Sexual differences in transmission and accumulation of tomato spotted wilt virus in its insect vector Frankliniella occidentalis (Thysanoptera : Thripidae)

2006

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The effect of tomato spotted wilt virus (TSWV) infection on the life span of thelytokous Thrips tabaci, which is known as a TSWV vector with a low transmission rate, was studied in two populations, Shimane (SM) and Iwate (IW). No effects of virus infection were found in the developmental period and mortality of the thrips before adult emergence, but a significant increase was observed in age-specific mortality during the adult lifespan of the TSWVexposed thrips group when compared with the non-exposed group (mean total longevity of thrips exposed and not exposed to virus was 18.1 and 20.1 d in the SM population and 19.9 and 21.5 d in the IW population). The latent period (LP) was 14.2 d in the SM population and 17.2 d in the IW population, indicating a relatively longer LP than the LPs reported for Frankliniella occidentalis and F. fusca. The potential transmission period (PTP) from the end of the LP to vector death was only 3.3 d in both of the populations. The higher the level of virus infection, the greater the reduction in adult thrips survival. These results suggest that a long LP and TSWV-induced reduction of thrips survival shorten the PTP. This may be responsible for the low transmissibility of TSWV as well as the low transmission rate in thelytokous T. tabaci populations.

Section: Discussionsupporting

confidence: 55%

Infection of Tomato spotted wilt virus (TSWV) shortens the life span of thelytokous Thrips tabaci (Thysanoptera: Thripidae)

Inoue

2006

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“…In F. occidentalis, there exist differences in the ability of TSWV transmission among populations originating in various countries (van de Wetering et al, 1999a) and among different populations within Japan (Sakurai et al, 2002). In the same population, males have been found to transmit the virus more efficiently than females (Sakurai et al, 1998;van de Wetering et al, 1998van de Wetering et al, , 1999b. In T. tabaci, adults of arrhenotokous populations, which consist of both males and females, transmit TSWV at a higher rate than those of thelytokous populations, which consist of only females (Wijkamp et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

“…In order to detect TSWV particles in infected tomato plants and individual viruliferous thrips, TAS-ELISA was carried out as previously described (Sakurai et al, 1998) using commercially available polyclonal antibody (PAb, American Type Culture Collection, Manassas, VA, USA) for coating the wells, and monoclonal antibody (MAb, Agdia Inc., Elkhart, IN, USA) for detecting TSWV-N protein. The concentration of PAb was 1 mg/ml in a carbonate buffer (0.05 M sodium carbonate, pH 9.6), and that of MAb was 0.25 mg/ml in a phosphate-buffered saline (PBS, 0.14 M NaCl, 1 mM KH 2 PO 4 , 8 mM Na 2 HPO 4 , 2.5 mM KCl, pH 7.4), including 0.05% Tween 20, 2% polyvinylpyrrolidone (PVP-40) and 0.2% bovine serum albumin.…”

Section: Methodsmentioning

confidence: 99%

Transmission of Tomato spotted wilt virus by the dark form of Frankliniella schultzei (Thysanoptera: Thripidae) originating in tomato fields in Paraguay

2004

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The efficiency of Tomato spotted wilt virus (TSWV) transmission by the dark form of Frankliniella schultzei was studied in Paraguay using the petunia leaf disk assay. Twenty percent of F. schultzei females collected in a field with TSWV-infected tomato plants were found to be transmitters of the virus. When larvae, up to 8 h old, were given a virus acquisition access period of 24 h, many adults, 88.9% and 72.2% of all males and females, respectively, transmitted the virus. These results indicate that the dark form of F. schultzei originating in Paraguayan tomato fields can transmit TSWV efficiently and is an important vector of the virus.

“…However, it has been so far reported that there exists intraspecific variation in transmission competence of a tospovirus, Tomato spotted wilt virus (TSWV), by thrips vector species: the transmission efficiency of TSWV varied among populations in F. schultzei (Sakimura, 1969;Wijkamp et al, 1995), in F. occidentalis (van de Wetering et al, 1999a;Sakurai et al, 2002) and in T. tabaci (Wijkamp et al, 1995;Chatzivassiliou et al, 1999Chatzivassiliou et al, , 2002, and between sexes in F. occidentalis (Sakurai et al, 1998van de Wetering et al, 1998van de Wetering et al, , 1999b) and in T. tabaci (Chatzivassiliou et al, 1999). These findings suggest that the transmission efficiency of a newly occurring tospovirus in a specific area should be examined for thrips cultures originating from more than one population and for both sexes in all vector species of tospoviruses that live there.…”

Section: Introductionmentioning

confidence: 99%

“…Although five thrips species, F. occidentalis, F. intonsa, T. setosus, T. palmi and T. tabaci, have been confirmed as vectors of tospoviruses in Japan (Kobatake et al, 1976(Kobatake et al, , 1984Iwaki et al, 1984;Kato and Katayama, 1998;Sakurai et al, 1998;Inoue et al, 2002), the vector species of INSV have remained unknown. In the present study, adults of these five thrips species, after acquiring INSV at the first larval instar stage, were examined for their potential for virus accumulation and transmission to determine the primary vector species in Japan.…”

Section: Introductionmentioning

confidence: 99%

Distinct efficiencies of Impatiens necrotic spot virus transmission by five thrips vector species (Thysanoptera: Thripidae) of tospoviruses in Japan

Inoue

Tsuda

2004

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Five thrips species known as vectors of tospoviruses in Japan, Frankliniella occidentalis, F. intonsa, Thrips setosus, T. palmi and T. tabaci, were studied for their transmission competence of Impatiens necrotic spot virus (INSV). The competence was examined for adults that acquired the virus as newly hatched larvae using a petunia leaf disk assay. No members of the genus Thrips transmitted the virus; the INSV-N protein was not detected in them by DAS-ELISA. On the other hand, two species of the genus Frankliniella were confirmed as vectors of INSV. Both sexes of F. occidentalis transmitted the virus efficiently (males: 80.5%, females: 78.7%). In F. intonsa, however, the transmission efficiency was relatively low and differed between the sexes (males: 18.3%, females: 3.7%). Most F. occidentalis adults showing ELISA-positive values transmitted INSV; however, only one third of ELISA-positive F. intonsa adults did so. The amounts of the INSV-N protein in ELISA-positive and transmitting adults were larger in F. occidentalis than in F. intonsa by sex. These results show that the transmission of INSV may be characteristic of the genus Frankliniella, and that F. occidentalis is probably the primary vector of INSV in Japan.