Detailed Timeline: Management of Tomato Spotted Wilt Virus (TSWV)
Early 20th Century (pre-1915)
Prior to 1915: Tomato Spotted Wilt Virus (TSWV) exists as a plant pathogen.
1915
1915: The “spotted wilt” disease of tomato is first reported in Australia.
1930s
1930: TSWV is formally described, and the genus Tospovirus is named after it. TSWV remains the only recognized Tospovirus until genetic screening expands the known species in the 1990s.
1980s
Since the 1980s: Extensive efforts are undertaken in the southeastern states of the USA to develop and improve integrated pest management strategies for TSWV in peanuts, incorporating chemical and cultural practices for thrips control, and the use of resistant plant species.
1985
1985: Sanford and Johnston propose the “parasite-derived resistance” concept, suggesting that resistance genes can be derived from the parasite’s own genome.
1991
1991: Gielen et al. inadvertently achieve TSWV resistance in transgenic tobacco plants by expressing TSWV’s nucleocapsid (N) protein, initially believing the resistance was due to the protein itself.
1992
1992: De Haan et al. confirm that the resistance observed by Gielen et al. in transgenic tobacco plants is mediated by RNA homologous to the N gene sequence, not the N protein.
1992: Sanders et al. report field resistance of transgenic tomatoes expressing Tobacco Mosaic Virus or Tomato Mosaic Virus coat protein genes.
1996
1996: Prins et al. demonstrate that engineered RNA-mediated resistance to TSWV is sequence-specific.
1996: Wijkamp et al. study the median acquisition and inoculation access periods for Frankliniella occidentalis (western flower thrips) in transmitting TSWV, finding periods as short as 5 minutes for transmission.
1996: Van de Wetering et al. discover that TSWV ingestion by first instar larvae of Frankliniella occidentalis is a prerequisite for transmission.
1997
1997: Ratcliff et al. find a similarity between viral defense and gene silencing in plants.
1998
1998: Waterhouse et al. show that virus resistance and gene silencing in plants can be induced by simultaneous expression of sense and antisense RNA.
1999
1999: Qiu and Moyer report that TSWV can adapt to N gene-derived resistance in plants through genome reassortment.
1999: Nagata et al. investigate tissue tropism related to vector competence of Frankliniella occidentalis for TSWV.
2000
2000: Jan et al. determine that a minimum length of N gene sequence in transgenic plants is required for RNA-mediated tospovirus resistance.
2000: Nelson et al. publish on the cellular biology of proton-motive force generation by V-ATPases.
2000: Riley and Pappu evaluate tactics for managing thrips-vectored TSWV in tomato.
2001
2001: Tenllado and DÃaz-RuÃz report double-stranded RNA-mediated interference with plant virus infection.
2001: Dzitoyeva et al. demonstrate that intra-abdominal injection of dsRNA in Drosophila triggers RNAi in the central nervous system.
2002
2002: Takeda et al. identify the NSs protein of TSWV as a novel RNA silencing suppressor.
2003
2003: Tenllado et al. show that crude extracts of bacterially expressed dsRNA can be used to protect plants against virus infections.
2003: Maris et al. investigate the restricted spread of TSWV in thrips-resistant pepper.
2004
2004: Sonoda and Tsumuki analyze RNA-mediated virus resistance by NSs and NSm gene sequences from TSWV, finding NSm or N genes were most effective for resistance.
2004: Riley and Pappu detail tactics for managing thrips and TSWV in tomato.
2006
2006: Bucher et al. achieve multiple virus resistance at high frequency using a single transgene construct.
2006: Sen and Blau publish “A Brief History of RNAi: The Silence of the Genes.”
2006: Lycett et al. describe Anopheles gambiae P450 Reductase.
2006: Araujo et al. demonstrate RNA interference of salivary gland nitrophorin 2 in Rhodnius prolixus.
2007
2007: Baum et al. report the control of coleopteran insect pests through RNA interference.
2007: Molnár et al. suggest that specific regions of a viral genome, particularly secondary stem-loop structures, are the main progenitors of vsiRNA, rather than dsRNA replicative intermediates.
2007: Ding and Voinnet review antiviral immunity directed by small RNAs.
2007: Aalto et al. describe large-scale production of dsRNA and siRNA pools using bacteriophage Φ6 RNA-dependent RNA polymerase.
2007: Margaria et al. provide evidence that TSWV’s NSs protein is the avirulence determinant in interaction with Tsw gene-carrying resistant pepper.
2008
2008: Zhang et al. show that crude extracts of bacterially expressed dsRNA can protect tobacco plants against Cucumber Mosaic Virus infections.
2008: Bosco et al. study the colonization and predation of thrips by Orius species in sweet pepper greenhouses.
2008: Aliyari et al. investigate the mechanism of induction and suppression of antiviral immunity by virus-derived small RNAs in Drosophila.
2008: Tomoyasu et al. conduct a genome-wide survey for RNAi genes in Tribolium.
2009
2009: Hassani-Mehraban et al. find that RNAi-mediated transgenic tospovirus resistance can be overcome by intraspecies silencing suppressor protein complementation.
2009: Whyard et al. show that ingested double-stranded RNAs can act as species-specific insecticides.
2010
2010: Schnettler et al. discover diverging affinity of tospovirus NSs proteins for various RNA duplex molecules.
2010: Gan et al. demonstrate that bacterially expressed dsRNA protects maize against Sugarcane Mosaic Virus infection.
2010: Huvenne and Smagghe review mechanisms of dsRNA uptake in insects and potential of RNAi for pest control.
2011
2011: Mao et al. show that cotton plants expressing CYP6AE14 dsRNA have enhanced resistance to bollworms.
2011: Lin et al. achieve resistance to DNA and RNA viruses in transgenic plants using a single chimeric transgene construct.
2011: Riley et al. (University of Georgia) publish “Managing Tomato Spotted Wilt in Tomato in Georgia.”
2011: Terenius et al. provide an overview of RNA interference in Lepidoptera.
2011: Zhu et al. investigate ingested RNA interference for managing Colorado potato beetle populations.
2012
2012: Gao et al. review western flower thrips resistance to insecticides, mechanisms, and management strategies.
2013
2013: Mitter et al. analyze differential expression of TSWV-derived viral small RNAs in infected host plants.
2013: De Ronde et al. confirm that Tsw gene-based resistance is triggered by a functional RNA silencing suppressor protein of TSWV.
2013: Scott et al. discuss elements of successful insect RNAi.
2014
2014: Margaria et al. demonstrate that TSWV’s NSs protein is required for persistent infection and transmission by Frankliniella occidentalis.
2014: Peng et al. achieve broad-spectrum transgenic resistance against distinct tospovirus species at the genus level.
2014: Palli reviews RNA interference in Colorado potato beetle.
2014: Zhai et al. perform mutational analysis of two highly conserved motifs in the silencing suppressor encoded by TSWV.
2014: Lau et al. show that crude extracts of bacterially-expressed dsRNA protect orchid plants against Cymbidium Mosaic Virus.
2014: De Ronde et al. analyze TSWV NSs protein, indicating the importance of the N-terminal domain for avirulence and RNA silencing suppression.
2015
2015: Badillo-Vargas et al. introduce RNA interference tools for Frankliniella occidentalis.
2015: Ocampo et al. study antiviral RNA silencing suppression activity of TSWV NSs protein.
2015: Ammara et al. report RNAi-based resistance in transgenic tomato plants against Tomato Yellow Leaf Curl Virus.
2015: Hedil et al. analyze Tospovirus NSs proteins in suppression of systemic silencing.
2015: Csorba et al. review viral silencing suppressors.
2016
2016: Whitten et al. report symbiont-mediated RNA interference in insects.
2016: Ishii and Araki discuss consumer acceptance of food crops developed by genome editing.
2016: San Miguel and Scott demonstrate that dsRNA is stable as a foliar-applied insecticide.
2016: Mitter et al. evaluate candidate genes for artificial microRNA-mediated resistance to TSWV, finding the N gene as the best target.
2016: Batuman et al. report the first resistance-breaking strain of TSWV infecting tomatoes with the Sw-5 gene in California.
2016: Goic et al. show that virus-derived DNA drives mosquito vector tolerance to arboviral infection.
2017
2017: Kumar et al. report RNAi-derived transgenic resistance to Mungbean Yellow Mosaic India Virus in cowpea.
2017: Mitter et al. demonstrate the use of clay nanosheets for topical delivery of RNAi for sustained protection against plant viruses.
2017: Almási et al. discover that a single point mutation in TSWV NSs protein is sufficient to overcome Tsw-gene-mediated resistance in pepper.
2017: Zhao et al. investigate pesticide-mediated interspecific competition between local and invasive thrips pests.
2018
2018: Garcia-Ruiz et al. find that TSWV NSs protein supports infection and systemic movement of a potyvirus and is a symptom determinant.
2018: Leggewie and Schnettler review RNAi-mediated antiviral immunity in insects and its application.
2018: Poirier et al. show Dicer-2-dependent generation of viral DNA from defective genomes of RNA viruses modulates antiviral immunity in insects.
2018: Van Lenteren et al. discuss biological control using invertebrates and microorganisms.
2019
2019: Wu et al. show that the Orthotospovirus NSs protein suppresses plant MYC-regulated jasmonate signaling, leading to enhanced vector attraction.
2019: Worrall et al. demonstrate that exogenous application of RNAi-inducing dsRNA inhibits aphid-mediated transmission of a plant virus.
2019: Han et al. develop a bioassay system for dsRNA feeding to F. occidentalis and identify genes that induce mortality through dsRNA uptake.
2019: Olaya et al. identify and localize Tospovirus genus-wide conserved residues in 3D models.
2019: Cagliari et al. review management of pest insects and plant diseases by non-transformative RNAi.
2020
2020: Tabein et al. find that an effective dsRNA-mediated resistance against TSWV by exogenous application depends largely on the selection of the viral RNA target region.
2020: Andongma et al. optimize dietary RNAi delivery to Western Flower Thrips and Onion Thrips.
2020: Nilon et al. conduct studies targeting thrips using exogenous application of dsRNA to further manage TSWV.
2020: Wytinck et al. provide insights into dsRNA uptake in plant pests and pathogens for RNAi-based control.
2020: The University of Georgia’s Cooperative Extension updates “Managing Tomato Spotted Wilt in Tomato in Georgia.”
2020: Purdue University’s “Vegetable Crops Hotline” publishes “Tips for Managing Tomato Spotted Wilt Virus (TSWV)” by Elizabeth Long and Laura Ingwell.
2021
March 9, 2021: The article “Current Status and Potential of RNA Interference for the Management of Tomato Spotted Wilt Virus and Thrips Vectors” by Nilon, Robinson, Pappu, and Mitter is published.
Throughout 2021: Seed catalogs (e.g., Cornell Vegetables) list varieties with resistance to various diseases, including TSWV.
2022
June 2022: Two different resistance-breaking variants of TSWV are detected on separate, but nearby, tomato farms in North Carolina on tomato cultivars with the Sw-5 resistance gene.
Subsequent years (post-2022): These resistance-breaking variants of TSWV are detected on tomato, suggesting their persistence in the environment.
2023
Throughout 2023: Seed catalogs continue to list varieties with resistance to TSWV (e.g., Cornell Vegetables).
August 23, 2023: Elizabeth Long and Laura Ingwell publish “Tips for Managing Tomato Spotted Wilt Virus (TSWV)” in Purdue University’s Vegetable Crops Hotline.
Ongoing (as of 2023): Texas A&M AgriLife Research and Extension Center at Amarillo continues to research thrips-transmitted TSWV, noting the increasing incidence of resistance-breaking strains globally.
2024
July 1, 2024: NC State Extension Publications publish “Tomato Spotted Wilt Virus on Tomato and Pepper” by Andy Cooper and Inga Meadows, noting the detection of resistance-breaking variants in NC in 2022.
August 19, 2024: Shahmohammadi et al. publish that TSWV suppresses the antiviral response of Frankliniella occidentalis by elevating an immunosuppressive C18 Oxylipin level using its virulent factor, NSs.
2025
January 14, 2025: Trust Seeds publishes “TSWV Major agricultural challenge,” highlighting the economic impact of the virus.
February 11, 2025: Kim et al. publish “Effective Tomato Spotted Wilt Virus Resistance Assessment Using Non-Destructive Imaging and Machine Learning.”
June 18, 2025: Farmonaut® publishes “Best Insecticide for Thrips | Tomato Thrips Control Tips.”
