected with Rice black streaked dwarf virus (RBSDV) or Northern cereal mosaic virus (NCMV). For further confirmation, total RNA was extracted from the symptomatic wheat leaves, and NCMV specific primers, NCMV-PF/NCMV-PR (5′-ATGGATAAGAAAGCAAGTGGA-3′/5′-TTAAAAGTCGGCATACGGGTC-3′) and RBSDV specific primers, S10-F/S10-R (5′-TTACCCAACATCACGCAACT-3′/5′-GAGCAGGAACTTCACGACAAC-3′) were used for amplification of sequences of phosphoprotein and coat protein genes, respectively. Neither RBSDV nor NCMV were present in the symptomatic tissue according to the RT-PCR assay (4). Tissues derived from symptomatic wheat leaves were fixed and embedded in Spurr's resin and used for ultra-thin sectioning and transmission electron microscopy observations, revealing large amounts of Rhabdovirus-like particles in the cytoplasm. The identified particles were about 315 to 353 × 46 to 57 nm, similar in size to Barley yellow striate mosaic virus (BYSMV), a member of the genus Cytorhabdovirus reported from Italy (2). The specific primer pair (5′-ACTAAGGGGGTACTCCGACC-3′ and 5′-CTGATCTGCTTTGAGGGGCA-3′) was designed based on the reported polymerase (L) gene sequence of BYSMV isolate Zanjan-1 (GenBank Accession No. FJ665628) (1), and used for the BYSMV detection by RT-PCR. A single bright band of the expected size (~500 bp) was obtained from total RNA extracted from the plants exhibiting symptoms in the greenhouse. No such band was amplified from asymptomatic plants, while 15 out of 23 field samples also produced the same 500-bp products in RT-PCR. PCR products from three virus-positive field samples were sequenced directly and the sequences were submitted to GenBank (KM052176, KM052177, and KM052178). BLAST search showed that the sequences shared 96 to 97% nucleotide identity with the polymerase L gene sequence of BYSMV isolate Zanjan-1, whereas only 73 to 75% identity with NCMV (AB030277 and GU985153) (1,3,5). To our knowledge, this is the first report of BYSMV occurrence on wheat in China. References: (1) R. Almasi et al. J. Phytopathol. 158:351, 2010. (2) A. Appiano et al. Cytol. 6:105, 1974. (3) H. C. Chen et al. Sci. Agric. Sinica 3:64, 1980. (4) X. F. Duan et al. Acta Phytopathol. Sinica 40:337, 2010. (5) F. Tanno et al. Arch. Virol. 145:1373, 2000.


Plant Disease ◽  
2021 ◽  
Author(s):  
Bidisha Chanda ◽  
Andrea Gilliard ◽  
Namrata Jaiswal ◽  
Kai-Shu Ling

Tomato (Solanum lycopersicum L.) is one of the most important vegetables in the world. However, tomato is also susceptible to many viral diseases. Several tobamoviruses, including tomato mosaic virus (TMV), tomato mottle mosaic virus (ToMMV) and tomato brown rugose fruit virus (ToBRFV), are highly contagious pathogens, which could result in significant economic losses if not controlled effectively. Tobamoviruses have been managed relatively well with broad adaptation of tomato cultivars with resistance genes. However, recent emergence of ToBRFV was shown to breakdown resistance conferred by the common resistance genes, resulting in serious outbreaks in many countries in Asia, Europe, and North America. The objective of this study was to conduct a comparative analysis of biological properties, including host range and disease resistance of ToMV, ToMMV and ToBRFV. Results showed that despite many similarities in the host range, there were some unique host plant responses for each of the three viruses. In a comparative evaluation of disease resistance using the same tomato cultivars with or without Tm-22 gene, there was a striking difference in responses from tomato plants with Tm-22 gene inoculated with ToBRFV, ToMV or ToMMV. Whereas these test plants were largely resistant to ToMV or ToMMV infection, all test plants were susceptible to ToBRFV. Further, for ToBRFV detection, a sensitive and reliable multiplex real-time RT-PCR assay using TaqMan probe with an internal 18S rRNA control was also developed. With simple modifications to RNA extraction and seed soaking, real-time RT-PCR could consistently detect the virus in single infested seed in varied levels of contamination, suggesting its usefulness for seed health assay.


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