Open Source Plant Breeding Forum

Has anyone else heard of this new threat to tomatoes? I had not until I got my 2020 catalogue from Seeds from Italy. Their blog says this about it.

QuoteA bit of background on the problem: The disease called Tomato Brown Rugose Fruit Virus (ToBRFV) was first found in tomatoes in Jordan in 2015. It has since been found in California, Mexico, Germany, Italy, Spain, Netherlands, United Kingdom, China, Saudi Arabia, and Greece. The virus is harmless to humans and animals. It affects only tomatoes and peppers, and it causes fruits to get brown wrinkled spots that make the crop unmarketable. ToBRFV is very contagious and can be transmitted on workers' hands, clothing, tools, and so on. There are no resistant varieties.

You can read the whole thing here https://www.growitalian.com/blog/import-restrictions-on-tomato-pepper-seed/
(https://www.growitalian.com/blog/import-restrictions-on-tomato-pepper-seed/)

https://patents.google.com/patent/EP3409106A1/en

Was wondering about resistance. Only found the words "no commercial variety" in regards to resistance and this creepy Google patent.

It is a Tobamovirus, which is generally a pretty nasty group of viruses.  The most famous one is Tobacco Mosaic Virus.  They spread easily by contact.  These are among the most stable viruses and can survive on surfaces and in debris for years at moderate temperatures.  Decontamination is challenging.  The viruses also often infect the seed coat, sometimes penetrating sufficiently to prevent easy sterilization.  Even seeds treated with bleach or TSP can sometimes transmit the virus at a low rate.  Dry baking seeds at 170 degrees F for 72 hours is often sufficient though.

Here is some general info about controlling Tobamoviruses:
https://www.intechopen.com/online-first/aspects-in-tobamovirus-management-in-intensive-agriculture

It sounds like we should be cautious before importing seeds or fruit from impacted areas.

I would really like to know where we can find resistance genes for sure. Some of us have so much tomato diversity in our gardens we are liable to have some already, but its hard to know, there is far more germplasm than we can ever work with individually. I worked with nine species or hybrids thereof last year and got seed back for eight. There are at least four more species and lots of accessions out there. Somewhere in that incredible diversity there hopefully is good resistance.

Those of us in the US will hopefully have a while before we get hit. Sounds like it might be pretty widespread already in Europe and Asia.

The tm-1 gene from S. habrochaites provides resistance to several Tobamoviruses, but I couldn't find any information about ToBRFV, probably because it is new and little studied.

Never mind:

QuoteThe genus Tobamovirus currently includes 37 species, one  of  which  includes  the  type  member  research  model  tobacco  mosaic  virus  (TMV)  [10].  Most  tobamoviruses  are considered to be severe pathogens, e.g., tomato mosaic virus (ToMV) and tomato mottle mosaic virus (ToMMV) with worldwide distribution (Mexico, United States, China, Brazil, Jordan and Iran) [11–18], pepper mild mottle virus (PMMoV) in plants belonging to the family Solanaceae, and cucumber green mottle mosaic virus (CGMMV), which is found mostly in plants belonging to the family Cucurbita-ceae (cucurbits). Tobamoviruses are known to cause up to 30%, 20%, and 15% yield losses in pepper, tobacco, and cucumber, respectively [10, 19–21]. Since the 1960s, tomato yield  losses  attributed  to  tobamoviruses  have  decreased  dramatically due to the discovery and deployment of three genes: Tm-1, Tm-2, and Tm-22, which control resistance to TMV and ToMV infection [20, 22].

The single-stranded (ss) RNA genome of tobamoviruses encodes the small and large subunits of the viral replicase (Rep), which includes RNA-dependent RNA polymerase (RdRP) and helicase domains, as well as a coat protein (CP) and a movement protein (MP) [23]. The Tm-1 gene sup-presses infection via interactions with the helicase domain of the viral Rep [24, 25], whereas Tm-2 control is effected via an interaction with the viral MP [26]. Studies of mutations causing resistance breaking in viruses have demonstrated that this phenotype is mediated by a few mutations in a sin-gle viral gene (CP, MP, or Rep) [27, 28]. This applies to ToMV strains that can circumvent the resistance controlled by the Tm-2 and Tm-22 alleles via two point mutations in their MP [26, 29, 30]. In contrast, genomic sequencing of emerging resistance breakers has demonstrated that they can differ by 9–15% from known viruses (e.g., comparing ToMMV to TMV and ToMV). These differences may result from the innate mutability of the tobamovirus RNA genome [3].  Thus,  the  identification  of  possibly  rare  resistance-breaking mutations is hindered by a significant background of changes in their genomic sequences.

Recently,  a  new  tobamovirus  that  can  break  the  Tm-2/Tm-22 (and Tm-1) resistance of tomato was detected in Israel [31]. Genome sequence analysis and comparison to other sequences in the GenBank database showed this virus to be an Israeli isolate of tomato brown rugose fruit virus (ToBRFV-IL) with 99% genomic sequence identity (99% coverage) to a new tobamovirus ToBRFV that was reported in 2016 in Jordan [16]. Considering that previous studies have demonstrated that a few nonsynonymous substitution mutations can result in resistance breaking [26, 29, 30], we hypothesized that the resistance phenotype of this new virus is primarily a result of a few mutations. To facilitate identification  of  these  mutation  "needles"  in  a  genomic  "haystack", and to understand the evolutionary path lead-ing to the emergence of this new resistance-breaking virus, we performed a comprehensive genomic comparison and phylogenetic analysis of different tobamoviruses. Empow-ered by the large number of sequences from members of different species, the relationships between their hosts, and the number of variants per species used in this study, these approaches were found to be suitable for identifying resist-ance-breaking mutations. Our phylogenetic analysis local-ized all three ToBRFV genes between ToMV and RheMV/TMV host-shifting clades, and this, together with a relatively low mutation rate, suggests that a host shift contributed to the emergence of this new virus. Our comparative genomic analysis identified 12 potential resistance-breaking muta-tions in the MP gene, the primary target of Tm-2 resistance, and nine more in the Rep. Finally, molecular modeling of the helicase further confirmed the potential functional role of one of these mutations and enabled the identification of three more potential resistance-breaking mutations.

https://link.springer.com/article/10.1007/s00705-018-3819-5

What a wise and smart move is the promiscous tomato project initiated by Joseph ...

Quote from: Nicollas on 2020-02-11, 12:20:40 AM
What a wise and smart move is the promiscous tomato project initiated from Joseph ...

True that!

It is interesting how one project to increase genetic diversity for one form of biotic / abiotic factors will automatically increase it for others. I have high faith that the wild tomato genomes have what we need.

But I think Joseph is on to something specific: it might be better to create domestic-like tomatoes from the wild species rather than trying to create domestic tomatoes with wild genes using introgression lines, etc.

The wild genomes have what is termed "genetic drag", but it is sometimes this "genetic drag" exactly what we need/want. Maybe not all of it, but as much as possible without tasting odd, poisonous, or have other negative traits. Whenever possible I think it is best to preserve these wild genomes as intact as possible while introducing cultivated domestic genes like large tasty fruit.

It may require adjusting some expectations about what a tomato is or should be. Maybe we shouldn't be breeding for "tomatoes", maybe we should be breeding for Tomatoes 2.0 or the "post-tomato".

Quote from: Nicollas on 2020-02-11, 12:20:40 AM
What a wise and smart move is the promiscous tomato project initiated from Joseph ...

The possibility of resistance in the promiscuous population is greater but not guaranteed and more work may be required occasionally to introduce a needed resistance.

As Andrew says the wild tomato genomes probably have what we need, but have we yet incorporated the right populations into the promiscous project? Maybe not, we are by the necessity of a garden to small farm scale working with a small subset of available wild populations in the form of wild tomato accessions. It would help in a case like this if we had some publication that identified a few promising accessions from a researcher with some funding. 

https://link.springer.com/article/10.1007/s41348-021-00535-x?fbclid=IwAR3hD1ln84sVLhKA8lY4nNhjb_yeMkRJg9xKdxQXT99ppRrBHkKTxHXkDqE

https://link.springer.com/content/pdf/10.1007/s41348-021-00535-x.pdf

New article about (ToBRFV) The Brown Rugose Fruit Virus listing some resistance that has been found from 636 wild species accessions found about 31 resistant accessions or about 5 per 100 accessions.

In Solanum pimpinillifolium a long list of accessions they said 26 but I counted 19.

In Solanum habrochaites two accessions.

In Solanum chilense accession LA1932 which is already a notable accession for its ability to be crossed with domestic tomato. It is also an accession which I personally have not been able to get to set seed yet. Perhaps I should try growing it entirely indoors and in the greenhouse. 

In Solanum ochranthum which is very difficult to utilize except perhaps by somatic hybridization. Though this was the most interesting resistance they found because the plant in two cases seemed to have the ability to recover from the virus.

It seems that all domestic plants are susceptible?! Which doesn't bode well should the virus spread. Though given the many thousands of domestic varieties and the introgression of lots of wild genes into modern tomatoes, it would seem at least possible that somewhere there is a domestic or at least commonly cultivated currant type tomato that could be resistant. Still finding zero is a poor number at best. Also, resistance genes it seems like are concentrated near the center of tomato diversity with all Solanum pimpinillifolium's showing resistance coming from South America.

I went a little round looking for updates about this virus and the wikipedia article led me to this company which already is breeding for resistance.

https://www.enzazaden.com/news-and-events/news/2021/update-on-hr-tobrfv-tomato

Still doesn't bode well for heirloom tomatoes should the virus become widespread and common place. A similar effort to what Carol Deppe proposed for Late Blight could be necessary. Take either resistant strains of say Solanum pimpinillifolium or maybe resistant hybrids such as those being produced by the company above and cross those with heirlooms to spread the resistance into heirloom type fruits.

Another thing to worry about!  ...  Oh Joy!!

There was a British breeder whose mission statement included these words:

''Breeding objectives were focused on the amateur market, where there is a real need for modern, high quality open pollinated varieties.''

All six of their varieties are listed as ''ToBRFV free'', which, to my mind suggests that seed transmission is a problem!

https://www.gourmetgenetics.com/tomato/tomatoes.html

Tim DH

Yeah, I am not sure even how concerned to be. Is this a disease that will rapidly be in all of our gardens or is it a disease that may never spread to most of us?

Sounds like it is transmitted via seed.

Here is a link where we can track its spread:

https://gd.eppo.int/taxon/TOBRFV/distribution?fbclid=IwAR25vRzS57fJmFsUjlwOqBFD0IGxJYtLMJwSDmv5nyOa50MyUH8wxmW8Vu8

Attempting to breed for resistances would require us to have the virus to infect plants with.

Markers could help as well if we knew what genes were resistant.

I have heard of tobamovirus problems concerning tobacco and potatoes.

Fruit, leaves, seed - even touching leaves can trasmitt these viruses into a sterile room very easily.

Taking cuttings from very new growth might remove the virus, but it would probably return if it enters an area.

It may be eventually the case that the virus comes to us, but until then I am very happy it isn't here yet. I think it would be a good idea to wait for markers. Let university facilities deal with disease containment systems if needed. It looks like it maybe isn't spreading too fast and there will be resistant hybrids offered fairly soon. Then we can desegregate those hybrids to make our own open pollinated resistant tomatoes. Sort of crazy to think that we are often only one tomato pandemic away from not being able to grow tomatoes or what have you - basically insert the name of any crop in lieu of tomato.

https://m.youtube.com/watch?v=CnYUwb04xL0 Enza Zaden has genes for high resistance.

https://www.syngenta.co.uk/news/product-update/syngenta-introduce-first-commercial-tobrfv-resistant-tomato-variety

Syngenta has a variety out already.

Variety name is Lansor released in Israel so far.

Last winter I was able to request this toBRFV tolerant accession from the USDA ARS-GRIN

LA1375 PI 365967 Solanum pimpinellifolium

I've grown out some seed but not much because of poor pollination in the greenhouse. Plants are enormous though now.

I've managed to successfully cross it with my MMM line within my Mission Mountain project, so I have F1 seed for that to grow next year. I would like to share the F2 generation widely- ideally through EFN.

https://www.hortidaily.com/article/9484465/tobrfv-virus-a-pragmatic-approach/

I've been eyeballing the store tomatoes lately.

We import lots of tomatoes from Mexico.

Mexico has some TOBRFV infection.

Resistant varieties are being marketed there already but not here so far as I have read.

So I imagine some of the tomatoes in the stores might have resistance and also some of them might have infection with TOBRFV.

So most are perfect because consumers tend to reject anything but. However, I did spot one tomato with a big brown spot after looking a few different times.

I'm sure the inspectors are on heightened alert for tomato brown rugose virus and that keeping it out is a priority. I bet they do a great job.

However, resistance is often tolerance with infection still possible.

The virus is seed borne.

So if any infection sneaks through it will soon be in our compost piles etc.

I'm just curious here how long it will be before we all have this virus?

After looking online a bit I am pretty sure the tomato I spotted is just rotting or something. https://en.wikipedia.org/wiki/Tomato_brown_rugose_fruit_virus

It would be interesting to send a sample of seeds from the Beautifully Promiscuous and Tasty Tomato Project to a known-infected area and find out whether there are resistant genes in the line.

I think based on the study that found about 30 in 600 wild accessions that the odds of having a tolerant or resistant accession in the original project might not be great as that is one in twenty odds. So if we had 10 accessions in the original project we would have about half that chance that one of them contributed resistance. However, if we could include even 20 more distinct wild accessions the odds would go up. I think its a valid strategy to breed in lots of diversity to solve future problems I think its showing promise but I think chasing specific known sources of resistance is also a valid strategy that can take us to the same place quicker. Which is why I've crossed in an accession with known tolerance to this.

I went back to the store today. I think I may just be seeing infection. However this blotchy green uneven ripening looks more like some of the pathology photos. 

I noted it on three different tomato types all from Mexico. Same store could be the same supplier or different but still sort of intrigued. I wonder if there is a test for it. When I buy tomatoes I often throw the stem the core and anything that goes bad into the compost. Since this is seed transmitted I imagine that if there is any in the stores that it will spread.

 Thanks for the warning. I will stop composting my store-bought tomatoes for the foreseeable future.

Yeah that was one of my takeaways. Can no longer trust the military industrial complexes tomatoes in my compost!

Though actually finding out if the disease is there for sure does involve a test. My photos of blotchiness apparently aren't enough according to something I read. I'm sure big tomato growing states department of agriculture could run it for you if you saw a weird or suspicious one at a store.

I came to that same conclusion, no more store bought tomatoes in the compost and no more saving seed from them. Too bad because on the counter right now are some very dark purple ones from Mexico that are quite good for middle of winter store bought. If I hadn't happened on this thread, I very well may have planted some seeds.

I am sure that the government must be doing testing. If a small percentage of infection is getting through I would think they would know and be able to say how much by statistical analysis. Wonder if it is public knowledge and I would just have to find the right website. They must be doing a decent job because more infection reports aren't accumulating rapidly on the website that I did find that tracks them.

Also something to think about. Handling infected tomatoes and then touching your tomato plant without washing your hands could be enough to spread it. Apparently workers spread it in big greenhouses. So eat a infected cherry tomato for a snack from the store before tomato season. Then forget and touch your three week old tomato seedlings...


Missoula's urban compost is all composted and sold back to the public. Including human waste. I know tomato seeds survive the trip through humans largely because of stories on here but not sure if they survive the bioreactors at the sewage plant and then the year of composting. Back when I used to use it I never got a tomato sprout. I used it to propagate thousands of native plant seedlings as an intern some 20+ years ago. No unwanted seeds sprouted. Might be a phenomenon of smaller towns. Still I think composting tomatoes is fairly common.

I dumped some extra tomatoes, I think from Joseph's promiscuous tomatoes, in the home compost a few years ago and they sprouted mightily the next year.

If some of the store tomatoes are infected it is just possible that they are also tolerant and a source of resistance genes. When I looked it up they've released and are selling resistant strains already to growers in Mexico, Israel, and a few other countries. So oddly though we can't purchase resistant seed yet some of the fruit sold imported from Mexico could already be resistant.

I suppose someone saving seed from grocery store tomatoes would find out the hard way they had infected their garden when only their grocery store tomatoes looked good enough to eat. In that case. As a plant breeder you could still cross your old tomato strains with the new tolerant / resistant strains.

The practice of sending tomato seeds gardener to gardener internationally is I suspect pretty common based on the tomato seed swap groups. That carries the same or even higher risk especially as some countries have infection and the disease is spread by seed. I refuse those trades but could easily get second degree seed from someone who made such a trade themselves.

I also wonder how far the infection may have spread under the radar already. What if it was 2019 that we needed to not compost the fruit? Like is this really something the US government can keep stamped out for another ten years or at some point are we just going to find out that the infection is widespread and the catalogues all start offering resistant seed?

I did get one of the 33 tolerant strains of currant tomato mentioned in the article where they tested 600 wild accessions and I did make a cross with it in 2022. F1 seed is waiting to be grown out. Though Reed has written about how the spontaneous current crosses in his garden stay pretty small. So it must take big growouts to reclaim fruit size and resistance. We did get that back with Joseph's promiscuous project though.

If I found I was infected and the government didn't do anything heavy handed. I would save all the seed I could from grocery store tomatoes from Mexico and hope that some of it had additional resistance genes. Then do a lot of crossing to try to start building up tomato diversity with resistance.

Though if I was infected and aware of it I would also stop sharing tomato seed to anyone uninfected. Even resistant seed because it might be tolerance and still infected.

I'm also sure that if it does come here widely that the companies already growing resistant seeds will market them here as well. They may need to grow more seed though as the US is a pretty big tomato seed market. That would be the better source of resistance for breeding than random unidentified grocery store tomatoes as you could know for sure it was a resistant strain and potentially find out if it was ok to breed from legally.

That said if enough time passes all seeds are probably ok to breed from. So twenty to fifty years in the future at some point it would be ok to share theoretically. Though I wouldn't want to wait so I would want sources of tolerance / resistance I could freely breed from and share- like the currant tomato from GRIN.

It might in fact be ok to breed from grocery store tomatoes. Artisan seeds mentioned doing it on a post awhile back. They do serious tomato breeding. They also have a winter nursery in Mexico right now. I think they also licensed some material for late blight breeding.

I suspect that we shouldn't be too paranoid about this new disease. Though I would like some more info about infection rates in store bought tomatoes.

I read somewhere on the web that "resistant" commercial varieties currently available can still be infected, but are asymptomatic. So they could still pass the disease forward.

I also read that the US aggressively moved against ToBRFV in greenhouses, and claimed it had been eradicated from all US greenhouses.

Unfortunately I didn't make a note of where I read this, only that it appeared to be on some type of official site.

Of course, this is a moving target, and what is eradicated at one point can be infected the next.

Ultimately, I suspect we will have to obtain seed stock with true resistance (not just an asymptomatic carrier) and breed the resistance in any OP lines that we want to continue to grow, probably through repeated backcrossing.

Perhaps we'll get lucky and find resistant genes in the wild stock we are breeding for other purposes, perhaps not.

Jewehan, A., Salem, N., Tóth, Z. et al. Screening of Solanum (sections Lycopersicon and Juglandifolia) germplasm for reactions to the tomato brown rugose fruit virus (ToBRFV). J Plant Dis Prot 129, 117–123 (2022). https://doi.org/10.1007/s41348-021-00535-x

https://link.springer.com/article/10.1007/s41348-021-00535-x


The article on the 600 accessions found accessions that can clear the virus from their systems but in an extremely difficult to work with wild species Solanum ocranthum.

Some of the commercial breeders are claiming higher levels of resistance than others.

I am certain the accession I obtained is merely tolerant and therefore would be a carrier.

I suspect based on the 600-accession article that much of what is currently available as commercial varieties for infected areas is tolerant and may still be carriers.

However, in some ways I might be ok with just tolerance in this case.

Note: a quick search for Solanum ocranthum came up with no commercial seed sources. TGRC only lists 7 accessions. It is a woody tropical vine. Research articles talk about past attempts at introgression using somatic hybridization a cell fusion technique in plant tissue culture and TGRC has no introgression accessions like they've developed for other species. That makes me very dubious about obtaining, working with, or having success with the species short of someone going back to school for a doctoral degree trying to tackle this specific problem. It would be an intriguing problem for someone to solve.

I'm curious about how much of a real problem ToBRFV will be to amateur growers. Here in the UK the Government's web page on the issue says it will be updated on a monthly basis if there are any changes. ... and it hasn't been updated since Aug 2021!

https://planthealthportal.defra.gov.uk/latest-news/tomato-brown-rugose-fruit-virus-tobrfv-update-august-2021/

If you are worried about it, treating any 'foreign' (to you) seed with Sodium Hypochloride would be a sensible precaution.

https://virologyj.biomedcentral.com/articles/10.1186/s12985-020-01479-8

Tim DH

My impression is that it hasn't been a significant problem to amateur gardeners yet, but could easily become one.

I keep looking at the tomatoes in the local grocery store. Just emailed this photo from last week to the local county extension and asked about the possibility of ToBRFV testing.

Edit: MT does have the ability to test for it.

I think something that I don't know has been noted. Unsellable veg often goes to hog farmers. That manure goes on ground. Is it already being passed in the field.
And the unsellable veg also often goes to compost companies. Is this being killed off in compost conditions? Or is it already out there in compost likely.

It is seed borne so it probably survives fermentation and composting depending on how much heat for how long. Greenie has been getting volunteers from her tomato feeding.

I found out that the plant pathology lab in MT can test for it. So I plan to buy and send in a sample if I find suspicious tomatoes again.

This is a Dutch article about ToBRFV that I translated to English


Extra measures against deliberate infection with ToBRFV
 
 
 
The NVWA announces additional measures to combat the ToBRFV virus. These are particularly aimed at illegally infecting plants with a mild variant of the virus for so-called cross-protection.

The measures are necessary because inspections by the Dutch Food and Consumer Product Safety Authority (NVWA) show that several infected farms have a higher virus pressure. This greatly increases the risk of spreading to surrounding farms. The measures focus on farms with higher virus pressure and farms that illegally infect plants intentionally with tomato brown rugose fruit virus (ToBRFV).

This treatment with a mild variant provides cross-protection against more severe variants of the virus. The NVWA reports it will take enforcement action against companies that keep, propagate, trade the virus or intentionally infect plants with ToBRFV. The NVWA already warned growers last year not to apply cross-protection.

Cross-protection not allowed
ToBRFV spreads quickly, especially at high virus pressure, and can cause damage in the cultivation of tomatoes and peppers. The virus has a quarantine status in the European Union, and 48 infected tomato farms are now known in the Netherlands. Temporary emergency measures have been in place since November 2019 to prevent the spread of the virus.

The agent used in cross-protection contains a variant of ToBRFV. Application of an agent containing a quarantine organism is not allowed. The NVWA has indications that cross-protection is still being used. During inspections on several infected farms, inspectors found the ToBRFV variant from the illegal cross-protection agent.

Enforcement action
The drug is not authorized and therefore not assessed by the Ctgb. According to the NVWA, its use is not only prohibited, it also poses risks to users and surrounding businesses. The authority reports that enforcement action will be taken against suspected companies.

The cross-protection agent contains a mild variant of the virus, according to the manufacturer. This claim is not supported by scientific evidence, reports the NVWA. The drug, like other variants of the virus, causes damage to plants. Applying cross-protection increases the virus pressure within a farm site. It therefore becomes more difficult to eliminate the virus in a greenhouse.

New enforcement investigation
Last year, the NVWA completed a criminal investigation into the suspected producer of the cross-protectant and several companies that intentionally infected their plants. The file was turned in to the Office of the Public Prosecutor. The NVWA has indications that the producer of the drug has not stopped producing and selling it and has therefore launched a new enforcement investigation.

The penalties for illegal use and illegal trade in the banned drug depend on the facts and circumstances, the NVWA says. In addition to administrative measures, the companies that do use this method of cross-protection also risk criminal prosecution.

Translated with www.DeepL.com/Translator (free version)

Can we put at compost the fruits contaminated without infection if we remove the seeds of the fruit before to compost this or the peel and pulpit are also contaminated?
I think that the leafs and the rod and the roots are contaminated.

I would expect that the virus is in all the plants tissues and complete seed removal would be difficult. It is hard to avoid fresh tomatoes from commercial growers many of those imports this time of year in the Northern Hemisphere in entirety. My wife likes to buy cherry tomatoes in the winter, and I buy the occasional hamburger or taco with fresh tomato as a topping. I never used to think about not composting them. I used to compost every food scrap and have most of my life. Composting is becoming more common as some cities even mandate it as do more school lunch programs. Many organic farmers locally use urban compost collected separately from the waste streams that include biosolids as part of their compost inputs. This would almost inevitably include a small amount of tomato waste including seeds. Though I do wonder how effective hot compost might be at destroying the virus. There is also the risk of simply touching a infected commercial tomato and then touching a tomato plant which could easily spread this virus.

We bought two tomatoes from the grocery store and hope to have them tested. For free by the state lab.

That is interesting about the live virus cross protection with a mild strain and its illegality in that country. I could see the legality of the technique changing if it simply becomes impossible to keep the virus out. Innovative at least. Kind of like the technique of variolation which came before vaccination.

I have been curious about the potential for the resistant strains which are really merely tolerant to facilitate the virus's spread.

For instance, if these grocery store tomatoes have no resistance and this is the virus I am seeing, then a more resistant strain of tomato would mask the virus.

I think some of the resistant strains of tomato at least have some patent protection for the traits involved. That is potentially bad for independent breeders at least until the patents expire. It would also be a reason not to breed from random grocery store tomatoes as we will likely have useable sources of resistance and unusable sources. We will have to identify the usable.

If you had something like a mild resistance and you combined, it with the cross protection of the mild strain live virus you could likely mask the virus and produce lots of infected and saleable fruit. Though I wonder if the mild strain of virus allows non-resistant tomatoes to be grown in saleable condition. Very odd to think about!

I have grow the last year morrettino tomato with a tolerancy at TOMV.
https://www.ingegnoli.it/eng/pomodoro-hy-f1-morettino.html
Someone know this tomato?

Haven't heard of that F1 cultivar but tobacco mosaic virus while related as also a tobamavirus is a different virus than Tomato Brown Rugose Fruit Virus (ToBRFV) which we are discussing here. Similar spread in that you don't want to touch a source of tobacco mosaic virus and then touch many greenhouse grown seedlings like tomatoes, nicotianas, and petunias. Which I think will ultimately mean that ToBRFV will spread and we will need to cross in resistance- though tobacco mosaic virus has not caused the extinction of heirloom cultivars of tomato by any means.

From the article you linked in the original post :

QuoteTwenty-six accessions of S. pimpinellifolium (LA1301, LA1375, LA1547, LA1579, LA1607, LA1611, LA1612, LA1630, LA1634, LA1661, LA1670, LA1676, LA1679, LA1685, LA1728, LA1924, LA2903, LA2904, LA2982), two accessions of S. habrochaites (LA1559, LA2174), one accession of S. chilense (LA1932), and four accessions of S. lycopersicum var. cerasiforme (LA1456, LA2675, LA2688, LA1385) were found to be tolerant showing no symptoms at all or very mild mosaic symptoms with average disease severity between 0 and 20%.

Hello, this is a thread about breeding for tolerance and or resistance to the Tomato Brown Rugose Fruit Virus (ToBRFV)

Note: I am going to try to merge this new thread with our existing (New Tomato Disease Thread) on the same topic.

For some reason in the moderation tools I don't see an option to simply rename a whole topic. So I created a merge and then chose the new name for both threads. It looks to have worked.

Nice SEO title ;)

ToBRFV Infects the Reproductive Tissues of Tomato Plants but Is Not Transmitted to the Progenies by Pollination (https://www.mdpi.com/2073-4409/11/18/2864/htm)

QuoteTomato brown rugose fruit virus (ToBRFV), a newly identified Tobamovirus, has recently emerged as a significant pathogen of tomato plants (Solanum lycopersicum). The virus can evade or overcome the known tobamovirus resistance in tomatoes, i.e., Tm-1, Tm-2, and its allele Tm-22. ToBRFV was identified for the first time only a few years ago, and its interactions with the tomato host are still not clear. We investigated ToBRFV's presence in the reproductive tissues of tomato using fluorescent in situ hybridization (FISH) and RT-PCR. In infected plants, the virus was detected in the leaves, petals, ovary, stamen, style, stigma, and pollen grains but not inside the ovules. Fruits and seeds harvested from infected plants were contaminated with the virus. To test whether the virus is pollen transmitted, clean mother plants were hand pollinated with pollen from ToBRFV-infected plants and grown to fruit. None of the fruits and seeds harvested from the pollinated clean mother plants contained ToBRFV. Pollen germination assays revealed the germination arrest of ToBRFV-infected pollen. We concluded that ToBRFV might infect reproductive organs and pollen grains of tomato but that it is not pollen transmitted.

https://pubmed.ncbi.nlm.nih.gov/35262730/

A gene editing approach.

https://www.thepacker.com/news/industry/tobrfv-first-trial-results-confirm-high-resistance-level

This article about Enza Zaden's high resistance lines suggests that they have varieties that aren't just tolerant.

Though I suspect a plant could be tolerant and asymptomatic they show a nice figure that shows intermediate resistance as a lot like what I have been seeing mostly in the suspicious fruits in the grocery store. That sort of suggests that you might be able to pick out susceptible, and intermediate resistance just from visual observations. High resistance, tolerant but asymptomatic, and uninfected should all look the same.

The article that identified the 33 wild accessions with tolerance or resistance said that of the tolerant varieties' severity ranged from 0 to 20%. So tolerant but asymptomatic does exist. I wondered where the accession I obtained of Solanum pimpinillifolium was on that scale so I searched the article, and it didn't quantify that. It did confirm though that they recovered virus DNA from the accession so it is definitely a tolerant carrier.

William, all tested accessions are available in the supplementary document :
https://static-content.springer.com/esm/art%3A10.1007%2Fs41348-021-00535-x/MediaObjects/41348_2021_535_MOESM1_ESM.xlsx (https://static-content.springer.com/esm/art%3A10.1007%2Fs41348-021-00535-x/MediaObjects/41348_2021_535_MOESM1_ESM.xlsx)

Afaik the US brought in some strict regulations on importation of tomato seed almost two years ago in response to this particular virus.
Unfortunately I agree that imported fruit finding their way into home compost is the bigger threat.  I would expect some level of testing at the food import level to prevent that, but perhaps they are waving through the crops that purported to be 'resistant' but which as you've pointed out, could be carriers with minor or no symptoms.
I haven't bought a supermarket tomato for more than a decade.  But symptoms of disease on grocery produce of any kind is common enough.  Someone brought a pint of grocery store cherries to a party here over the holidays, and I was grossed out by the condition of some of them.  Brown spot on the side of one, even if it's not the virus it is nothing I want around my fruit.  I got rid of them rather than put in the cold compost pile.
It is interesting that someone was circulating a "milder strain" to inoculate plants.  I infer that there may be a risk that the active strain could combine with the worst one or simply evolve to increased virulence, that is if it was indeed milder as disputed by the authorities.  I have heard of strains of TSWV being mild but it isn't a subject I'm too familiar with, and whether there is a validated "vaccine" approach to plant viruses. 

Quote from: Nicolas on 2023-02-18, 08:39:21 AMWilliam, all tested accessions are available in the supplementary document :
https://static-content.springer.com/esm/art%3A10.1007%2Fs41348-021-00535-x/MediaObjects/41348_2021_535_MOESM1_ESM.xlsx (https://static-content.springer.com/esm/art%3A10.1007%2Fs41348-021-00535-x/MediaObjects/41348_2021_535_MOESM1_ESM.xlsx)

Oh that is really interesting. If you widen the scope of your germplasm search to the 40% category in the disease severity index column perhaps many more accessions are of interest. I notice lots of the Solanum habrochaites accessions in that category. I did a quick search of the few accessions I have in my tomato seed collection and none of the habrochaites had been tested but still the number of them with 40% rating is encouraging for a little bit of resistance possibility. Not a lot, but it could be additive.

This seems to be a good example of a case where we would want to breed in horizontal resistance, rather than vertical resistance.

Including a bunch of genes, each of which gives ~40% resistance through different biochemical pathways, would be a better long-term approach than finding a single super-resistant gene that could suddenly become susceptible after a single mutation of the TBRF virus.

So I am actually more excited about a bunch of ~40 resistant accessions than a single highly-resistant one.

I think even with the 20% category it is still more of the quantitative sort and tolerance not resistance. I think that is fine because tolerant plants can coexist with the virus. This is a case where it would be nice to have more resistant accessions as they could be additive.

It sounds like no one has identified a truly resistant (not just tolerant) gene or strain?

The paper about wild accessions identifies I think two strains of Solanum ocranthum with the ability to clear the virus after infection. So true resistance or a immune system response. However, transferring that might be a slog for a PhD tomato breeder with funding.

Some of the commercial large corporation efforts, some of which may have utility patents, also claim high levels of resistance but they don't reveal any details! The utility patents might reveal some details if we could find them.

Did some reading about this virus today, and regulations affected seed trade between Canada and US.  In fact you cannot send tomato or pepper seeds to the US from Canada any more without a phytosanitary certificate. I was surprised to hear that. 
But actually, the virus was identified in Ontario, Canada in 2019, and although it isn't widespread or anything like it, regulatory decisions are different between countries.  Both Canada and Mexico treat the virus as 'non quarantine' organism, that is to say, they do not test or restrict incoming market fruit.  But the US is in virus 'lockdown' so the intention is to contain or prevent any infection, and that means your incoming fruit crops should be well screened as well - ours are not (and apparently, there are currently no other imported crops being screened for disease which are meant for the table).
Looks like countries worldwide have put some restrictions on seed import/export to reduce seed transmission risks - This also explains the uptick in postal restriction on seed exchanges to the US.  You can't send any type of seeds by letter mail any more, it has to be parcel post with a declaration of contents.  Same chilling effect (cost of mailing parcel post) the other way too, from US to Canada.

Also found this recent work, which confirmed the pollen study cited above, that the virus is not in the embryo, only in the seed coat/endosperm layers.  As such the seedborne transmission rate depends on injuries that occur naturally during germination and infect the seedling in a small percentage of cases.  2.8% infection rate was found in this study n=500.  So that is pretty low.  Also, sterilant procedures do work to remove virus from the seedcoat.
https://mdpi-res.com/d_attachment/plants/plants-09-01615/article_deploy/plants-09-01615-v2.pdf?version=1606046733
So I think this is quite good news for the question, how big a risk are you facing of infection from random sprouted seeds from supermarket tomatoes that develop into virus carrying plants. And the opportunity is there, if really worried about contaminated seed, to use a seed treatment prior to planting.

I also suspect that, with such a low transmission rate in germinated seeds from infected fruit, the infection rate in resistant/asymptomatic plant seeds would probably be even lower???  It just stands to reason (but I may be wrong?) that virus load would be lower in a resistant and asymptomatic plant.

The other interesting thing is that this virus doesn't occur at all in the field crops in Canada.  It only occurs in greenhouses.   Documents from the EU and US also mention greenhouses specifically.  The problem is that in these environments where plants are continually pruned and tied in order to manage high densities, the virus spreads quickly and affects the whole crop.  And it's very persistent on surfaces, which puts your infrastructure investment at risk.  So here you have a virus problem that affects commercial greenhouse growers specifically because of the process involved in the cultivation design.  Even a small percentage of seed transmission could take down the intensive greenhouse crop.
But unless a home grower is using the same high pruning high contact designs, there's little chance of being affected in the same way.   If the virus did turn up on a plant that isn't being heavily pruned and daily handled along with others, you could (probably) effectively rogue it out early on, and contain the spread.

There is a possibility that some weed species could become a reservoir of virus carriers.  So there have been tests on experimental hosts.  Petunias, quinoa, tobacco and a few others.  If the virus became endemic in wild/weedy hosts, then it might start to turn up more often in a field situation.
The other scary issue I saw, is that the virus can be transmitted by bumblebees during pollination.  That would not be good!

Here is a useful reference for the symptoms you might look for to rogue out infected plants.

https://onlinelibrary.wiley.com/doi/10.1111/epp.12891?af=R

This one cites another 2022 study for the rate of seedborne transmission - only 0.08% !!

That sounds good. If ToBRFV doesn't spread easily in my outdoor growing non-pruning ways and I have some genes out there that could slow it down a bit and can disinfest seeds. It should be manageable if and when it gets here.

For the most part tomatoes die from frost here not disease.

I admit I am not one of those people who loves to prune, for starters.  But also in my early trials of heirlooms and OP's, I found that pruning cuts in cold wet seasons were associated with disease.  It's just too easy for a wound to become a site for the various molds.   True you can mitigate by dipping pruners in bleach every few cuts, but that is also an extra cost and hassle.  And the investment of time in pruning vigorous indeterminates is high.
So it didn't take much experience to settle on the idea of getting heirloom-worthy flavor into plants that don't require any pruning at all, and to focus on rugged cold tolerance and disease resistance for a grow that takes the least amount of labor.
No regrets on that decision!

Just saw this on a group. So it is definitely around. Thought it was pertinent to share here.

Oh, that is bad news!  I wonder how this happened, and where the F1 'Brandywise' seed is produced.

Just noted there's no mention of the virus issues on their page, although they say it's out of stock:
https://www.fruitionseeds.com/shop/vegetables/tomatoes/slicing-tomatoes/organic-brandywise-tomato/

One thing that specifically bothers me a lot about the commercial seed industry, is the production of seed in third world countries, where workers are paid very little and endure some bad work conditions as well.  Meanwhile there is a higher risk of the ToBRFV in the hot climate countries as well.  Of course if the alternative is greenhouse seed production, the same high risk applies.

"For the most part tomatoes die from frost here not disease."

I've seen it go both ways.  Some years the plants turn brown and stop producing leaves and fruit without quite dying, well before frost. Other years they keep producing right up until frost.

Amish Paste did that to me last year. Poor production of stems, leaves, and fruit, few tomatoes per plant, and tasteless. I won't grow them again.

This can actually be an advantage for those of us in the northern climates. The season is shorter, so less time for the plants to become fully infected, and the cold winter kill a lot of overwintering infectious agents. I don't compost tomato plants because of the risk of carrying infection, but just dump them in my woods well away from the garden. Viruses, bacteria, etc. will find it harder to survive on bare ground at 0 F (-18 C).

Keeping tomato plants disease-free during a long growing season sounds very challenging.

Ya I tried searching for more info and the only things I found was more posts by people talking about it that had bought them from there. Like reddit posts and forum posts.

I found it on their blog.  It was greenhouse produced, being an F1, not in their fields, and not affecting their other seeds.  Sad news all the same!
https://www.fruitionseeds.com/learn/blog/tomato-brown-rugose-virus-humbling-news-how-we-move-forward/

Also Sweet Prince F1 is infected

https://www.vegetables.cornell.edu/2023/05/12/tomato-virus-alert/

I tried so many disease resistant tomatoes to overcome the disease we have in our community garden. Ankara/ Turkey 7b. Nothing worked. I posted pictures in tomatoville and eventually realized that it was tobrfv. After reading somewhere that some wild cultivars was resistant I tried  wild tomato crosses I purchased from EFN. These were wilding panamorous (WP) and Q-series panamorous (QP) and I believe one other. First year I tried 3 plants of WP. One died but not because of tobrfv.  The other two were extremly profilic and had no disease. Every other tomato including galahad and big beef died of the disease. The fruits of this tomatoes were small and the taste was bland. This year I only tried WP and QP and a commertial variety that claimed some resistance. That commercial variety showed little resistance and died. Some of WP's this time got the disease.  Some only had it on the leafs while some on the fruits and I ended up culling them. Remaining WP's had again small off tasting tomatoes (to my taste) and I let the neighboors have them. Many of the QP's eventualy got the disease but two black ones and a pink one were not effected at all. They had sunburn so I had to provide some shade. While the fruits were perfect looking taste was just average. I collected seeds and I will try to cross them with now commercially available tobrfv resistant high brix cherry varieties to improve their taste.

Atilgan, that is very cool! Joseph worked hard to create populations like those as part of his promiscuous tomato project. So it is very neat that they had some utility for this problem of the brown rugose fruit virus.

I hope the commercial tobrfv tomatoes are another good source of genetics and that the corporations involved are not legally protecting them from use for breeding.

When this problem first came to my attention a few years ago (Thanks to Reed) I looked around for genetics and all I was able to get to use was an accession of current tomato called LA1375 that is known for having some tolerance. I've crossed it into my tomatoes in anticipation that the virus may get here sometime. I've shared some of that seed with the Experimental Farm Network. I have a great deal of tomato genetics from Joseph's promiscuous project so it is good to hear that there may be some resistance or tolerance in those genetics as well.

Quote from: William Schlegel on 2022-01-11, 06:10:38 AMhttps://link.springer.com/content/pdf/10.1007/s41348-021-00535-x.pdf (https://link.springer.com/content/pdf/10.1007/s41348-021-00535-x.pdf)

New article about (ToBRFV) The Brown Rugose Fruit Virus listing some resistance that has been found from 636 wild species accessions found about 31 resistant accessions or about 5 per 100 accessions.

I also notice that many galapagense got 60% disease severity there, including LA1410. LA1400 impressively got 20%. Cheesmaniae LA1409 was 40%.

I'd be curious if these kind of percentages of 40~60 are enough to be of significant value in an outbreak.

Then, did any of you notice this article? Same authors - Evaluation of responses to tomato brown rugose fruit virus (ToBRFV) and selection of resistant lines in Solanum habrochaites and Solanum peruvianum germplasm - 2022
https://link.springer.com/article/10.1007/s10327-022-01055-8

QuoteReactions of plants in 173 wild tomato accessions belonging to Solanum habrochaites and S. peruvianum were studied by inoculation with a tobamovirus, tomato brown rugose fruit virus (ToBRFV). Around 10–50% of plants in nine accessions of S. habrochaites and one of S. peruvianum were demonstrated to be highly resistant. Resistant plants showed no symptoms at 22–24 °C, and no virus could be detected in their inoculated and newly developed leaves using bioassays and RT-qPCR. ToBRFV-resistant plants were also resistant to tobacco mosaic virus and tomato mosaic virus.

QuoteSymptomatological observations revealed that following three inoculations with ToBRFV, a number of plants in nine accessions of S. habrochaites (LA1738, LA1739, LA2171, LA2541, LA 2812, PI 308,182, PI 379,012, PI 379,014 and PI 390,659) and one of S. peruvianum (PI 308,181) remained symptomless both locally and systemically after 40 dpi (Table S1). The presence of asymptomatic and symptomatic individuals at different frequencies (2–10 resistant plant out of 15 inoculated) clearly showed that these accessions segregated for the type of reactions to the virus (Fig. 2). No symptoms were also detected in the cuttings that originated from rooted shoots of the symptomless plants after inoculation with TMV and ToMV after 40 dpi (data not shown).

So any of that material might be of interest.

Then addressing the above comment:

Quote from: atilgan on 2023-12-24, 03:35:45 PMThese were wilding panamorous (WP) and Q-series panamorous (QP) ...

Wow that's cool they showed some resistance, and a funny coincidence this thread came to life today just as i was reading up on this disease!

Here is a  picture of wild panamorous one is effected and one is healthy
http://www.agaclar.net/forum/1623274-post1489.htm

I don't know how long tobrfv stays in the soil, but other mosaic viruses can survive for more than 10 years.

Perhaps you can try and cross many of the resistant tomato ancestors and after a few years use the most resistant as rootstock. Hopefully the virus will not be transported from the soil to the susceptible varieties.

Quote from: atilgan on 2023-12-25, 02:02:08 AMHere is a  picture of wild panamorous one is effected and one is healthy
http://www.agaclar.net/forum/1623274-post1489.htm (http://www.agaclar.net/forum/1623274-post1489.htm)

Solanum pimpinellifolium accession LA1611 in the above studies got 0~20% disease severity. It's available at Nordgen genebank listed as NGB 22603, here's their page on it:

https://www.nordic-baltic-genebanks.org/gringlobal/accessiondetail?id=42807

For breeders in Europe this could be useful perhaps - or does anyone know a more resistant one available in Europe? I couldn't find any but it's not easy to search. Anyway, Atilgan perhaps crossing some large tomatoes with this (maybe in a place where you can at least grow to cross, free from the virus until you get F2), could be useful for your community?

It would also be really interesting to know how plants like that pimp or others from the studies, compare to those Wildings and Q series, in gardens known to have this disease. Then we would have some kind of way of measuring their resistance relative to those with known resistance.

Roland are you working with this disease resistance also? It sounds like it could be good to add, if possible, this to resistance to our projects. Would be sad to see hard work of late blight projects go to waste if our regions get overwhelmed with this one too!

I made a cross between my two 2022 pimp crosses in 2023. It should segregate for visible characters like fruit size and color just as if it was either of the parent crosses but it has potential for both brown rugose fruit virus tolerance and late blight resistance. I also crossed my LA1375 cross to my cross with Purple Zebra F1.

LA1375 is the accession with some tolerance I was able to request from USDA-ARS-GRIN. I think I've now managed fifteen crosses with it.

LA1375 Crosses:

MMM x LA1375
Dwarf Gloria's Treat x LA1375 & PH5 pimp pollen mix
(MMM x Purple Zebra F1) x (MMM x LA1375)
 (MMM x PH5 LB pimp) x (MMM x LA1375)
 Fisher's Earliest Paste x (MMM x LA1375)
 Ida Gold x (MMM x LA1375)
 (MMM x Sweet Cherriette) x (MMM x LA1375)
 Dwarf Eagle Smiley x (MMM x Brown Rugose LA1375)
Wilford x (MMM x Brown Rugose LA1375)
Bison x (MMM x Brown Rugose LA1375)
MMS x (MMM x LA1375)
MMM x (MMM x LA1375)
(MMM x LA1375) x (MMM x galapagense X)
Payette x (MMM x LA1375)
Hoosier Rose x (MMM x LA1375)

Also for those in Europe, habrochaites accession PI 308182 segregated for total resistance, and for breeders can be found here:
https://cgngenis.wur.nl/accessiondetails/CGN23951

This is great work, guys.  Very exciting Atilgan, that you've been able to identify some resistant plants to work with in the situation of an endemic virus. Please make lots of crosses with delicious tomatoes!

I had 2 more thoughts on this topic.
1) Wild vs commercial
If some of those new commercial varieties are genuinely as resistant against ToBRFV as the most resistant wild accessions, i.e. having none of the virus in them at all when exposed to it, then wouldn't it be better to cross with them, rather than the wild ones? I.e. isn't it easier to breed out the undesirable traits from commercial tomatoes such as poor taste, than it is the undesirable traits from wild species like tiny size and in some cases disgusting taste?

On that point, does anyone know a way of obtaining any totally resistant commercial varieties, whether it be through purchasing seeds or actual fruits and self-harvesting their seeds?

Quote from: atilgan on 2023-12-24, 03:35:45 PMThis year I only tried WP and QP and a commertial variety that claimed some resistance. That commercial variety showed little resistance and died.

Which commercial variety did you try? And are there any which claim total resistance that are available in your area, like they seem to be in Israel?

2) Regarding total vs partial resistance
If we breed varieties or populations with only partial resistance, then if we do get the virus, does that not mean that from that point onwards, unless we are growing indoors and can sterilise the entire grow area including the building and soil, we are then basically unable to sell or share any tomatoes or seed? Because, so long as our tomatoes are not 100% resistant, having none of the virus, we may be sharing infected material. In which case, aside from the case of personal eating or in a case where the entire region might be infected and the virus becoming endemic (or in preparation for that time), so long as the spread of the virus is to be avoided, is it not rather pointless to have mere partial resistance?

Quote from: Justin Jardinier on 2023-12-28, 07:26:51 AMI had 2 more thoughts on this topic.
1) Wild vs commercial
If some of those new commercial varieties are genuinely as resistant against ToBRFV as the most resistant wild accessions, i.e. having none of the virus in them at all when exposed to it, then wouldn't it be better to cross with them, rather than the wild ones? I.e. isn't it easier to breed out the undesirable traits from commercial tomatoes such as poor taste, than it is the undesirable traits from wild species like tiny size and in some cases disgusting taste?

On that point, does anyone know a way of obtaining any totally resistant commercial varieties, whether it be through purchasing seeds or actual fruits and self-harvesting their seeds?

2) Regarding total vs partial resistance
If we breed varieties or populations with only partial resistance, then if we do get the virus, does that not mean that from that point onwards, unless we are growing indoors and can sterilise the entire grow area including the building and soil, we are then basically unable to sell or share any tomatoes or seed? Because, so long as our tomatoes are not 100% resistant, having none of the virus, we may be sharing infected material. In which case, aside from the case of personal eating or in a case where the entire region might be infected and the virus becoming endemic (or in preparation for that time), so long as the spread of the virus is to be avoided, is it not rather pointless to have mere partial resistance?

To me, using commercial varieties as a source of resistance is a legal question only. Is it legal to breed with this variety? I suspect that it is still true that much of the time it is still fine. Though there are legal questions there where you could be potentially violating an MTA or something. Carol Deppe when she proposed her breeding scheme for late blight was very concerned about the bad taste of Iron Lady F1 and proposed an elaborate methodology to breed that out. For ToBRFV the situation would be potentially the same with whatever resistant varieties found. However, this should be much easier than working with wild species.

As far as obtaining one: This might be as simple as buying a seed packet for many growers in heavily infested regions. These tomatoes as near as I can tell, were at least initially, being marketed exclusively where they are needed most. Mexico, Israel, and Turkey amongst others. So I am not sure if in USA or Britain we can yet purchase a seed packet. However, it could be that a grocery store tomato from say Mexico would be both a potential source of infection and a potential source of resistance or tolerance. Though I would be fairly uncomfortable breeding with that unknown of germplasm because it could have legal implications. Or not! I would need some good advice on that point. However, if someone a little more knowledgeable could pave the way it would be very interesting to have something equivalent to Purple Zebra F1 or Galahad F1, that is legal to breed with, with a resistance gene or genes for this disease.

I bred mere tolerance into mine because it was the only accession I could get from the publication of tolerant and resistant accessions that was first shared. Someone shared that some growers had a clever work around- they basically bred a weak strain of the virus and infected their plants with it to out compete the more virulent strains. Their government did not accept that work around- but it worked. Having tolerant tomatoes would be much the same. You would still have, and potentially be spreading the virus once you got infected. One potential positive would be that you could still work on your breeding projects. You might also be able to disinfest your seeds and return to an uninfected status. In a practical sense, if the virus becomes globally widespread enough it won't matter anymore, and everyone will need tolerance and or resistance. We would lose non-resistant heirlooms.

Several big seed producers have now tobrfv resistant varieties. Some of them claim high resistance while others only partial resistance. Most of them are cherry type. Fito for example tested his cherry varieties and 4 of them have intermediate resistance. Two of these cherries had taste awards from customers. They are available in europe but not in small quantities. Rijkz Waan now has  several cherry varieties with high resistance but again only for professional producers. USA site also list several varieties
https://www.rijkzwaanusa.com/vegetable-seeds/tomato/amelioso-rz-f1-72-ck0619-prdSL12162-ctgCrops.tomato
Harmoniz have several with very high brix up to 9.
https://www.harmonizseed.com/product/dormaplum-2/
Hazera and other major companies have them as well. As I said I tested one commertial variety last year and it failed miserably but I did not purchase the seeds from a trusted source.

By the way I was  getting fito resistant variety solemino from amazon spain but then I realized that it is just another tomato with the same name. Here is the link for Fito

https://www.hortidaily.com/article/9506744/tobrfv-resistant-cherry-pear-and-bouquet-tomato-varieties/

Patent pending on the high resistance qtl and markers, for seeds offered here:
https://nrgene.com/traits/tobrfv-high-resistance-source/

I wonder if the patent would interfere with OSSI pledge.   If not, well you could buy the seeds and even the backcross with marker assist which they offer, given a budget for that.
Someone should talk to them and see whether the patent would bar the offspring from being OSSI pledged and freely used for further breeding.

The patent : https://patents.google.com/patent/US20230345900A1/

They've also filed one in Europe. Good luck to get it approved here (though we have a few outrageous ones already accepted) ...

Quote from: Nicolas on 2023-12-29, 11:48:53 PMThe patent : https://patents.google.com/patent/US20230345900A1/ (https://patents.google.com/patent/US20230345900A1/)

Wow that also states:

QuoteThe symptoms of the new virus included mild foliar symptoms at the end of the season, but strong brown rugose symptoms on the fruits. A later publication showed that the virus was also present in Israel in 2014, and it was established that the virus can also infect pepper (Capsicum annuum) plants (see "A new Israeli Tobamovirus isolate infects tomato plants harboring Tm-22 resistance genes." Luria et al; PLoS ONE 2017).

I wonder how serious that issue is, do we need to be worrying about peppers too? If so I'd be really interested if C. chinense and C. baccatum are more resistant or not.

I found this from 2020:
file:///Users/justin/Downloads/syn_syngenta_qa_-_tobrfv_-_external.pdf

QuoteIt infects tomato and pepper. Unlike other Tobamoviruses it breaks the widely deployed Tm2-2 gene in tomato providing resistance to TMV and ToMV. In public information the pepper L-genes providing Tobamovirus resistance are sometimes suggested to be effective against ToBRFV. This is however not yet supported with scientific evidence and may make pepper materials even be a hidden source of infections if pepper is not taken into account sufficiently.

QuoteThe impact of ToBRFV on pepper crops so far seems to be low.

And this sounds rather important information:

QuoteHealth treatments
All tomato and pepper seed lots receive a sanitation treatment active against Tobamoviruses within the seed extraction process. On tomatoes, Sodium Hypochlorite and Trisodium Phosphate treatments are applied, effective against bacteria and viruses. On peppers, Trisodium Phosphate treatments are applied.

It's starting to sound like C. chinense and C. baccatum might be alright. Here's another article:
https://archive.ahdb.org.uk/knowledge-library/the-symptoms-of-tomato-brown-rugose-fruit-virus-tobrfv

QuoteTomato is a major host of ToBRFV, but inoculation trials have demonstrated that sweet pepper (Capsicum annuum) as well as the experimental host plants Nicotiana species, Solanum nigrum, Chenopodium quinoa, Petunia hybrida and Chenopodium murale can act as minor hosts showing slight symptoms.

And:

QuoteSymptoms in sweet pepper
ToBRFV in sweet pepper is less common, but you should remain vigilant for any unusual symptoms in your crop. To view images of symptoms in sweet pepper crops (and further images in tomato crops), visit EPPO's ToBRFV gallery.

That gallery has many photos from around the world, including some infected peppers, found here:
https://gd.eppo.int/taxon/TOBRFV/photos

Here's one of the pepper photos, from Palestine:
(https://gd.eppo.int/media/data/taxon/T/TOBRFV/pics/1024x0/10220.jpg)

For anyone interested, here's the 2022 paper Pepper Plants Harboring L Resistance Alleles Showed Tolerance toward Manifestations of Tomato Brown Rugose Fruit Virus Disease:
https://www.mdpi.com/2223-7747/11/18/2378

Now back to that patent Nicolas shared:

QuoteIt is another object of the present invention to disclose the tomato plant as described above, wherein said ToBRFV-resistant wild tomato plant is selected from a group consisting of LA0107 (S. corneliomulleri), LA0361, LA1918, LA2650 (S. habrochaites), LA1938, LA1969, LA2748, LA2755 and LA2931 (S. chilense).

I decided to check these accessions in the paper Screening of Solanum (sections. Lycopersicon and Juglandifolia) germplasm to ToBRFV - Ahmad Jewehan - 2021. Here's the disease severity given for those I could find:
corneliomulleri LA0107: 80% - that surprised me that they used that, even though it gave such poor results in that trial. There were 4 corneliomulleri accessions that had only 40%, and several with 60%.

habrochaites LA2650: 40% - again surprising. There were 2 segragating 0~20%.

chilense LA1938: 40%
chilense LA1969: 60%
chilense LA2748: 60%
chilense LA2755: 80%
chilense LA2931: 60%
These again, surprising since there were 3 with 20% and one segragating 0~20%.

That leaves habrochaites LA0361, LA1918, the former of which was used in the paper Evaluation of responses to tomato brown rugose fruit virus (ToBRFV) and selection of resistant lines in Solanum habrochaites and Solanum peruvianum germplasm - Ahmad Jewehanet al - 2022. Note this is by the same authors as the paper above but tests different accessions.
LA0361: 40% - that paper has 2 with 20% and 9 segragating 0~40%, plus the 2 segragating 0~20% in the previous paper.

So I'm really curious why they used all these accessions that have significantly less resistance than numerous others from the same species.

The only other reference I could find to LA1918 was in a paper Tomato Brown Rugose Fruit Virus Pandemic in Annual Review of Phytopathology (perhaps an interesting read for many folk here), by the same 2 lead authors of the above 2 papers, published June 2023:
https://www.annualreviews.org/doi/10.1146/annurev-phyto-021622-120703

Incidentally that paper gives this map:
Screenshot 2023-12-30 at 12.54.21.png

Note that map is incomplete. As the article states:

QuoteToBRFV has been detected on tomato seeds imported from Japan into the Netherlands (44) from Taiwan into Greece (45), from Thailand into the United Kingdom (38), from Peru into the Netherlands (37, 44, 57), from India into the Czech Republic (45), from Lithuania into the United Kingdom (57), from Australia into Spain (45), and from Ethiopia into the Netherlands (44). It has also been detected on pepper seeds imported from Taiwan into the Czech Republic (45), from Thailand into Spain (44), and from Japan into Spain (46) as well as on tomato and pepper seeds imported from India into Italy (38, 44) and from Slovakia into the Czech Republic (46). This suggests that ToBRFV is most likely present in these countries (Japan, Taiwan, Thailand, Peru, India, Lithuania, Ethiopia, Slovakia, and Australia) even if the virus has not been officially reported yet.

Anyway back to the patent and that one accession, LA1918 - that paper only made mention of it in reference to that patent! Also, I now see that patent was filed  on 2021-09-22, so they were clearly working on all of that before these more recent studies were published, which would seem to explain why they may not have been aware that there are many accessions with far greater resistance than the ones they used. This implies that we might be able to get better resistance than them perhaps, by using better wild sources.

Regarding that map of global distrubution, the source has been updated on 2023-12-21 and can be found here:
https://gd.eppo.int/taxon/ToBRFV/distribution

I have added to that the countries the paper added where seeds imported from those countries have been shown to have the virus. I was unable to split countries or kingdoms into constituent parts so have coloured the whole rather than leaving them out. And I used just one colour.
Screenshot 2023-12-30 at 14.00.01.png

The patent talks about crossing and backcrossing amongst the accessions with resistance, so not impossible they were able to improve resistance by additive effects.
I think the main point of the patent is that the resistance is coming from a dominant or partly dominant gene.  This would mean it can be used to create F1s with resistance even when crossing to a susceptible plant.   Similar disease resistance patents are noted at the end, belonging to big seed companies.

It certainly looks as though disease resistance traits are routinely patented now.
Whether those patents also restrict their use in breeding, I'm not clear.
Obviously they have done the work to scoop up resistance traits from wild relatives and put that into a crop type tomato.  They are selling the seeds and marker assist to breeders, along with intellectual property rights it appears.   The patent gives them some exclusive rights to those seeds and the marker assist they developed for their offering.
Still I see they have an office in Saskatoon (Canada) where patents that restrict breeders rights are not permitted in the law.   So I can only assume they can offer products and services here without the necessity of that restriction..
I just don't understand how it all works.

QuoteEvaluation of Tomato Germplasm against Tomato Brown Rugose Fruit Virus and Identification of Resistance in Solanum pimpinellifolium (https://www.preprints.org/manuscript/202401.0785/v1)

In the present study, we evaluated a total of 476 accessions from 12 Solanum species and
identified 44 accessions with resistance/tolerance to ToBRFV in five species, including S.
corneliomulleri, S. habrochaites, S. peruvianum, S. subsec. lycopersicon hybrid, and S. pimpinellifolium.
Upon closer examination and comparison with earlier reported studies, the 44 accessions identified
in the present study appeared to be new additions, which enrich the genetic pool for selection in
tomato breeding. To our knowledge, this is the first report to identify S. pimpinellifolium with true
resistance to ToBRFV.

QuotePlant ID Taxonomy Disease severity index (%)
PI 129144 Solanum corneliomulleri 0
PI 126445 Solanum habrochaites 17.6
PI 209978 Solanum habrochaites 0
PI 247087 Solanum habrochaites 0
LA 2107 Solanum habrochaites 0
PI 306811 Solanum peruvianum 16
PI 390667 Solanum peruvianum 0
PI 390671 Solanum peruvianum 0
PI 127805 Solanum pimpinellifolium 14.2
PI 143524 Solanum pimpinellifolium 14.2
PI 143527 Solanum pimpinellifolium 0
PI 211838 Solanum pimpinellifolium 0
PI 230327 Solanum pimpinellifolium 0
PI 344102 Solanum pimpinellifolium 0
PI 344103 Solanum pimpinellifolium 0
PI 346340 Solanum pimpinellifolium 0
PI 390692 Solanum pimpinellifolium 0
PI 390693 Solanum pimpinellifolium 0
PI 390694 Solanum pimpinellifolium 0
PI 390695 Solanum pimpinellifolium 0
PI 390698 Solanum pimpinellifolium 0
PI 390699 Solanum pimpinellifolium 18
PI 390700 Solanum pimpinellifolium 0
PI 390702 Solanum pimpinellifolium 11.4
PI 390710 Solanum pimpinellifolium 0

I had a look at the peruvianum PI 308181 that was highy resistant to ToBRFV in the paper Evaluation of responses to tomato brown rugose fruit virus (ToBRFV) and selection of resistant lines in Solanum habrochaites and Solanum peruvianum germplasm - Ahmad Jewehanet al - 2022.

Here are images:
https://npgsweb.ars-grin.gov/gringlobal/accessiondetail?id=1230210

I was really surprised, it looked extremely unusual for a peruvianum, to me. The flowers looked more like habrochaites, and the fruits were hairy like habrochaites. So I looked deeper. On the 'passport' page there is this note:

QuoteResemble S. habrochaties (May, 2023). Note from Shai Koussevitzky: We received seeds of PI 308181 from the USDA collection. According to the GRIN web site, as well as literature, this accession is a S. peruvianum. However, I attached some images from which it is clear that this is a S. habrochaites and not S. peruvianum. We will re-check our work to make sure that we did not mix the accessions in our multiplication process. Note from Yousoon Baek, PhD: As I reviewed the images, I noticed that the plants with flower and leaf morphologies appear to resemble S. habrochaties more, as mentioned by Shai. While I cannot confirm this based on the images alone, both S. per and S. hab are genetically and morphologically divergent species (There should be some genetic markers available to identify those species). Generally, the petals on S. hab flowers lack separation at the tips, as shown in the figures, while S. per has more separated petals that often bend backward. Additionally, S. per usually has more serrated leaflets compared to S. hab, which usually has a wider leaflet shape, as shown in the figures. Although the morphologies in the images contain more characteristics of S. hab, they have much fewer trichomes on the leaves or stems than I typically associate with S. hab. If any of the fruits become a mix of purple and green, that would be more characteristic of S. per, whereas if they remain green with lots of hairs, they will be more like S. hab. I have attached the figures of tomato morphology guidelines.

And, I noticed that in this new paper:

Quote from: Nicolas on 2024-01-16, 11:34:02 PMEvaluation of Tomato Germplasm against Tomato Brown Rugose Fruit Virus and Identification of Resistance in Solanum pimpinellifolium (https://www.preprints.org/manuscript/202401.0785/v1)

... peruvianum PI 127832 scored 100% disease severity whereas in Evaluation of responses to tomato brown rugose fruit virus (ToBRFV) and selection of resistant lines in Solanum habrochaites and Solanum peruvianum germplasm it scored 60%.I was only checking some specific accessions but that's interesting to note anyway, it may mean that the scored are set in stone.

Also in this newest paper, aside from the ones with 0%, those with 20% may still be valuable. Here's the TGRC ones of those:
20 percent.png

There were also many 20% scores from the USDA material.

I plan to make some crosses with these in 2024 for this project:

PI 129143
PI 143527
PI 233930
PI 379006 LA1385 Solanum lycopersicum L. var. cerasiforme
PI 390713 W-C 1292
PI 390714 W-C 1293
PI 390716 W-C 1295
PI 390717 W-C 1296

Quote from: William Schlegel on 2024-02-19, 09:43:32 PMI plan to make some crosses with these in 2024 for this project:

PI 129143
PI 143527
PI 233930
PI 379006 LA1385 Solanum lycopersicum L. var. cerasiforme
PI 390713 W-C 1292
PI 390714 W-C 1293
PI 390716 W-C 1295
PI 390717 W-C 1296

Only one cross so far and it wasnt ripe quite yet last I checked. Maybe more next year.

Finally picked the cross dwarf red regular leaf (Mocha's Cherry x Mission Mountain Sunrise) x PI390714 current tomato. Should be a nice addition to the cherry tomato grex. It is a nice big large cherry sized fruit so hopefully it has lots of seed in it. Will find out.

Going to have to read all this thread soon now that ToBRFV has been confirmed in Australia, from a seed lot that tested negative no less.

Quote from: whwoz on 2024-10-19, 01:06:38 PMGoing to have to read all this thread soon now that ToBRFV has been confirmed in Australia, from a seed lot that tested negative no less.

Oh that is concerning. Not sure where you would get resistance genes there?!

Was it you that was saying there are large patches of wild current tomatoes naturalized in Australia? With extremely large population sizes there might be some potential for a useful resistance or tolerance trait to arise even if it isn't currently present. Though also a potentially huge reservoir for the virus.

Here is my update
I trailed three hybrid varieties claiming resistance (two f1 and one f2). I obtained Vitrin f2 seeds from a store-bought tomato during winter. Vitrin f2 did not segregate much in terms of look but each one tasted different with nothing special. Store bought tomato had ok taste. If I could obtained f1 maybe it would have tasted a lot better with my growing conditions.  f1 tomatoes had everything going for them but tasted bland.  Wilding panamorous  and Q-series panamorous again tasted bland. I did not have a chance to do any crosses. There are so many varieties available, but I could only find two varieties in small quantities.
Here are the varieties first two around 20 gr. Last one is around 140 gr.
https://www.yukseltohum.com/tr/urunler/vitrin-f1
https://www.yukseltohum.com/tr/urunler/domates-tohumu-103/kokteyl-114/margol-f1
https://yukseltohum.com.tr/tr/urunler/domates-tohumu-103/spesiyal-117/elips-f1

The disease's presence was not as severe this year.  One unknown superb tasting but very small yellow cherry tomato that planted in tree different gardens one of which had infested plants showed no disease.  Several Green zebra planted in my neighbors's garden showed no disease. These need to be tasted again next year.

Quote from: atilgan on 2023-12-24, 03:35:45 PMI tried so many disease resistant tomatoes to overcome the disease we have in our community garden. Ankara/ Turkey 7b. Nothing worked. I posted pictures in tomatoville and eventually realized that it was tobrfv. After reading somewhere that some wild cultivars was resistant I tried  wild tomato crosses I purchased from EFN. These were wilding panamorous (WP) and Q-series panamorous (QP) and I believe one other. First year I tried 3 plants of WP. One died but not because of tobrfv.  The other two were extremly profilic and had no disease. Every other tomato including galahad and big beef died of the disease. The fruits of this tomatoes were small and the taste was bland. This year I only tried WP and QP and a commertial variety that claimed some resistance. That commercial variety showed little resistance and died. Some of WP's this time got the disease.  Some only had it on the leafs while some on the fruits and I ended up culling them. Remaining WP's had again small off tasting tomatoes (to my taste) and I let the neighboors have them. Many of the QP's eventualy got the disease but two black ones and a pink one were not effected at all. They had sunburn so I had to provide some shade. While the fruits were perfect looking taste was just average. I collected seeds and I will try to cross them with now commercially available tobrfv resistant high brix cherry varieties to improve their taste.

The survival of some green zebra is interesting. Tolerance / resistance seems unlikely especially if it is just some of the plants. Virus could be skipping plants or a mild strain of the virus could be spreading and competing with the virulent strain for hosts. Which is what some greenhouse growers were deliberately innoculating their crops with.

Returning to good flavor should be possible if susceptible plants with good flavor could be crossed back in still? Does a susceptible plant make it to flowering? What varieties did you particularly like the flavor of that you can't grow now?

Quote from: William Schlegel on 2024-10-18, 08:20:14 PMFinally picked the cross dwarf red regular leaf (Mocha's Cherry x Mission Mountain Sunrise) x PI390714 current tomato. Should be a nice addition to the cherry tomato grex. It is a nice big large cherry sized fruit so hopefully it has lots of seed in it. Will find out.

It had about 40 seeds which are now in an envelope. The mother strongly favored dwarf Mocha's Cherry being dwarf, regular leaf, antho skinned, and Mocha/purple/chocolate/black colored flesh. My strategy is to try to cross these resistant and tolerant current tomatoes with a broad assortment of tomato types of OSSI pledged descent before the virus spreads to here- if it does.

I used to plant mostly pink and purple type tomatoes such as Black Krim and Brandywine. In our hobby garden (7b very dry with cool nights) it usually shows itself while tomatoes start ripening.

Ah so you could still cross to them even with the disease present! That is important that you could still work with Black Krim and Brandywine. Those are very popular tomatoes even here. My mom really likes Black Krim. I don't think brandywine develops good flavor here with our cool nights and it ripens late which may mean they are ripening with even cooler nights and potentially some rain to cause splitting. Though I've known folks to even raise seed crops of both here.

It seems that I have made 27 crosses and crosses with those crosses towards breeding in tolerance and resistance.

The following is the number in my tomato inventory a space then the cross, and another space and a brief note on what I think might segregate out of the cross. MMS of course standing for the MMS type which is a blue skinned yellow red marbled bicolor potato leaf.

283   MMM x Brown Rugose LA1375   MMS 286   Dwarf Gloria's Treat x Currants   BICOLOR 302   (MMM x Purple Zebra F1) x (MMM x LA1375)   STRIPES, Purple/Chocolate/black 303   (MMM x PH5 LB pimp) x (MMM x LA1375)   MMS 304   Fisher's Earliest Paste x (MMM x LA1375)   LONG 305   Ida Gold x (MMM x LA1375)   YELLOW 306   (MMM x Sweet Cherriette) x (MMM x LA1375)   EARLY 314   Dwarf Eagle Smiley x (MMM x Brown Rugose LA1375)   TASTY Yellow 316   Wilford x (MMM x Brown Rugose LA1375)   MMS 317   Bison x (MMM x Brown Rugose LA1375)   MMS 320   MMS x (MMM x LA1375)   mms 331   MMM x (MMM x LA1375)   mms 355   (MMM x LA1375) x (MMM x galapagense X)   MMS Orange 366   Payette x (MMM x LA1375)   MMS 369   Hoosier Rose x (MMM x LA1375)   MMS 494   Galapagos Pear x 303?   pear 495   Dwarf Mocha's x MMS x MMR x 303?   yellow, blue, chocolate 496   MMR X DGT X Current   YELLOW BLUE 497   Puerto Cortes x 303?   MMS 498   MMR Dwarf x 303?   Yellow, Blue 499   Dwarf Moby's x 303?    Yellow, bLUE 500   Dwarf Johnson's Cherry x 303?   yELLOW bLUE 501   Mocha's x MMS x 303?   YELLOW, BLUE, chocolate 504   Glacier x 320 MMS x (MMM x LA1375)   MMS 508   366 x 358   MMS 511   (Dwarf Mocha's x MMS) x PI 390714 brown rugose true resistant pimp   Black 513   nodak early x 303?    early MMS thick walls?

My general goal with all these crosses was to hopefully preserve some of my favorite tomato genetics should we ever be hit hard by the virus. My hope is also that by making new crosses and thus preserving and selecting from more lines- that some of those resulting lines would have the resistance. I also hope to continue making new crosses with virus resistant material.