Viroid-infected Tomato and Capsicum Seed Shipments to Australia

Constable, Fiona; Chambers, Grant; Penrose, Lindsay; Daly, A.; Mackie, J T; Davis, Kevin; Rodoni, Brendan; Gibbs, Mark J.

doi:10.3390/v11020098

Cited by 29 publications

(28 citation statements)

References 37 publications

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“…with a sample of 400 seeds) are not likely to lead to a relevant reduction in the level of infected imported maize seed, given the low prevalence of Stewart's wilt at the origin, unless there is high variability in the infection level among consignments. This result is consistent with a study of viroid-infected tomato and capsicum seed shipments to Australia (Constable et al, 2019), which showed that when infected lots are largely composed of uninfected seeds and only a few infected seeds (i.e. something like one infected seed in 16,000 healthy seeds), then the number of seeds per lot that need to be sampled in order to have a realistic chance of detecting a pathogen is much higher than 400.…”

Section: Discussionsupporting

confidence: 90%

Risk assessment of the entry of Pantoea stewartii subsp. stewartii on maize seed imported by the EU from the USA

Bragard¹,

Dehnen‐Schmutz²,

Serio³

et al. 2019

EFS2

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Following a request from the European Commission, the EFSA Panel on Plant Health performed a risk assessment of the entry of Pantoea stewartii subsp. stewartii on maize seed imported by the EU from the USA. This pest is a Gram-negative bacterium which causes Stewart's vascular wilt and leaf blight of maize (including sweet corn), a disease responsible for serious crop losses throughout the world. The following scenarios were considered: scenario A0 (current practice), scenario A1 (US request for modification of EU conditions for derogation), and scenario A2 (EU conditions for derogation). Results from the quantitative seed pathway model presented here show that, despite the low rates of plant-to-seed and seed-toseedling transmission that have been reported in the literature for Stewart's wilt, given the amount of traded seed, and in the case of voluntary (i.e. not mandatory) inspections of seed production fields at the origin (i.e. scenario A0), the frequency of introducing the disease is in the order of magnitude of some hundred introductions per year (median number). The EU conditions for derogation would lead to a decrease in the likelihood of entry compared to scenarios A0 (about 10,000 times fewer introductions) and A1 (about 2,000 times fewer introductions). This protective effect is mainly due to the requirement that only genotypes resistant to Stewart's wilt are traded, with the additional field inspection (two instead of one per season) providing additional reassurance. The Panel also concluded that seed lot inspections, as currently carried out (e.g. with a sample of 400 seeds) are not likely to lead to a relevant reduction in the level of infected imported maize seed, given the low prevalence of Stewart's wilt at the origin. If, however, there is aggregation in infection among consignments, inspection would work towards identifying the highly infected consignments. Recently, outbreaks of Stewart's wilt have occurred in Italy (Emilia Romagna, Friuli, Lombardy and Veneto). A review is provided of the available information to assess the possible role of seed imports in these outbreaks.

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Section: Discussionsupporting

confidence: 90%

Risk assessment of the entry of Pantoea stewartii subsp. stewartii on maize seed imported by the EU from the USA

Bragard¹,

Dehnen‐Schmutz²,

Serio³

et al. 2019

EFS2

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“…In the case of NBT and NBHP libraries, from tomato and pepper plants, respectively, grown in Ninh Binh, CLVd was dominant in NBT, while ChiVMV was dominant in NBHP, suggesting host-specific viral populations. We carefully supposed that the dominance of CLVd in NBT library might be associated with seed transmission of CLVd, as reported previously [ 9 ]. Some viruses, such as PVY from BLT, were associated with NGS reads, but not detected with PCR.…”

Section: Discussionmentioning

confidence: 99%

“…Virus infections on tomatoes and peppers have a negative impact on these crops, such as low quality and quantity of fruit production [ 4 , 5 , 6 , 7 , 8 ]. Among the viruses infecting solanaceous vegetables, cucumber mosaic virus (CMV) in the genus Cucumovirus might be the most important virus for plants in the family Solanceae [ 9 ]. Tomato spotted wilt virus (TSWV) in the genus Tospovirus is a recently emerging plant virus that causes serious viral diseases in a wide range of important plants, including pepper and tomato [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, tomato yellow leaf curl virus (TYLCV) in the genus Begomovirus causes severe damage on tomato cultures [ 11 ]. Moreover, several viroids, such as citrus exocortis viroid (CEVd), columnea latent viroid (CLVd), pepper chat fruit viroid (PCFVd), potato spindle tuber viroid (PSTVd), tomato chlorotic dwarf viroid (TCDVd) and tomato apical stunt viroid (TASVd) in the family Pospiviroid , infect pepper and tomato plants [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

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Identification of Viruses and Viroids Infecting Tomato and Pepper Plants in Vietnam by Metatranscriptomics

Choi

Cho

et al. 2020

IJMS

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Tomato (Lycopersicum esculentum L.) and pepper (Capsicum annuum L.) plants belonging to the family Solanaceae are cultivated worldwide. The rapid development of next-generation sequencing (NGS) technology facilitates the identification of viruses and viroids infecting plants. In this study, we carried out metatranscriptomics using RNA sequencing followed by bioinformatics analyses to identify viruses and viroids infecting tomato and pepper plants in Vietnam. We prepared a total of 16 libraries, including eight tomato and eight pepper libraries derived from different geographical regions in Vietnam. We identified a total of 602 virus-associated contigs, which were assigned to 18 different virus species belonging to nine different viral genera. We identified 13 different viruses and two viroids infecting tomato plants and 12 viruses and two viroids infecting pepper plants with viruses as dominantly observed pathogens. Our results showed that multiple infection of different viral pathogens was common in both plants. Moreover, geographical region and host plant were two major factors to determine viral populations. Taken together, our results provide the comprehensive overview of viral pathogens infecting two important plants in the family Solanaceae grown in Vietnam.

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“…The testing regime can also result in detection of Citrus exocortis viroid (CEVd), which does not require regulatory exclusion in seed in Australia. A recent compilation of test results [4] showed that significant numbers of pospiviroid-contaminated tomato and capsicum seed lots were identified in the period 2012–2016 among seed lots proposed for import, reported details of recorded incidences (numbers of detections), and estimated prevalences (rates of contamination) of PSTVd.…”

Section: Introductionmentioning

confidence: 99%

Prevalences of Pospiviroid Contamination in Large Seed Lots of Tomato and Capsicum, and Related Seed Testing Considerations

Dall

Penrose

Daly

et al. 2019

Viruses

Self Cite

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Analyses of pospiviroids in commercial seed lots of tomato and capsicum, determined by testing of 12,000 to 40,000 seeds per lot, have enabled the development of empirically-derived distribution curves for the observed prevalences of viroids in those commodities. Those distribution curves can be considered in conjunction with statistically-based estimates of detection that would be achieved using other sample sizes. Statistical calculations using binomial distributions show that sample sizes of 3000 and 9400 seeds allow detection of viroid prevalences as low as 0.1% and 0.032%, respectively, with 95% confidence. Applying those calculations to observed viroid prevalences in contaminated tomato seed lots, it is estimated that the use of sample sizes of 3000 and 9400 seeds would detect 15% and 42%, respectively, of the contaminated seed lots identified using the larger sample sizes of approximately 20,000 seeds reported in this study. It is concluded that the higher costs associated with testing of larger sample sizes represent a worthwhile investment in agricultural biosecurity.

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Viroid-infected Tomato and Capsicum Seed Shipments to Australia

Cited by 29 publications

References 37 publications

Risk assessment of the entry of Pantoea stewartii subsp. stewartii on maize seed imported by the EU from the USA

Risk assessment of the entry of Pantoea stewartii subsp. stewartii on maize seed imported by the EU from the USA

Identification of Viruses and Viroids Infecting Tomato and Pepper Plants in Vietnam by Metatranscriptomics

Prevalences of Pospiviroid Contamination in Large Seed Lots of Tomato and Capsicum, and Related Seed Testing Considerations

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