scholarly journals The Efficiency by Which Thrips tabaci Populations Transmit Tomato spotted wilt virus Depends on Their Host Preference and Reproductive Strategy

2002 ◽  
Vol 92 (6) ◽  
pp. 603-609 ◽  
Author(s):  
Elisavet K. Chatzivassiliou ◽  
Dick Peters ◽  
Nikolaos I. Katis

Arrhenotokous and thelytokous populations of Thrips tabaci from tobacco or leek plants were evaluated for their ability to transmit Tomato spotted wilt virus (TSWV) and for their host preference. Transmission efficiencies were comparatively studied using leaf disks of Petunia hybrida, Datura stramonium, and Nicotiana tabacum cv. Basmas. Adults of arrhenotokous populations collected on infected tobacco plants in the field were efficient transmitters (up to 48.5% transmission) and remained so when maintained on tobacco for several generations. Arrhenotokous T. tabacipopulations from leek plants were poor transmitters (up to 3.1% transmission), whereas no transmission was obtained with thelytokous populations from leek. All populations could infest leek, however none of the arrhenotokous and thelytokous populations from leek plants was able to infest tobacco. TSWV could be acquired by both first and second larval instars of a T. tabacipopulation from tobacco. However, the transmission by adults decreased with the age at which the virus was acquired by larvae. The highest efficiencies (61% of males and 51% of females transmitted) were obtained when newborn (0- to 24-h old) larvae acquired the virus. The majority of thrips started to transmit after becoming adult and rates were positively correlated with the temperature at which the thrips were kept. The median latent period values found for adults decreased with increasing temperature. The median acquisition access period (AAP50) of the population was 41 min, whereas the AAP50 was 65 min for males and 35 min for females. The median inoculation access period of males was 246 and 365 min on tobacco and petunia, respectively, and 96 and 345 min for females. The results show that T. tabaci forms a complex in terms of host preference, reproductive strategy, and ability to transmit TSWV. The transmission parameters show that the thrips of arrhenotokous populations infesting tobacco are highly efficient vectors.

1974 ◽  
Vol 52 (6) ◽  
pp. 1177-1182 ◽  
Author(s):  
Y. C. Paliwal

A virus isolated from white clover (Trifolium repens L.), dahlia, and tomato from Ontario, dahlia from Manitoba, and tomato and dahlia from British Columbia was identified as tomato spotted wilt virus (TSWV). Seven isolates of the virus examined had similar host reactions; four of them, investigated in detail, were similar in their localization in tomato leaf cells and physical properties also. The virus particles, 78–97 nm in diameter, were abundant in tomato leaf mesophyll cells and occurred in clusters or arrays surrounded by a membrane.The virus was purified by a method modified from a previously reported one and a specific antiserum was prepared. TSWV appears to be weakly immunogenic, as a high titer antiserum could not be obtained.At least three species of thrips, i.e. Thrips tabaci Lind., Frankliniella fusca Hinds, and F. occidentalis Perg., known as vectors of TSWV elsewhere, occur in Canada. F. fusca, which occurs in eastern Canada, efficiently transmitted all isolates of the virus. T. tabaci, a vector in several countries and widespread in Canada, failed to transmit the virus.


1997 ◽  
Vol 87 (11) ◽  
pp. 1168-1173 ◽  
Author(s):  
Alice K. Inoue-Nagata ◽  
Richard Kormelink ◽  
Tatsuya Nagata ◽  
Elliot W. Kitajima ◽  
Rob Goldbach ◽  
...  

The generation of defective interfering (DI) RNA molecules of tomato spotted wilt tospovirus (TSWV) was studied by serially passaging in-ocula from plant to plant under different controlled conditions. DI RNAs were generated at higher rates in plants at 16°C than in plants incubated at higher temperatures. Another factor promoting the TSWV DI RNA generation was the use of high virus concentrations in the inocula. The solanaceous species Capsicum annuum, Datura stramonium, Lycopersicon esculentum, Nicotiana benthamiana, and N. rustica supported the generation of DI RNAs, whereas the virus recovered from the inoculated composite species, Emilia sonchifolia, remained free of any DI RNA under all conditions tested. This study resulted in a strategy to maintain DI RNA-free TSWV isolates, as well as in an efficient way to produce a large population of different DI RNA species. A single DI RNA species usually became dominant in an isolate after a few rounds of serial inoculations. The possible mechanisms involved in TSWV DI RNA generation under different inoculation circumstances are discussed.


Plant Disease ◽  
2001 ◽  
Vol 85 (12) ◽  
pp. 1290-1290 ◽  
Author(s):  
A. R. Golnaraghi ◽  
N. Shahraeen ◽  
R. Pourrahim ◽  
Sh. Ghorbani ◽  
Sh. Farzadfar

During the summers of 1999 and 2000, 3,110 soybean (Glycine max) leaf samples were randomly collected from soybean fields in the Ardebil, Goletan, Khuzestan, Lorestan, and Mazandaran provinces of Iran. Tomato spotted wilt virus (TSWV) was detected in leaf samples by TSWV-specific polyclonal antibody (As-0526 and As-0580, DSMZ, Braunschweig, Germany) in double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Mechanical inoculation of 26 plant species (10 plants per species) and cultivars with extracts of positive leaf samples produced necrotic local lesions in Beta vulgaris, Chenopodium quinoa, C. amaranticolor, Gomphrena globosa, Phaseolus vulgaris cv. Talash, Vicia faba, and Vigna unguiculata cv. Mashad; produced systemic chlorosis followed by necrosis in Datura stramonium, D. metel, Nicotiana rustica, N. tabacum cv. Samsun, N. glutinosa, N. bentamiana, and Glycine max cv. Hill; and produced chlorosis, stunting, and bud necrosis in Arachis hypogaea (peanut). Plants developing these symptoms following mechanical inoculation with extracts from original soybean leaves were positive in ELISA for TSWV. ELISA results indicate that the overall incidence of TSWV on soybean in the five provinces was 5.4%. TSWV has been reported in potato (2) and tomato (1) from Iran, but to our knowledge, this is the first report of the occurrence of TSWV on soybean in Iran. References: (1) K. Bananej et al. Iran. J. Plant Pathol. 34:30, 1998. (2) R. Pourrahim et al. Plant Dis. 85:442, 2001.


Author(s):  
Casey L. Ruark-Seward ◽  
Brian Bonville ◽  
George Kennedy ◽  
David A. Rasmussen

AbstractTomato spotted wilt virus (TSWV) is a generalist pathogen with one of the broadest known host ranges among RNA viruses. To understand how TSWV adapts to different hosts, we experimentally passaged viral populations between two alternate hosts, Emilia sochifolia and Datura stramonium, and an obligate vector in which it also replicates, western flower thrips (Frankliniella occidentalis). Deep sequencing viral populations at multiple time points allowed us to track the evolutionary dynamics of viral populations within and between hosts. High levels of viral genetic diversity were maintained in both plants and thrips between transmission events. Rapid fluctuations in the frequency of amino acid variants indicated strong host-specific selection pressures on proteins involved in viral movement (NSm) and replication (RdRp). While several genetic variants showed opposing fitness effects in different hosts, fitness effects were generally positively correlated between hosts indicating that positive rather than antagonistic pleiotropy is pervasive. These results suggest that high levels of genetic diversity together with the positive pleiotropic effects of mutations have allowed TSWV to rapidly adapt to new hosts and expand its host range.


2013 ◽  
Vol 2 (3) ◽  
pp. 121-136 ◽  
Author(s):  
Jae-Hyun Kim ◽  
Young-Soo Kim ◽  
Soo-Won Jang ◽  
Yong-Ho Jeon

We isolated tomato spotted wilt virus (TSWV-KP) from a diseased Capsicum annuum var. grossum with malformed leaves and necrotic spotted fruits. TSWV-KP produced necrosis or necrotic ring spots on inoculated leaves along with mosaic, vein necrosis, or death on the upper leaves on Datura stramonium, Nicotiana clevarandii, N. rustica, and N. tabacum cvs. Ultrastructurally, typical tospovirus particles were observed in the cytoplasm. The virion contained three molecules of genomic RNAs of approximately 9.0, 4.9, and 3.0 kb. The nucleocapsid (N) protein of the purified virion migrated as a single band with ~29 kDa molecular weight in SDS-PAGE. Complete nucleotide sequences of the large (L) genome segments of TSWV-KP were determined. Defective forms of L-RNA containing core polymerase regions were observed. L-RNA (8,917 nucleotides) contained a single open reading frame (ORF) in the viral complementary (vc) strand and encoded a 330-kDa protein. The L-protein had high identity in the “core-polymerase domain” with the corresponding regions of other tospoviruses. The complete nucleotide sequence of TSWV-KP medium-sized (M) RNA comprised 4,768 nucleotides and indicated a typical tospovirus with two genes in ambisense arrangement. The vRNA OFR coded for a potential cell-to-cell movement (NSm) 34.8-kDa protein; and the vcRNA ORF, for the viral glycoprotein (G1/G2) 128.0-kDa precursor. Multiple sequence alignment of the M-RNA showed highest homologies to TSWV-BR01. Amino acid sequences of TSWV-KP NSm and G1/G2 exhibited 48.7–85.3% and 34.9–96.2% identity, respectively. TSWV-KP small (S) RNA comprised 2,991 nucleotides with ambisense coding strategy. The sequence contained two ORFs—one in the viral sense, encoding a protein with predicted 52.4-kDa Mr; and another in the viral complementary sense, encoding the viral nucleocapsid protein of 28.8-kDa Mr. Amino acid sequences of TSWV-KP of S-RNA NSs and N exhibited 35.9–87.9% and 19.9–98.4% identity, respectively.


2002 ◽  
Vol 83 (3) ◽  
pp. 663-671 ◽  
Author(s):  
Tatsuya Nagata ◽  
Alice K. Inoue-Nagata ◽  
Jan van Lent ◽  
Rob Goldbach ◽  
Dick Peters

The competence of a Frankliniella occidentalis and a Thrips tabaci population to transmit Tomato spotted wilt virus (TSWV) was analysed. Adults of the F. occidentalis population transmitted this virus efficiently, whereas those of the thelytokous T. tabaci population failed to transmit. TSWV replicated in the midgut of the larvae of both populations after ingestion of virus; however, lower amounts accumulated in T. tabaci larvae than in F. occidentalis larvae. The virus was almost undetectable in T. tabaci adults, whereas high titres were readily detected in the F. occidentalis adults. The first infections in F. occidentalis larvae were detected by immunocytochemical studies in midgut epithelial and subsequently in midgut muscle cells, the ligaments, and finally in the salivary glands. The infections were weaker in the midgut epithelial and muscle cells of T. tabaci larvae, followed by an almost complete absence of any infection in the ligaments, and a complete absence in the salivary glands. Studies by electron microscopy revealed the budding of some virus particles from the basal membrane of midgut epithelial cells of F. occidentalis larvae into the extracellular space of the basal labyrinth. Enveloped virus particles were also seen in midgut muscle cells of F. occidentalis larvae. They were not discerned in epithelial and muscle cells of T. tabaci larvae and adults. This study showed that the rate of virus replication in the midgut and the extent of virus migration from the midgut to the visceral muscle cells and the salivary glands are probably crucial factors in the determination of vector competence.


Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 442-442 ◽  
Author(s):  
R. Pourrahim ◽  
Sh. Farzadfar ◽  
A. A. Moini ◽  
N. Shahraeen ◽  
A. Ahoonmanesh

Severe leaf and stem necrosis before flowering was observed in potato (Solanum tuberosum) fields of Firouzkoh Province, Iran, during the summer of 1998. Infected plants died before the end of the growing season. Necrosis was more severe in cv. Agria than in cvs. Ajaxs and Arinda. A high population of Thrips tabaci was observed in August and September. Tomato spotted wilt virus (TSWV) (1) was detected in affected potatoes by using specific TSWV-IgG (from Bioreba) in double-antibody sandwich enzyme linked immunosorbent assay and by indicator plant reactions. Mechanical inoculation of indicator plants with leaf extracts of symptomatic potatoes produce necrotic local lesions in Chenopodium quinoa, C. amaranticolor, Gomphrena globosa, Vicia faba, Vigna sinensis, Phaseolus aureus var. Gohar, P. vulgaris, and Petunia hybrida. The virus caused systemic necrosis in Capsicum frutescens, Datura stramonium, D. metel, Nicotiana glutinosa, N. rustica, and Trapaeolum majus, preceded by systemic chlorotic spots. TSWV was reported from ornamental crops in Tehran and Absard areas near to Firouzkoh province (2), but this is the first report of TSWV occurrence on potatoes in Iran. References: (1) T. S. Ie. Descriptions of Plant Viruses. No. 39, 1970. (2) A. A. Moeini, et al. Iran. J. Plant Pathol. (In press.)


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