Diversity of Thrips Species and Vectors of Tomato Spotted Wilt Virus in Tomato Production Systems in Kenya

2015 ◽  
Vol 108 (1) ◽  
pp. 20-28 ◽  
Author(s):  
I. Macharia ◽  
D. Backhouse ◽  
R. Skilton ◽  
E. Ateka ◽  
S.-B. Wu ◽  
...  
2003 ◽  
Vol 38 (4) ◽  
pp. 660-668 ◽  
Author(s):  
R. M. McPherson ◽  
R. J. Beshear ◽  
W. C. Johnson ◽  
N. Martinez-Ochoa ◽  
M. L. Wells

The tobacco thrips, Frankliniella fusca (Hinds), is an economic pest of flue-cured tobacco because it vectors tomato spotted wilt tospovirus. Other species of thrips are also vectors of spotted wilt in tobacco, including the western flower thrips, F. occidentalis (Pergande). This study examined the presence of thrips species on alternate plant hosts associated with the tobacco farmscape and surrounding area. Weed hosts were sampled from December through April from 1998 through 2001 to assess which plants provide suitable refuge and nutrients for thrips survival, reproduction, and spotted wilt infection. Thrips were identified to species and confirmed as potential vectors of spotted wilt by using ELISA to test for the presence of a non-structural tomato spotted wilt virus protein. Wild radish (Raphanus raphanistrum L.), broomsedge (Andropogon virginicus L.), and narrowleaf vetch (Vicia sativa L. subsp. nigra (L.) Ehrh.) are common late-winter weeds in the farmscape that harbor spotted wilt vectors. Cutleaf evening primrose, Oenethera laciniata Hill, and volunteer soybean, Glycine max(L.) Merrill, also were hosts of spotted wilt vectors in the tobacco farmscape. Numerous other weed hosts were present in the tobacco farmscape but either had no thrips collected from them or thrips were not confirmed as potential spotted wilt vectors from these host plants. Several other plants near the tobacco farmscape also were infected with spotted wilt, and three of these host plants, common chickweed (Stellaria media (L.) Cyrillo), carrot (Daucus carota L.), and flowering dogwood (Cornus florida L.) had confirmed vectors (ELISA) collected from them. Henbit (Lamium amplexicaule L.), wild radish, cutleaf evening primrose, narrowleaf vetch, carrot, curly dock (Rumex crispus L.), red sorrel (Rumex acetosella L.), and common chickweed were confirmed as positive plant hosts in this study for spotted wilt using ELISA. Frankliniella fusca appears to be the most abundant thrips vector on these alternate plant hosts and is the predominate thrips species collected on the flue-cured tobacco, Nicotiana tabacum L. However, F. occidentalis, Haplothrips graminis Hood, and Chirothrips spp. also were confirmed in this study to be potential vectors in the tobacco farmscape. Weed hosts in the farmscape appear to be influential as refuge and nutrients for vectors and an innoculant source of tomato spotted wilt virus in the flue-cured tobacco farmscape.


2001 ◽  
Vol 91 (12) ◽  
pp. 1149-1155 ◽  
Author(s):  
Jun Ohnishi ◽  
Leandra M. Knight ◽  
Daijirou Hosokawa ◽  
Ichiro Fujisawa ◽  
Shinya Tsuda

If acquisition access feeding (AAF) is first given after adult eclosion, none of the nine thrips species able to serve as tospovirus vectors can become infective. The previous cellular investigations of this phenomenon, carried out only in Frankliniella occidentalis, suggested that infectivity was prevented because the type member of the tospoviruses, Tomato spotted wilt virus (TSWV), was unable to enter the midgut of adult thrips. The present study extends a cellular view of tospovirus—thrips interactions to a species other than the western flower thrips, F. occidentalis. Our findings show that TSWV enters and replicates within the midgut of adult Thrips setosus, but does not infect cells beyond the midgut epithelia. After AAF as adult, TSWV replicated in T. setosus midgut cells as indicated by significant increases in nucleocapsid (N) protein detected by double-antibody sandwich enzyme-linked immunosorbent assay, and the presence of inclusions containing the S RNA-encoded nonstructural and N proteins revealed by microscopic observations. Electron microscopic observations of adult insects showed that no infection occurred in cells beyond the midgut epithelia, and insects subsampled from the same cohorts could not transmit TSWV. In contrast, electron microscopy observations of larval T. setosus revealed that TSWV infected the midgut and muscle cells, and adult insects developing from these cohorts had infected salivary glands and were able to transmit TSWV. Mature virions were observed only in the salivary glands of adults developing from infected larvae. Our findings suggest that the barrier to infectivity in T. setosus adults differs from that shown for F. occidentalis adults.


2002 ◽  
Vol 92 (7) ◽  
pp. 729-733 ◽  
Author(s):  
F. M. de Assis Filho ◽  
R. A. Naidu ◽  
C. M. Deom ◽  
J. L. Sherwood

Transmission of Tomato spotted wilt virus (TSWV) is dependent on virus uptake in the midgut prior to virus movement to the salivary glands. Replication of TSWV in the alimentary canal of tobacco thrips (TT, Frankliniella fusca) and western flower thrips (WFT, F. occidentalis) was investigated by immunolocalization of the nonstructural protein (NSs) encoded by the small RNA of TSWV and fluorescence microscopy. Analysis of cohorts during development from larva to adults following virus acquisition by first instar larva indicated that virus replication followed a specific time-course pattern in the foregut, regions of the midgut, salivary glands, and ligaments between the midgut and salivary glands. Initial virus replication occurred only in epithelial cells of midgut-1 but, upon infection of muscle cells, the virus moved to the midgut-2, foregut, midgut-3, and salivary glands. The ligaments between the midgut and salivary glands appeared to be a route for virus to invade the salivary glands. No virus replication was observed in the hindgut, Malpighian tubules, or tubular salivary glands. The dynamics of TSWV replication, as measured by NSs accumulation, were similar in both TT and WFT.


2009 ◽  
Vol 62 ◽  
pp. 408-408
Author(s):  
R.A. Lister ◽  
J.D. Fletcher ◽  
G.M. Timmerman-Vaughan

The capsid protein genes of thirteen isolates of tomato spotted wilt virus (TSWV) (Tospovirus) occurring in New Zealand have been sequenced TSWV is a thripsvectored virus causing serious damage in field and covered crops With recent new incursions of thrips species and tospoviruses it was considered of interest to identify what if any sequence variation occurs in the New Zealand TSWV isolates both from a temporal and geographic perspective The material chosen for sequencing was sourced from fresh glasshouse and field samples and also from samples that had been stored frozen for several years The oldest TSWV isolate was collected in 1992 and stored frozen since then and the most recently collected was from fresh material in 2008 Samples were obtained from several geographic locations throughout New Zealand When compared to the worldwide TSWV capsid gene sequence data held in GenBank cluster analysis of the sequence data has placed the New Zealand isolates into distinct groups Observations of the most closely related strains on a global scale may provide clues to the country of origin from which historic TSWV incursions into New Zealand originated


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.


1998 ◽  
Vol 88 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Marjolein Kikkert ◽  
Cor Meurs ◽  
Fennet van de Wetering ◽  
Simone Dorfmüller ◽  
Dick Peters ◽  
...  

Using protein blot assays, a 94-kDa thrips protein was identified that exhibited specific binding to tomato spotted wilt virus (TSWV) particles. Renaturation of the 94-kDa protein, which is conserved among the two major vector species of TSWV, Frankliniella occidentalis and Thrips tabaci, was crucial for its virus-binding properties, whereas under the same conditions no specific binding was observed with aphid (Myzus persicae) proteins. The 94-kDa protein species was present in all developmental stages of both vectoring thrips, whereas it was present mainly in the adult stage of a nonvectoring thrips species, Parthenothrips dracenae. Using antibodies against the different TSWV structural proteins, the G2 envelope glycoprotein was identified as the viral determinant involved. Because the virus-binding protein is present throughout the thrips body, but not in the gut, it may represent a receptor protein involved during circulation of the virus through its vector but probably not during viral uptake in the midgut.


2004 ◽  
Vol 94 (4) ◽  
pp. 333-336 ◽  
Author(s):  
F. M. de Assis Filho ◽  
C. M. Deom ◽  
J. L. Sherwood

Only larval thrips that acquire Tomato spotted wilt virus (TSWV), or adults derived from such larvae, transmit the virus. Nonviruliferous adults can ingest virus particles while feeding on TSWV-infected plants, but such adult thrips have not been shown to transmit TSWV. Immunofluorescence microscopy was used to show that thrips 1, 5, 10, and 20 days after adult emergence (DAE) fed on TSWV-infected plants acquired TSWV with virus replication and accumulation occurring in both epithelial and muscle cells of Frankliniella fusca (tobacco thrips [TT]) and F. occidentalis (western flower thrips [WFT]), as indicated by immunodetection of the nonstructural (NSs) protein encoded by the small RNA and the nucleocapsid (N) protein, respectively. Adult WFT acquired TSWV more efficiently than TT. There was no significant effect of insect age on TSWV acquisition by TT. In contrast, acquisition by adult WFT at 1 and 5 DAE was higher than acquisition at 10 and 20 DAE. Subsequent transmission competence of adult cohorts was studied by vector transmission assays. All adult thrips tested that had an acquisition access period as an adult were unable to transmit the virus. These results indicate the susceptibility of adult TT and WFT to infection of midgut cells by TSWV and subsequent virus replication and confirm earlier studies that adult thrips that feed on virus-infected plants do not transmit the virus. The role of a tissue barrier in TSWV movement and infection from midgut muscle cells to the salivary glands is discussed.


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