New virus paper - New Zealand

“The samples were tested by RT-PCR for 17 viruses known to infect roses. Of the 89 samples tested, 48 % were infected with Rose cryptic virus-1, 22 % with Prunus necrotic ringspot virus, 20 % with Rose spring dwarf-associated virus, 10 % with Rose yellow vein virus, 2 % with Arabis mosaic virus and 35 % of the samples tested negative. The viruses were detected in some samples as single infections and sometimes as mixed infections (2 or 3 viruses together). Viruses were detected in all regions sampled in both the North and South Islands of New Zealand. Rose cryptic virus-1 and Rose spring dwarf associated virus were detected for the first time in New Zealand and Rose yellow vein virus, which had only been recently detected in 2011, was found to be widespread.”

As little as 35% testing negative…

Are there comparable studies out of New Zealand?

Hi Henry

Is it possible to read the full report? I would be very interested to learn more about this.

There are relatively few rose nurseries here and many are working to diminish virus issues so it would be nice to know where the samples were obtained and from which cultivars.

Mike

The Rose yellow vein virus is the one that we recently published the sequence of Complete nucleotide sequence of rose yellow vein virus, a member of the family Caulimoviridae having a novel genome organization - PubMed Dimitre and Ben shared the primers with this group and we worked together in the order of these papers coming out.

There are a lot of rose viruses out there and more still being characterized. The cryptic viruses generally have a minor effect (not always). Crytic viruses as a group tend to be seed transmitted to and that is likely how they have become widespread. There are lots of examples of different cryptic viruses in other species and they are not generally 100% seed transmitted. There is more work people can do to characterize which key rose parents used routinely by breeders test positive and what is the rate of transmission. Maybe there are things we can do to reduce transmission environmentally or culturally.

I think over time we will end up considering which viruses we should be more concerned about controlling and which have minor symptoms and are widespread enough that we learn to tolerate them.

This is a great survey study to highlight that the best we can do is have virus indexed roses. This means that roses are tested for particular viruses and hopefully found to be negative for them. There are other viruses out there and viruses that are difficult to see with electron microscopy at times of the year, etc. Saying ones roses are virus-free roses is a red flag. Nurseries that claim this suggest they don’t understand what virus-free versus indexed means and ultimately it is a big claim that is hard to support. Good thing UC Davis and Malcolm Manners and others are working to generate roses that are clean of known and problematic viruses for the industry to use for propagation.

Mike, I often can get the full paper free through my university, but so far it has not become available. Possibly if you e-mail one of the authors, they will send you a free “reprint” (at least that used to be the custom - I retired in 1993).

The abstract may be misleading on one aspect. The tested roses were not selected at random. The full paper states:

"The majority of samples were symptomatic, however, a few had no symptoms.

I’m glad to see that, otherwise something has gone haywire. It’s bad enough with the rise of fungus.

.

Neil