Tomato Spotted Wilt Virus Disease Research Articles

Study on the automatic detection of pepper TSWV disease based on ResNet

This study focuses on the development of a binary classification model for Tomato Spotted Wilt Virus (TSWV) recognition in peppers. A diverse dataset is created for model training, which incorporates TSWV-infected pepper imagery with varying infection severity and regions of different sizes and resolution. The model is trained based on ResNet-18 architecture, resulting in excellent performance of metrics with scores reaching 0.990. Thus, the developed model may have applicational potential for pepper TSWV recognition in real-life conditions.

An Isoform of the Eukaryotic Translation Elongation Factor 1A (eEF1a) Acts as a Pro-Viral Factor Required for Tomato Spotted Wilt Virus Disease in Nicotiana benthamiana

The tripartite genome of the negative-stranded RNA virus Tomato spotted wilt orthotospovirus (TSWV) is assembled, together with two viral proteins, the nucleocapsid protein and the RNA-dependent RNA polymerase, into infectious ribonucleoprotein complexes (RNPs). These two viral proteins are, together, essential for viral replication and transcription, yet our knowledge on the host factors supporting these two processes remains limited. To fill this knowledge gap, the protein composition of viral RNPs collected from TSWV-infected Nicotiana benthamiana plants, and of those collected from a reconstituted TSWV replicon system in the yeast Saccharomyces cerevisiae, was analysed. RNPs obtained from infected plant material were enriched for plant proteins implicated in (i) sugar and phosphate transport and (ii) responses to cellular stress. In contrast, the yeast-derived viral RNPs primarily contained proteins implicated in RNA processing and ribosome biogenesis. The latter suggests that, in yeast, the translational machinery is recruited to these viral RNPs. To examine whether one of these cellular proteins is important for a TSWV infection, the corresponding N. benthamiana genes were targeted for virus-induced gene silencing, and these plants were subsequently challenged with TSWV. This approach revealed four host factors that are important for systemic spread of TSWV and disease symptom development.

Continuous Time Individual-Level Models of Infectious Disease: Package EpiILMCT

This paper describes the R package EpiILMCT, which allows users to study the spread of infectious disease using continuous time individual level models (ILMs). The package provides tools for simulation from continuous time ILMs that are based on either spatial demographic, contact network, or a combination of both of them, and for the graphical summarization of epidemics. Model fitting is carried out within a Bayesian Markov Chain Monte Carlo framework. The continuous time ILMs can be implemented within either susceptible-infected-removed (SIR) or susceptible-infected-notified-removed (SIN R) compartmental frameworks. As infectious disease data is often partially observed, data uncertainties in the form of missing infection times - and in some situations missing removal times - are accounted for using data augmentation techniques. The package is illustrated using both simulated and an experimental data set on the spread of the tomato spotted wilt virus disease.

Epidemiology of tomato spotted wilt virus in Chrysanthemum morifolium in South Korea and its management using a soil-dwelling predatory mite (Stratiolaelaps scimitus) and essential oils

Tomato spotted wilt virus (TSWV) is one of most destructive viruses in vegetable and ornamental crop production worldwide. A greenhouse survey to determine the incidence of TSWV in Chrysanthemummorifolium Ramat. was conducted during the 2018 and 2019 growing seasons in South Korea. TSWV was detected using a double antibody sandwich-enzyme-linked immunosorbent assay, and positive results were confirmed using reverse transcription-polymerase chain reaction (RT-PCR). A total of 1569 chrysanthemum plants (70.77 %) tested positive for TSWV among 2217 symptomatic chrysanthemum plants collected from 16 greenhouses. In addition, 116 thrips (72.96 %; Frankliniella occidentalis Pergande) that contained TSWV were identified using RT-PCR from a total of 159 thrips collected from the greenhouses during the survey. A high incidence of viruliferous thrips may have played a role in TSWV occurrence in the chrysanthemum greenhouse. To develop a novel approach for thrips management, the effectiveness of a soil-dwelling predatory mite (Stratiolaelaps scimitus Berlese) and 45 essential oils (as bio-insecticides applied via foliar treatment) was assayed. Four essential oils (cinnamon oil, cinnamon bark oil, oregano oil, and thyme oil) were shown to be significantly toxic to eggs, larvae, and adults of F. occidentalis. For the combined treatment, individuals of S. scimitus (60/m2) were placed on the soil in the chrysanthemum greenhouses. Then, a mixture of the four essential oils was applied as foliar treatment at 4-day intervals. A very low incidence of thrips emerged as adults from the soil (1.2–8.5 %) in the combined treatment in the chrysanthemum greenhouses when surveyed twice per month, compared with the non-treated control or when conventional insecticide sprays were applied. The incidence of TSWV (0.93 %) in chrysanthemum treated with S. scimitus in conjunction with the mixture of four essential oils decreased significantly compared with that treated with chemical insecticides (32.05 %) and in the non-treated controls (84.85 %). Our findings contribute to the development of novel strategies to control TSWV disease in chrysanthemum plants; notably, the control of F. occidentalis using eco-friendly insecticides appears promising.

Ozone treatments activate defence responses against Meloidogyne incognita and Tomato spotted wilt virus in tomato.

Ozonated water (O3 wat) soil drench and/or foliar spray applications were evaluated for their potential to control the root-knot nematode Meloidogyne incognita (RKN) and the airborne pathogen Tomato spotted wilt virus (TSWV) in tomato. We investigated how O3 wat modulates the salicylic acid/jasmonic acid/ethylene (SA/JA/ET) signalling network in the host, locally and systemically, to induce resistance to nematode and virus. The application as soil drench was effective in reducing the number of galls and egg masses, but did not reduce the incidence and severity of TSWV infection. Conversely, O3 wat applied by foliar spray decreased TSWV disease incidence and severity (-20%), but was not able to control M. incognita infection. SA-related genes were generally upregulated in both locally treated and systemically reached tissues, showing a positive action of the O3 wat treatment on SA signalling. Neither O3 wat application method significantly altered JA-related gene expression in either direction. ET-related genes were differentially regulated by root or leaf treatments, indicating that O3 wat may have different effects on ET-mediated signalling in different organs. JA/ET/SA related pathways were differentially modulated by O3 wat in the presence of either RKN or TSWV. O3 wat had a higher efficacy when applied directly to organs challenged by the pathogens, although it was potentially able to stimulate defence responses through the activation of SA signalling. Owing to its safety and effectiveness in controlling nematode and virus infections, O3 wat can be considered as a possible alternative tool for sustainable disease management practices. © 2019 Society of Chemical Industry.

Erratum to: Complete sequence of three different biotypes of tomato spotted wilt virus (wild type, tomato Sw-5 resistance-breaking and pepper Tsw resistance-breaking) from Spain.

Tomato spotted wilt virus (TSWV) occurs worldwide and causes production losses in many important horticultural crops such as tomato and pepper. Breeding resistant cultivars has been the most successful method so far for TSWV disease control, but only two genes have been found to confer resistance against a wide spectrum of TSWV isolates: Sw-5 in tomato and Tsw in pepper. However, TSWV resistance-breaking isolates have emerged in different countries a few years after using resistant cultivars. In this paper, we report the first complete nucleotide sequences of three Spanish TSWV isolates with different biotypes according to their abilities to overcome resistance: LL-N.05 (wild type, WT), Pujol1TL3 (Sw-5 resistance breaking, SBR) and PVR (Tsw resistance-breaking, TBR). The genome of these TSWV isolates consisted of three segments: L (8913-8914 nt), M (4752-4825 nt) and (S 2924-2961 nt). Variations in nucleotide sequences and genomic RNA lengths among the different virus biotypes are reported here. Phylogenetic analysis of the five TSWV open reading frames showed evidence of reassortment between genomic segments of LL-N.05 and Pujol1TL3, which was supported by analysis with different recombination-detecting algorithms.

Complete sequence of three different biotypes of tomato spotted wilt virus (wild type, tomato Sw-5 resistance-breaking and pepper Tsw resistance-breaking) from Spain.

Tomato spotted wilt virus (TSWV) occurs worldwide and causes production losses in many important horticultural crops such as tomato and pepper. Breeding resistant cultivars has been the most successful method so far for TSWV disease control, but only two genes have been found to confer resistance against a wide spectrum of TSWV isolates: Sw-5 in tomato and Tsw in pepper. However, TSWV resistance-breaking isolates have emerged in different countries a few years after using resistant cultivars. In this paper, we report the first complete nucleotide sequences of three Spanish TSWV isolates with different biotypes according to their abilities to overcome resistance: LL-N.05 (wild type, WT), Pujol1TL3 (Sw-5 resistance breaking, SBR) and PVR (Tsw resistance-breaking, TBR). The genome of these TSWV isolates consisted of three segments: L (8913-8914 nt), M (4752-4825 nt) and (S 2924-2961 nt). Variations in nucleotide sequences and genomic RNA lengths among the different virus biotypes are reported here. Phylogenetic analysis of the five TSWV open reading frames showed evidence of reassortment between genomic segments of LL-N.05 and Pujol1TL3, which was supported by analysis with different recombination-detecting algorithms.

Stem Rot (White Mold) and Tomato Spotted Wilt Resistance among Peanut Genotypes

ABSTRACT Stem rot, also known as white mold (WM), caused by Sclerotium rolfsii Sacc., and tomato spotted wilt, caused by Tomato spotted wilt virus (TSWV), are two major disease problems in Georgia peanut (Arachis hypogaea L.) production. Current fungicides for stem rot control are very effective but expensive, and insecticides usually have little effect on TSWV, which is transmitted by thrips. Consequently, the objective of this study was to evaluate different peanut genotypes for resistance to both of these pathogens. Field test evaluations were conducted for four consecutive years (2010-13) at a site on the agronomy research farm near the Coastal Plain Experiment Station which has a long history of continuous peanut production and a high incidence of stem rot (WM) and TSWV. Results from these field tests showed significant differences among the peanut genotypes evaluated for combined resistance to both diseases. Several genotypes showed low TSWV incidence at mid-season and mid-to-late season. However by late season and after digging, the best combination of stem rot (WM) and TSWV disease resistance and highest consistent yield over years was in the runner-type peanut cultivar ‘Georgia-12Y’, along with ‘York’, ‘Georgia-07W’, and ‘Georgia-10T’.

Registration of ‘Georgia‐09B’ Peanut

‘Georgia‐09B’ (Reg. No. CV‐110, PI 658595) is a new high‐yielding, high‐oleic, Tomato spotted wilt virus (TSWV)‐resistant, medium‐seeded, runner‐type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) cultivar that was released by the Georgia Agricultural Experiment Stations in 2009. It was developed at the University of Georgia, Coastal Plain Experiment Station, Tifton, GA. Georgia‐09B originated from the first backcross (BC1) made between ‘Georgia Green’ and F2:3 (Georgia Green × GA 942004). Pedigree selection was practiced within the early segregating generations. Performance testing began in the BC1F4:6 generation with the advanced pure‐line selection, GA 032902, the experimental designation of Georgia‐09B. During three years (2006–2008) averaged over 27 multiple location tests in Georgia, Georgia‐09B had significantly less TSWV disease incidence, higher yield and percent total sound mature kernels (TSMK) grade, larger seed size, and greater dollar value return per hectare compared to the check cultivar, Georgia Green. Georgia‐09B has also showed significantly higher TSMK percentage and dollar value than ‘York’, ‘AT‐3085RO’, and ‘McCloud’ and was found to have a medium runner seed size as compared to the larger high‐oleic, runner‐type check cultivars, ‘Florida‐07’, AT‐3085RO, and McCloud. Georgia‐09B combines the excellent roasted flavor of Georgia Green with the high‐oleic trait for longer shelf life and improved oil quality of peanut and peanut products.

Reduction of Tomato spotted wilt virus on Table Tomatoes in Greenhouses by Soil Fumigation

Tomato spotted wilt virus (TSWV) has occurred on fields annually disease occurrence rates were 73.3% in 2005, 53.3% in 2006 and 41.6% in 2007 at Anyang area in Gyeonggi Province. Seasonal occurrence pattern of TSWV showed a dramatic increase from 8.7% in late May to 30.1 % in early June in 2007 at Anyang area, coincided with the high population of a thrip, Frank-liniella occidentalis at that time. The rate of viruliferous thrips with TSWV on lettuce and red pepper was 20.2% and 52.1%, respectively, in greenhouses. Dazomat, soil fumigation pesticide, reduced TSWV disease incidence drastically on table tomato as treatment the chemical into the soil with humidity in early spring in 2006 and 2007. Spraying insecticide periodically after treatment with Dazomat was more effective to control TSWV than spraying if on plants or applying into the soil of the insecticide during growing season. Control efficiency through treatments both of the soil fumigation and of spraying insecticide was significantly high with 85.3% in 2006 and 87.8% in 2007. Removing the potential vector from the soil of TSWV infested area can be an effective strategy for reducing TSWV disease.

Variety, mulch and stage of inoculation effects on incidence of tomato spotted wilt virus disease in cucumber (Cucumis sativus L.)

Tomato spotted wilt virus (TSWV) vectored by thrips is one of the major diseases affecting cucumber yield. Control of thrips is an underlying factor in its management. A study was conducted to determine the effect of time of inoculation, variety and mulch on disease incidence. Four varieties were inoculated with TSWV at cotyledon, 3 – 4 leaf and flower bud stages in a RCBD experiment replicated four times in a greenhouse. In the field, a 2×8 factorial design where two cucumber varieties were raised on seven types of mulches (red, yellow, silver, clear, black, white, and straw) with unmulched plots as controls was used. Variety Marketer was more tolerant to the disease compared to other varieties. Most varieties were generally tolerant to TSWV at cotyledonous but susceptible at 3 – 4 leaf and flower bud stages. Silver and clear mulches significantly suppressed thrip populations, yield and quality under field conditions.

Registration of ‘Georgia‐08V’ Peanut

‘Georgia‐08V’ (Reg. No. CV‐105, PI 655573) is a new high‐yielding, high‐oleic, Tomato spotted wilt virus (TSWV)–resistant, large‐seeded, virginia‐type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) cultivar released by the Georgia Agricultural Experiment Stations in 2008. It was developed at the University of Georgia, Coastal Plain Experiment Station, Tifton, GA. Georgia‐08V originated from a cross made between ‘C‐99R’ × ‘Georgia Hi‐O/L’. Pedigree selection was practiced within the F2, F3, and F4 generations. Performance testing began in the F4:6 generation with the advanced pure‐line selection, GA 012535, the experimental designation of Georgia‐08V. Averaged over 38 multilocation tests conducted in Georgia during 2004 to 2007, Georgia‐08V had significantly less TSWV disease incidence, higher yield and percentage extra‐large kernels (ELK), larger seed size, and greater dollar value return per hectare compared with the check cultivars, Gregory, Perry, and NC‐V 11. Georgia‐08V also had significantly higher yield, ELK percentage, and dollar value than Georgia Hi‐O/L and was also found to have the largest seed size of all of the virginia‐type cultivars tested, including ‘Georgia‐05E’.

Cropping system influences Tomato spotted wilt virus disease development, thrips population and yield of tomato (Lycopersicon esculentum)

AbstractYield of tomato is limited by many diseases including Tomato spotted wilt virus disease. This study was conducted in the field at Kenya Agriculture Research Institute Njoro, Kenya, in 2004 and 2006 to determine the effect of intercropping on disease development, thrips population and yield of tomato variety Cal J grown under four intercrop systems involving kale, onion, maize and sole tomato. The experimental design was a Randomised Complete Block Design (RCBD) replicated three times. Disease scores on tomato–maize differed significantly from tomato–kale and tomato–onion in both years of the study. Maize cropping system had a low significant thrips population from the other cropping systems. Tomato–maize intercrop produced the lowest fruit weights and marketable yield in 2004 and 2006, while yield of onion, kale and maize in intercrops were not significantly different from their monocrops. Land equivalent ratio was >1 in all the cropping systems.

INFLUENCE OF GIBBERELLIC ACID (GA3) AND PLANTING DISTANCE ON GLOBE ARTICHOKE CULTIVARS AFFECTED BY TOMATO SPOTTED WILT VIRUS (TSWV)

The aim of this study was to know the earliness and yield of different cultivar of artichoke after GA3 application as a substitute of vernalization, as soon as planting distance answer. The possible infection with tomato spotted wilt virus (TSWV) also was considered. Two seed propagated cultivar (Lorca, A-106) and another one of vegetative propagation de Tudela were tried. The results show that GA3 treatments, especially 25 ppm dose, are very effective to promote earliness in “Blanca de Tudela” cultivar, whereas the action was smaller in seed propagated cultivars. The increase of planting distance raised earliness of cv. Blanca de Tudela, whereas the effect was smaller in Lorca and A-106 cultivars. In the trial conditions cv. A-106 was the most sensible to TSWV disease.

Intrinsic Rate of Increase of Frankliniella fusca (Thysanoptera: Thripidae) on Peanuts

Frankliniella fusca (Hinds) is a thrips species of economic importance that produces direct injury to leaves and is a vector of the tomato spotted wilt virus. The intrinsic growth rate of increase and the effect of two initial densities of immature F. fusca on immature survivorship and adult emergence was determined by enclosing adult or immature thrips on peanut leaflets. The number of emerging immature thrips was 14.5 per female. Immature emergence began in 7 d with a peak of emergence (67%) between 8 and 9 d. No males emerged. Females reached maturity 11.7 d after emergence. The gross value of the intrinsic growth rate of increase was 0.500 and the value determined by iteration was 0.405. Total emergence of cohorts with smaller initial numbers of immatures (32 larvae per bag) was significantly higher than of larger cohorts (117 larvae per bag). Under high population densities, reduced survivorship may assure that enough resources are available for successful reproduction of some adults. Our studies reveal that F. fusca has the potential for high population increases in peanut which may favor persistence and spread of tomato spotted wilt virus disease.