A ProMED-mail post
http://www.promedmail.org
ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org

Date: Tue 15 Oct 2024
Source: Australian Broadcasting Corporation (ABC) [summ. Mod.DHA, edited]
https://www.abc.net.au/news/2024-10-15/tomato-brown-rugose-virus-quarantine-orders-overreach/104471616


Two tomato growers and one nursery have been placed into quarantine by the South Australian government due to the discovery of the tomato brown rugose virus (ProMED post 20240826.8718377). There are delays in testing samples from other tomato farms, because the only 2 national laboratories accredited for the virus are interstate. A total of 180 results are still pending, with a further 234 inconclusive samples to be retested.

This is the 1st time tomato brown rugose virus has been confirmed in Australia. The virus has been traced back to seeds imported in May 2024 that were sold to growers. The federal agriculture department said the seeds came with certifications that they had tested negative overseas for the virus. Last year [2023], the department tested about 40% of imported tomato seed lines. They say it would take significant resources to test more shipments at the border and that volume alone creates risk.

States and the Commonwealth have yet to agree on a formal process so growers can prove their property is free of the virus. It could be weeks before a clean-up protocol is finalised that both interstate counterparts and overseas trading partners are confident with. Some farmers are considering taking legal action against authorities.

[Byline: Angelique Donnellan]

--
Communicated by:
ProMED

[_Tomato brown rugose fruit virus_ (ToBRFV) was identified as a new member of the genus _Tobamovirus_ (type member _Tobacco mosaic virus_, TMV) in Jordan and soon after in Israel (see links below). Since then, it has also been reported from various other regions worldwide (e.g. recently from India, see link below) and continues to spread. The virus was shown to affect also capsicum and has been detected in both plants and seeds of both crops. ToBRFV symptoms on tomato vary depending on host cultivar but may include chlorosis, mottling, mosaic, crinkling (rugosis) on leaves; necrotic spots on petioles and calyces; yellowish mottling, brown spots and rugosis on fruit to make them unmarketable. On capsicum, leaf symptoms are similar; fruits may be deformed with yellow mottling or green stripes. Almost 100% incidence was reported for some outbreaks in tomato, but not every fruit on an infected plant may show symptoms.

ToBRFV (like many tobamoviruses) is seed transmitted and can also be spread by mechanical means, contaminated equipment, as well as with plant or other materials. It is very stable and can remain infectious for months outside a host. Bumblebees, which are used widely as commercial pollinators in glasshouse tomato production, have been shown to be effective vectors of ToBRFV (see link below). Volunteer crop plants and solanaceous weed species are likely pathogen reservoirs. The Tm-22 resistance gene used in some tomato cultivars to protect from other tobamoviruses (such as _Tomato mosaic virus_) does not appear to be effective against ToBRFV. Disease management relies mainly on exclusion but may include phytosanitation (disinfecting tools, removing crop debris) and control of virus reservoirs. Use of certified clean seeds or crop transplants is crucial. Research on possible seed treatments to eliminate the virus is being carried out (see link below). Tomato seeds are traded widely and are known to pose a risk of spreading viruses and other pathogens internationally (e.g., ProMED post 20140122.2222560).

Coinfection of ToBRFV with _Pepino mosaic virus_ (genus _Potexvirus_) and _Tomato spotted wilt virus_ (TSWV; genus _Orthotospovirus_) have been found in tomato (ProMED posts 20191029.6751082, 20200507.7307615), as well as with TSWV in capsicum (see link below). Other coinfecting partners may be expected to exist, with _Peru tomato mosaic virus_ suspected (_Potyvirus_; ProMED post 20240124.8714440). It is thought that respective symptoms in coinfections may be due to either virus or synergism. Further research is needed to clarify a potential role of ToBRFV in coinfections and to determine whether its presence in coinfections may have led to earlier cases of misdiagnosis and delayed identification of this new virus.

The virus had previously been suspected to be present in Australian tomato seed, but this was considered an unreliable record (see link below). Movements of host material (including seed, fruits, plants) between Australian states and to New Zealand have been stopped and biosecurity measures have been implemented in the entire region.

Pictures
ToBRFV on tomato:
https://gd.eppo.int/media/data/taxon/T/TOBRFV/pics/1024x0/4137.jpg and
https://gd.eppo.int/media/data/taxon/T/TOBRFV/pics/1024x0/4138.jpg
ToBRFV symptoms on capsicum:
https://agriculture.vic.gov.au/__data/assets/image/0009/555759/TOBRFV_figure-5.jpg

Links
Additional news story:
https://www.freshplaza.com/oceania/article/9668590/australian-workers-counting-cost-of-tobrfv/
Information and characterisation of ToBRFV:
https://gd.eppo.int/taxon/TOBRFV (with distribution and host list),
https://doi.org/10.1007/s00705-015-2677-7,
https://doi.org/10.1007/s42161-023-01436-8 (TSWV co-infection, capsicum) and via
https://www.semanticscholar.org/topic/Tomato-brown-rugose-fruit-virus/3579397
ToBRFV suspected in Australian seed:
https://gd.eppo.int/reporting/article-7016 (unreliable record)
ToBRFV spread:
https://doi.org/10.1094/PDIS-11-23-2413-PDN (new reservoir hosts),
https://doi.org/10.1371/journal.pone.0282441 (new reservoir hosts) and
https://doi.org/10.1371/journal.pone.0210871 (by pollinators)
Tomato resistance breeding:
https://www.hortidaily.com/article/9544570/intermediate-resistance-ir-to-tobrfv-in-tomato-varieties-confirmed/
ToBRFV seed treatment:
https://doi.org/10.1007/s10658-020-02151-1
International spread of tobamoviruses by seeds (review):
https://doi.org/10.5772/intechopen.70244
Virus taxonomy via:
https://ictv.global/taxonomy
- Mod.DHA

ProMED map:
South Australia, Australia: https://promedmail.org/promed-post?place=8719409,286]

See Also

Tomato brown rugose fruit virus - Australia: (SA) 20240826.8718377
Tomato brown rugose fruit virus - Ireland: 1st rep 20240522.8716653
Tomato brown rugose fruit virus - Peru: 1st rep 20240124.8714440
2023
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Tomato brown rugose fruit virus - Morocco: 1st rep 20231120.8713238
Tomato brown rugose fruit virus - Argentina: alert 20230711.8711078
Tomato brown rugose fruit virus - Canada: (ON) 20230315.8708961
2022
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Tomato brown rugose fruit virus & bacterial disease, vegetable crops - Spain: (AN) 20221114.8706732
Tomato mottle mosaic virus - Netherlands: 1st rep 20220912.8705545
Tomato brown rugose fruit virus - UK: reoccurrence 20220610.8703789
Tomato brown rugose fruit virus, capsicum - Russia ex China: intercept 20220511.8703187
2021
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Tomato brown rugose fruit virus - Syria: 1st rep 20210915.8669375
Tomato brown rugose fruit virus - Austria, Switzerland: 1st reps 20210811.8585572
Multiple viruses, tomato - India: (MH) 20210705.8495612
Tomato brown rugose fruit virus - Turkey: (AL) 20210524.8377530
Tomato brown rugose fruit virus - Italy: (SC) spread 20210309.8235916
Tomato brown rugose fruit virus - New Zealand: 1st rep 20210113.8100865
2020
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Tomato brown rugose fruit virus - Italy: (SC) 20201112.7936491
Tomato brown rugose fruit virus - Africa: 1st rep (Egypt) 20200507.7307615
Tomato brown rugose fruit virus - Spain: 1st rep (AN) 20200206.6959141
and additional items in the archives

Website: http://www.isid.org

Published: October 17, 2024