Identification of the Rose Rosette Disease Agent

Rose rosette disease (RRD) was first described in the 1930s. Symptoms of RRD include mosaic and mottling patterns on leaves, reddening on newly emerging shoots, excessive thorniness on stems, and witches’ broom. A new Emaravirus, Rose rosette virus (RRV) was characterized and found in perfect association with RRD. Molecular detection methods including RT-PCR and qRT-PCR as well as immunological tests have been developed to aid screening roses for RRV. Past research has established that RRD is spread by the eriophyid mite Phylocoptes fructiphilius and we were able to detect RRV in mites.  Mites were individually collected from RRV-positive roses and transferred to RRV-free roses. Two months post infestation, material was tested positive for RRV. The typical symptoms of RRD, described above later developed. Total nucleic acids from  diseased plants was subjected to deep sequencing and no other viruses were detected in diseased roses proving that RRV causes RRD.