Do you guys think FMV from figs can be spread to say citrus? I have no idea, sorry if this is a silly question!

It is just that I was quarantining an FMV fig next to citrus and the citrus leaves I believe were undernourished at the time and showed some yellowing spots more indicative of undernutrition than FMV...but FMV crossed my mind since I guess there is a tobacco version of the virus and mosaic viruses for a bunch of different plants... I am some 80% sure it was just undernutrition.

I read somewhere recently some people think that FMV was from a citrus MV.  I don't remember the site I read it on.  It might have been an ag site of sorts - not and individual business or blog.

I know that say cucumbers can get tobacco mosaic virus and tomatoes can get cucumber mosaic virus so it is possible in theory but if my understanding is correct, the viruses to infect inter species must be in the same family of viruses that affect the original host plant, although this may be false and I may be corrected.

There is no evidence that FMV or any of the other FMD (fig mosaic disease) associated viruses that have been identified can spread to citrus. None of the genetic sequences of the fig viruses generated to date show any significant similarity to citrus viruses according to the scientists publishing the FMD viruses' gene sequences with one exception, which is Fig Badnavirus (FBV-1). FBV-1 is most closely related to two other badnsviruses, Cacao swollen shot virus and Citrus yellow mosaic virus. By analogy to other viruses having similar levels of evolutionary related where coss-infection has been studied, it would be surprising if FBV-1 can infect citrus. Of the viruses isolated from fig trees that are known to cause FMD, FMV-1 is in the genus Emaravirus. It is transmitted by the eriophyid mite Aceria ficus. There is a study showing that a FMD virus presumed to be FMV-1 can cause disease in some other species of ficus, but not all other species of ficus, another indication that it can not infect citrus. Other examples of emaraviruses are European mountain ash ringspot-associated virus, rose rosette virus, raspberry leaf blotch virus, pigeonpea sterility mosaic virus, yam mosaic virus and maize red stripe virus. All of those plant hosts are pretty distant to fig. There is no evidence these viruses are able to infect each others host plant. Every family of viruses is different, but wide host susceptibility is pretty unusual. Other FMD viruses isolated to date fall into the genera closterovirus, leutovirus, umbravirus  and cryptic virus. Other closteroviruses are transmitted by aphids and, by analogy, these fig viruses assumed to be transmitted by aphids too. Badnaviruses are transmitted by aphids and mealy bugs and FBV-1 is assumed to be transmitted by aphids too. I have only had time to compare Emavirus and Badnavirus family nucleic acid sequences. While the viruses within each genus are clearly evolutionarily related, the separation between them indicates they have been associated with their respective hosts for many, many thousands of years. Portions of this with some attached references were discussed in this thread:
http://figs4funforum.websitetoolbox.com/post/Does-FMV-persist-in-soil-6142400

Chivas, the tobacco, tomato and cucumber mosaic viruses are a pretty interesting case. They are all members of the genus Tobamovirus. They differ from most other plant viruses in that they primarily are transmitted mechanically instead of through insect vectors. The many isolates of these viruses actually show a progression of genetic sequences as you move from on isolate to the next. The result is you have examples where it is not entirely clear if it is a tobacco or tomato MV, a tobacco or cucumber MV, or a tomato or cucumber MV. I think if you really start to study the relatedness of the tobamoviruses, you would conclude that there is little similarity between how they go about their business and how FMD viruses go about theirs. It is a really interesting system none-the-less.

If anyone wants scientific references on all this, I am happy to share.

Good luck with your trees!

In my greenhouse (commercial production) I have sent off eliza tests for viruses and it comes back saying it has identified tobacco mosaic virus, but you are saying that it may not be the case of actual TMV?  This really peaks my interest as affects me greatly.  

Chivas, The ELISA (enzyme linked immunosorption assay) you had run uses antibodies directed against a particular protein to identify the presence or absence of that protein and the organism that goes with it. You can also use the assay to identify the concentration of the particular protein. The accuracy of the identification of anything by ELISA, TMV in your case, depends on the specificity of the monoclonal antibody or anti-sera used. Since the ELISA identified TMV, there a a few questions you can ask the testing lab that will allow you to know how confident you can be in the test's accuracy. The first would be are they using a monoclonal antibody or an antisera for this assay? Antisera tend to show more cross reactivity than monoclonal antibodies. Second, what other tobamoviruses did they test cross reactivity on? There are at least 19 tobamovirus strains including ribgrass mottle virus, pepper mild mottle virus, odontoglossum ringspot virus, oilseed rape mosaic virus, clitoria yellow mottle virus, paprika mild mottle virus, etc. When the sequences of the viral coat proteins are compared, the tomato mosaic virus and the odontoglossum ringspot virus are the most closely related to TMV. Interestingly, cucumber green mild mottle virus is the most distantly related of the tobamoviruses to TMV. If the antibody has been tested for cross reactivity to many or all of the other tobamoviruses and shown not to cross react, then your results are pretty dependable. If not, then the test probably just identifying the presence of a tobamovirus. A third question to ask is, if they are using an antiserum, was the animal immunized with a purified viral protein or whole virus? Once again this goes to the specificity of the assay.

Hope this helps.

I don't know about the antibody or antisera but I asked for all viruses that they were scanning for, which included green mottle virus, tobacco, tomato mosaic viruses, pepino pepper mottle etc I can't recall all of them though.

Thanks so much for all the scientific info. I was/am pretty sure it is NOT fmv on my citrus. It looks very different and looks just like a bit of under nutrition. But I wanted to double check--thanks for clarifying it is not very plausible.