last revised 1-28-2020
By Henry Kuska
retired, Associate Professor, Department of Chemistry, University of Akron
Ph.D., Physical Chemistry
"This page gives the information that I have collected from my own literature searches and from others posting on the internet. Please let me know if you feel anything is not clear or is not addressed at all as I am continually updating/modifying it as I get feedback." The bold face was added by me for emphasis (H.Kuska).
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In a 2015 research paper, He et al. applied deep sequencing to determine that a rose multiflora sample was infected by a new virus which they provisionally named Rose Leaf Rosette Associated Virus of the genus Closterovirus, family Closteroviridae. They tested 20 samples that exhibited the symptoms. 12 of these tested positive for the virus. They did not answer the question of what caused the symptoms in the 8 remaining symptomatic samples.
Apparently they did not test for the virus that gives some similar symptoms - rose rosette virus. The following is their discussion of why they dismissed the possibility that they are observing rose rosette virus:
"Recently, a severe virus-like disease, characterized by a leaf rosette or witches’ broom symptom formed by dense small leaves on branches, was observed in China. The accompanying symptoms included remarkable decline, dieback and, eventually, plant death several years later. Here, we designate this disease as ‘wild rose leaf rosette disease’ (WRLRD). It is similar to the previously reported rose rosette disease (RRD), which is regarded as a serious problem by the nursery industry and many home gardeners, because it is lethal to the wild rose and potentially lethal to many ornamental rose species and cultivars. RRD is caused by Rose rosette virus (RRV) (Laney et al., 2011).WRLRD differs from RRD in the following ways: first, the witches’ broom symptom consists of the proliferation of only small leaves along the canes, instead of both leaves and twigs at the ends of canes; second, the leaves are not distorted and twisted; third, the thorns are not red-tinged or produced in excess."
http://agris.fao.org/agris-search/search.do?recordID=US201500194418
In a later paper He et al. reported that this virus has also been found in another R. multiflora sample showing rosette leaf. This sample was subjected to RT-PCR identification of the other three viruses associated with the symptoms in the first paper (He et al., 2015). It was also co-infected by Apple stem grooving virus and Blackberry chlorotic ringspot virus, but absent of Prunus necrotic ringspot virus. They then state: "thus showing that the etiology responsible for the symptoms needs further clarification."
http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-12-15-1468-PDN
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Another paper that used high through sequencing to look at Rosa chinensis Jacq. found PNRSV, rose spring dwarf, and rose leaf rosette-associated virus.
https://link.springer.com/article/10.1007/s00705-020-04739-8
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The rose leaf rosette-associated virus has now been found in California:
https://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-10-20-2268-PDN
My other rose virus sites can be reached from the following index page: