First Report on the Multiplication of Tomato Spotted Wilt Tospovirus in Tobacco Thrips, Frankliniella fusca

Abstract

In Georgia, tomato spotted wilt tospovirus (TSWV) causes significant losses in peanut, tobacco, tomato, and pepper. Transmission of TSWV in Georgia primarily is by tobacco thrips (TT), Frankliniella fusca (Hinds), and western flower thrips, F. occidentalis (Pergande), with TT being the predominant vector species in peanut (2). TSWV must be acquired at the larval stage for the adult to transmit the virus. Detection of NSs (a non-structural TSWV protein present only following virus replication) in thrips by enzyme-linked immunosorbent assay (ELISA) is a reliable indicator that the virus had multiplied in the vector and thus the vector is competent to transmit TSWV. While this has been accomplished with F. occidentalis (1), information is lacking for F. fusca, the predominant vector in Georgia and other states in the Southeast. Thus, the nature of the TSWV-TT association was investigated and the proportion of transmitters in a field population determined in 1,436 individual adult TT collected from sticky cards positioned in selected peanut fields in south Georgia. Additionally, 650 larvae collected from volunteer peanut plants were reared to adults in the laboratory and the resulting 295 adult TT were individually evaluated by ELISA. Of those collected from the sticky cards, NSs was detected in 8% of the adult insects, indicating that the virus had multiplied in TT. NSs was not detected in control TT that had no access to the virus. Of the adult TT that emerged from larvae collected from volunteer peanuts, 6.1% were positive for NSs. Our study provides the first immunological evidence that TSWV multiplies in TT. References: (1) M. D. Bandla et al. Phytopathology 84:1427, 1994. (2) J. R. Chamberlin et al. J. Econ. Entomol. 86:40, 1993.

Analysis of Iris yellow spot virus replication in vector and non‐vector thrips species

“…Hence, conclusive evidence for tospovirus replication in thrips can only be obtained by the detection of non-structural proteins such as NSs or NSm that do not occur in the mature virus particles (Whitfield et al, 2005) and whose presence in the insect is therefore suggestive of replication of the viral genome in the vector (Kormelink et al, 1991;Kitajima et al, 1992). The NSs titres of Tomato spotted wilt virus (TSWV) were higher in vector thrips species such as F. occidentalis, F. fusca and F. bispinosa fed on TSWV-infected plants when compared to their counterparts fed on healthy plants (Bandla et al, 1994;Pappu et al, 1998;Avila et al, 2006). However, there is very little information on differences between vector and non-vector thrips species for TSWV NSs protein accumulation over time (de Assis Filho et al, 2005).…”

Evaluation of peanut genotypes for resistance to Tomato spotted wilt virus by mechanical and thrips inoculation

“…A previously described TSWV isolate (Pappu et al, 1998) was maintained on Emilia sonchifolia L., under greenhouse conditions, by thrips transmission using Frankliniella fusca (TT) and F. occidentalis Pergande (western flower thrips -WFT). Symptomatic plants were tested by enzyme-linked immunosorbent assay (ELISA) to confirm TSWV infection.…”

Midgut infection by tomato spotted wilt virus and vector incompetence of Frankliniella tritici

“…This was likely due to the repeated manipulation during species identification to assure the work was conducted with F. tritici , as F. occidentalis and F. bispinosa are morphologically very similar to F. tritici . TSWV previously identified ( Pappu et al., 1998), and used in our earlier work ( Assis Filho et al., 2002, 2004) was maintained on Emilia sonchifolia by thrips transmission and used for virus acquisition. First instar larvae, up to 24 h old, were given a 24 h acquisition access period (AAP) as previously described ( Assis Filho et al., 2002).…”