scholarly journals Cross Protection by Strains of Tomato Spotted Wilt Virus and a New Theory to Explain It

1954 ◽  
Vol 7 (4) ◽  
pp. 415 ◽  
Author(s):  
RJ Best

A study of interference between strains of tomato spotted wilt virus in tomato plants has revealed that the mUd strain C1 protects plants against the severe strain A whether this is inoculated before or after systemic symptoms of the mild strain appear (10 and 20 days respectively).

2020 ◽  
Vol 11 ◽  
Author(s):  
Saeid Tabein ◽  
Marco Jansen ◽  
Emanuela Noris ◽  
Anna Maria Vaira ◽  
Daniele Marian ◽  
...  

Tomato spotted wilt virus (TSWV) is a devastating plant pathogen, causing huge crop losses worldwide. Unfortunately, due to its wide host range and emergence of resistance breaking strains, its management is challenging. Up to now, resistance to TSWV infection based on RNA interference (RNAi) has been achieved only in transgenic plants expressing parts of the viral genome or artificial microRNAs targeting it. Exogenous application of double-stranded RNAs (dsRNAs) for inducing virus resistance in plants, namely RNAi-based vaccination, represents an attractive and promising alternative, already shown to be effective against different positive-sense RNA viruses and viroids. In the present study, the protection efficacy of exogenous application of dsRNAs targeting the nucleocapsid (N) or the movement protein (NSm) coding genes of the negative-sense RNA virus TSWV was evaluated in Nicotiana benthamiana as model plant and in tomato as economically important crop. Most of the plants treated with N-targeting dsRNAs, but not with NSm-targeting dsRNAs, remained asymptomatic until 40 (N. benthamiana) and 63 (tomato) dpi, while the remaining ones showed a significant delay in systemic symptoms appearance. The different efficacy of N- and NSm-targeting dsRNAs in protecting plants is discussed in the light of their processing, mobility and biological role. These results indicate that the RNAi-based vaccination is effective also against negative-sense RNA viruses but emphasize that the choice of the target viral sequence in designing RNAi-based vaccines is crucial for its success.


2020 ◽  
Vol 11 ◽  
Author(s):  
Punya Nachappa ◽  
Jean Challacombe ◽  
David C. Margolies ◽  
James R. Nechols ◽  
Anna E. Whitfield ◽  
...  

Several plant viruses modulate vector fitness and behavior in ways that may enhance virus transmission. Previous studies have documented indirect, plant-mediated effects of tomato spotted wilt virus (TSWV) infection on the fecundity, growth and survival of its principal thrips vector, Frankliniella occidentalis, the western flower thrips. We conducted thrips performance and preference experiments combined with plant gene expression, phytohormone and total free amino acid analyses to determine if systemically-infected tomato plants modulate primary metabolic and defense-related pathways to culminate into a more favorable environment for the vector. In a greenhouse setting, we documented a significant increase in the number of offspring produced by F. occidentalis on TSWV-infected tomato plants compared to mock-inoculated plants, and in choice test assays, females exhibited enhanced settling on TSWV-infected leaves. Microarray analysis combined with phytohormone signaling pathway analysis revealed reciprocal modulation of key phytohormone pathways under dual attack, possibly indicating a coordinated and dampening defense against the vector on infected plants. TSWV infection, alone or in combination with thrips, suppressed genes associated with photosynthesis and chloroplast function thereby significantly impacting primary metabolism of the host plant, and hierarchical cluster and network analyses revealed that many of these genes were co-regulated with phytohormone defense signaling genes. TSWV infection increased expression of genes related to protein synthesis and degradation which was reflected in the increased total free amino acid content in virus-infected plants that harbored higher thrips populations. These results suggest coordinated gene networks that regulate plant primary metabolism and defense responses rendering virus-infected plants more conducive for vector colonization, an outcome that is potentially beneficial to the vector and the virus when considered within the context of the complex transmission biology of TSWV. To our knowledge this is the first study to identify global transcriptional networks that underlie the TSWV-thrips interaction as compared to a single mechanistic approach. Findings of this study increase our fundamental knowledge of host plant-virus-vector interactions and identifies underlying mechanisms of induced host susceptibility to the insect vector.


2003 ◽  
Vol 38 (1) ◽  
pp. 127-136 ◽  
Author(s):  
C. Chaisuekul ◽  
D. G. Riley ◽  
H. R. Pappu

Thrips (Thysanoptera: Thripidae) and mechanical transmissions of tomato spotted wilt virus (TSWV) to tomato (Lycopersicon esculentum Mill, cv. ‘Sunny Hybrid’) were investigated relative to plant age at the time of inoculation. In 1999, thrips and mechanical transmissions were compared between plants at 7, 14 and 28 d after germination under field exclusion cages. In 2000, thrips transmission was evaluated in plants at 7, 14, 21, 28, 35 and 42 d after germination, and mechanical transmission was evaluated in plants at 14, 21, 28, 35, 42 and 49 d after germination. Subsamples of thrips from flowers of TSWV-infected tomato used in 1999 transmission consisted of 59% Frankliniella occidentalis (Pergande), 34% F. tricici (Fitch), and subsamples of thrips collected from onion used in 2000 transmission consisted of 78% F. occidentalis and 19% F. fusca (Hinds). There was significant yield reduction resulting from early transmission of TSWV in the mechanical transmission test in 2000 (P= 0.008), but not in thrips transmission test in 2000 (P= 0.62). A reduction in the percent of TSWV-damaged fruit in late transmission was significant in the thrips transmission test (P = 0.04) but not in the mechanical transmission test (P= 0.25) in 2000. Lag time from virus transmission to symptom development or to a positive ELISA test was highly correlated to TSWV damaged fruit (P < 0.001 and P < 0.001, respectively) in the mechanical transmission test in 2000. The lag time of a positive ELISA in the thrips transmission test in 2000 correlated with the percentage of TSWV-damaged fruit (P = 0.009). In summary, early infection of TSWV to tomato plants resulted in lower yield and a higher percentage of TSWV-damaged fruits than late infection.


Plant Disease ◽  
2006 ◽  
Vol 90 (9) ◽  
pp. 1150-1155 ◽  
Author(s):  
B. Mandal ◽  
H. R. Pappu ◽  
A. S. Csinos ◽  
A. K. Culbreath

Spotted wilt disease, caused by Tomato spotted wilt virus (TSWV), is an economically important disease in peanut, pepper, tobacco, and tomato in the southeastern United States. However, very little is known about the biological variability existent in the virus population. Fourteen isolates of TSWV collected in Georgia were evaluated for symptom severity. The majority of the isolates produced severe systemic necrosis. One mild (GATb-1) and one severe (GAL) isolate were further examined because of the distinct differences in their virulence and symptomatology on tobacco. GATb-1 caused a few chlorotic spots and mild systemic symptoms, whereas GAL produced a large number of local lesions and severe systemic necrosis. Distinct differences in the response of selected commercial cultivars of peanut, tobacco, and tomato to GATb-1 and GAL infection were observed. GAL was lethal to a widely grown tobacco cultivar, K326. Georgia Green, a field resistant peanut cultivar, and C11-2-39, a breeding line with the highest level of known resistance to TSWV, were more susceptible to GAL than to GATb-1. BHN 444, a newly released TSWV-resistant tomato cultivar, showed a resistant reaction, whereas Stiletto, a newly released TSWV-resistant pepper cultivar, was susceptible to both GATb-1 and GAL isolates. Information on the biological diversity of TSWV may be useful in developing more durable TSWV-resistant crops.


HortScience ◽  
1999 ◽  
Vol 34 (4) ◽  
pp. 634-637 ◽  
Author(s):  
M.J. Díez ◽  
S. Roselló ◽  
F. Nuez ◽  
J. Costa ◽  
M.S. Catalá ◽  
...  

Seedlings of three tomato (Lycopersicon esculentum Mill.) cultivars [`RDD', carrier of the Sw5 gene, which confers resistance to tomato spotted wilt virus (TSWV); `Pitihué', tolerant to the virus; and the susceptible cultivar Rutgers] were placed at the four- to five-leaf stage in cages containing a population of viruliferous thrips (Frankliniella occidentalis Perg.), and remained there for 0, 7, or 15 days. Plants were subsequently transplanted either into the open field or in tunnels protected with a mesh of 14 × 10 threads/cm. Systemic symptoms and number of dead plants were recorded and enzymelinked immunosorbent assays (ELISA) were performed. `Rutgers' exhibited severe systemic symptoms regardless of treatment and a high number of plants died. The level of infected plants remained low when protective measures were applied to seedlings of `Pitihué' and acceptable yields were obtained. In open air cultivation, where seedling infection was severe, <20% of `RDD' plants became infected and high yields were obtained; protected cultivation did not reduce yield. Although the percentage of infected plants was higher when cultivated under mesh, the yield of all three cultivars was greater than in the open field. The environment created under mesh stimulated growth, neutralizing the effect of the infection.


2018 ◽  
Vol 40 (4) ◽  
pp. 580-586 ◽  
Author(s):  
Aleksandra Zarzyńska-Nowak ◽  
Beata Hasiów-Jaroszewska ◽  
Grażyna Korbecka-Glinka ◽  
Marcin Przybyś ◽  
Natasza Borodynko-Filas

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