leaf forms in Wendy's Gold and Virus questions

[annew]

Trym and similar varieties are infected by virus. Trym has a strain of Cucumber Mosaic Virus and a Poty Virus. Trymlet and South Hayes are infected with CMV only. I am sure it is this strain of CMV which confers the outer petal markings to these varieties.  It seems that the virus may not be evenly distributed
throughout the bulb tissue, so that there may be sections of the bulb which have greatly reduced or no virus present in some chips, thus, a proportion of the progeny will "revert" to a non coloured outer petal.
No virus has been found in Wendys Gold, or in any ordinary yellow variety so far tested.

Oh, dear - that's rather alarming. I'd like to read up on that too, it sounds interesting.

[Brian Ellis]

Excellent information, thanks Rollo.  Richard Hobbs has always said that to me, but I haven't seen it in print before.

[RolloP]

There is nothing in print as such as this is something I have been doing for a few years with a virologist from the Central Science Laboratory at York ( now part of the Food and Environment Research Agency -FERA). Please see a letter I sent a few years ago.
             "  First, many thanks again, for your generosity in sending me the snowdrops Trym, Trymlet and South Hayes. They have settled in well and strong eager noses are appearing.

               As promised, I did send small leaf samples of each variety, together with Gerald Parker (which has leaf stripes ) and Clare Blakeway Phillips ( which is known to be virus infected, but flowers well ) of my own, to be assessed for any viruses at the Central Science Laboratory, near York .

                I must admit the results came as a bit of a surprise as I had expected your varieties to be clear ( they look healthy with no symptoms ) and my two varieties to have virus confirmed.

                However all 5 varieties are infected with Cucumber Mosaic Virus, and Gerald Parker, Clare B.P. and Trym are also infected with Potyviruses.  CSL did further work and sequenced the DNA of the potyviruses  found in Gerald Parker and Clare B.P. .

             Again the results were a surprise.  The virus in Gerald Parker was a previously undescribed , new to science, virus  (in the potyvirus complex), which has been given a proposed name of “Snowdrop Virus Y” (SnVY).
              The potyvirus in Clare Blakeway Phillips has been identified as “Ornithogalum Mosaic Virus “.
               Unfortunately the potyvirus in Trym could not be amplified for sequencing.

                              Where to begin ?
                 Potyviruses belong to a large family of viruses which includes PotatoVirusY which is damaging on Solanaceous plant crops e.g. Potatoes, Tobacco etc. It can sometimes be seen to good effect? on small Brugsmania (Datura) plants in Garden Centres.
                 There are many (100s) different strains, some mild, some severe, which have varying degrees of severity on the host plant.
                  Narcissus Leaf Stripe Virus and  Tulip Breaking Virus belongs to this group .
                 
                    Potyvirus transmission is mostly by aphids or other sap sucking insects                               (Nematode -Ditylenchus dipsaci- transmission is theoretically possible), by sap transmission, vegetative   propagation, e.g.twin scaling and natural division.

                    Potyviruses do not survive in dead leaves or other host debris. They do not survive long in vectors e.g. aphids or nematodes.
                    Transmission by true seed is possible  but not all strains are .
                     Interestingly, in recent years, wild collected Ornithogalum plants grown in Holland were showing virus symptoms and were found to be infected with OMV. The wild population they were taken from was tested and also found to be infected with the virus, showing this is a latent virus which only shows up when the plants are under stress.

                Cucumber Mosaic Virus.
                    CMV  has the widest host range of any virus in the world.
                     Many hundreds of strains exist, again some mild and some severe, some of which can cause colour break on the flowers of the host.
                      It is spread by many different aphid species and many common weeds e.g. Fat Hen can act as a reservoir.
                     Transmission is by sap (aphids) and vegetative propagation (natural division and twin scaling ). Some strains can be transmitted by true seed.
                      Again, I suspect that all the varieties tested may not be infected by the same strain of CMV.

                      So, as you can see, a virus is not just a virus. It is a classic case of  “ the more you learn, the more you realise how little you know “ !!

                      With modern diagnostic techniques for viruses, electron microscopes, DNA sequencing, ELISA etc, there is a lot of work going on and it seems to get more complex by the day !
                       It is dangerous to make an assumption of the basis of testing 5 varieties, but  I suspect there may be many more virus infected varieties that do not exhibit any symptom, than most people realise.                                                                 
                         Only by virus indexing  a major collection would we know for sure.     
                         Possibly only wild collected and true species may be free from virus.
                        There is a nice PhD  project for someone!

               What to do ?
                       Don’t panic!   
                       I suspect this has been with us for a long time. When you think how old many varieties are, e.g S.Arnott and Magnet,  and how many cycles of vegetative propagation they have been through, it is difficult to believe they are all totally virus free.
                      Twin scaling techniques must play a big part in possible virus transmission.
                      Scrupulous hygiene (to medical standards)  must be observed between varieties, and a batch of sterilant/fungicide must be used for one variety only, during twin scaling.
                      It may be beneficial to wash seed in a mild acid (acid extraction) and then soak the seed in a weak solution of bleach before sowing. This would lessen the possibility of transmission of  virus to the seedlings by virus particlesin the pulp adhering to the seed coat.
                      Extracts of Galanthus have good anti-viral properties and it may be that most strains of virus, esp. the mild strains, are suppressed, allowing infection but not showing any symptom and having little effect on the plant. Thus, as a genus, Galanthus have a good tolerance for virus infection.
                      Considering how badly herbaceous plants are affected by  Potyviruses and CMV,  Galanthus spp. and hybrids get off quite lightly.

                      More questions than answers I am afraid.

                      I think the best course of action is for growers to remove any plants showing obvious signs of severe virus, e.g. leaf stripes, observe basic hygiene principals in propagation work, enjoy what we have, and not worry too much about the issue, until someone has the opportunity, time, skill and knowledge to sort it all out !!

                   I hope this is of  interest to you.
 
           Regards,"

[mark smyth]

fascinating

Maybe your contact could sort out another problem. Does G. Cicely Hall = G. The Whopper

[Brian Ellis]

Most interesting Rollo, war is now waged on Fat Hen.

[ichristie]

Hello Rollo, fantastic information really interesting will read your notes over and over. I have several clumps of G plicatus Wendy's Gold in the garden looks like a fair mix of leaf types will post pictures, cheers Ian the Christie kind.

[ronm]

If any of my Iris or Crocus display signs of virus I have to date destroyed them!
Given that these viruses are everywhere, is this sensible or not?

[annew]

Fascinating - thanks so much for this information, Rollo.
Ron, good question. I've just been round my greenhouses yesterday and taken out every pot of bulbs showing even a slight trace of leaf mottling or stripe. I wonder how many others are harbouring it without symptoms. Should we worry? I do have a lot of spare space in my plunges now!
I hope to keep my seedlings clear, though.

[ronm]

Seems like some hate the effects of the virus and some value it immensely. 
Personally I try through non 'anti environmental' means to eradicate all pests ( whether foreign or domestic !!) but suspect when it comes to sub microscopic organisms I am fighting a losing battle. Especially when my next door neighbour may be propagating an infected plant, ( and profiting from its mass multiplication/ global marketing!). I burn all CMV infected plants. 

[Martin Baxendale]

Hello Rollo, fantastic information really interesting will read your notes over and over. I have several clumps of G plicatus Wendy's Gold in the garden looks like a fair mix of leaf types will post pictures, cheers Ian the Christie kind.

Ian, in your pics, Wendy's Gold 3 group looks like Primrose Warburg or Spindlestone Surprise, so you don't have quite as much leaf variation as you thought  

[mark smyth]

Very observant Martin. I was concentrating on the leaves ad didnt notice

[ichristie]

Well I never, I have had this group for quite a while and must now compare it with the other Primrose Warburg don't think it is Spindlestone surprise will have a look at those as well thank you both for keeping me right, cheers Ian the Christie kind.

[ichristie]

Hello again, I went down to look at G Wendy's gold 3 this morning and found a label under the clump which read G Primrose Warburg should always check sorry for confusion, cheers Ian the Christie kind.

[Alan_b]

Rollo, it seems to me that you have proven that Trym, Trymlet, South Hayes, Gerald Parker and Claire Blakeway Philips are all infected by Cucumber Mosaic Virus, at least insofar as this pertains to the examples tested.  But I cannot follow how you make a link between the virus and the "inverse poculiform" character of the first three.  Jo Hynes has a snowdrop called "Wind Turbine" which produces two scapes per bulb.  The first scape has makings similar to South Hayes but the second scape generally does not.  I cannot see how this behaviour would fit with a virus theory.       

[RolloP]

Alan,
    The description of "Wind Turbine" is unusual and intriguing. As mentioned in a previous post,it would seem that the Cucumber Mosaic Virus in these "inverse poculiform" varieties may not be evenly distributed
throughout the bulb. This is evidenced by the production, after micro-chipping, of "reverted" types on a percentage of the progeny. The comments in another topic (Snowdrops in February2012 pg.39 reply574)
regarding "White Hayes" would seem to bear this out. "White Hayes" has CMV present, but not in sufficient quantities to produce a symptom. The "inverse poculiform" will not be seen until the virus has built up enough to show the effect. Virus symptoms usually appear when the plant is under stress for whatever reason. This will vary between varieties and species.
   Galanthus, as a genus, has very strong anti viral properties and extracts have been used against both human and animal viruses. I don't know if these substances kill the virus in the plant or suppress them, but as in most plants the symptom expression is directly related to the amount of virus present. Thus a plant that is growing well can keep ahead of the virus and show no symptom but when growing slowly under stress the virus can multiply more quickly and show an effect. In the case of "White Hayes", I would expect a plant in good growing conditions to remain "normal", whereas a plant growing in less than optimal condition to assume the "inverse poculiform" markings sooner.
  I have spent a working lifetime chasing and dealing with new and exotic pests and diseases of plants. The one thing they have in common is that none have read the same books as the so-called experts.
 Snowdrop viruses are no different. The result being is that often the unexpected/unexplained occurs when conventional wisdom says it should not happen.
    Back to "Wind Turbine", I would suspect this variety has a strain of CMV. If I am correct in thinking the virus is  not evenly distributed within a bulb,this is exactly what I would expect.The second scape may be from a part of the bulb with fewer virus particles. I would predict that the second scape will show "reverse poculiform" characteristics in the future.
  Virtually nothing is known or understood about the viruses and symptom expression in Snowdrops. I suppose this is because it is not a commercial crop as Narcissus are.
 Nothing seems to make sense.
 "Augustus" - big textured flowers - potyvirus, Narcissus Late Season Yellow Virus present.
 "Melanie Broughton " - big textured flowers - Virus present - not yet identified.
 "S.Arnott" - NLSYV + CMV present - no symptoms, grows and flowers well.
 " Diggory" - big textured flowers - no virus present.
  "Comet" - green tips (sometimes) on outer petals - CMV present.
 "Janquenetta" - green tips on outer petals - CMV present.
  "Godfrey Owen" - extra outer petals - CMV present.
  " Peter Gatehouse" - streaky green mark on inner petals - CMV present.
  " Modern Art" - streaky green on outer petals - Potyvirus present, not yet identified.
  " Magnet " - no virus present.
  Test kits for CMV are available from  www.pocketdiagnostic.com/products/20
 They cost £20.10+vat per 4 kits. Given that CMV appears to be the most prevalent virus, some people may think it worthwhile to try the test kits.
  I suspect the CMV strain in the "Trym" type varieties is not the same strain as in other CMV infected varieties.
 I also suspect that the green tips and or stripes on outer petals are caused by virus.



 
(edit by maggi to repair web link)