Field Resistance to Rose Rosette Disease as Determined by Multi-Year Evaluations in Tennessee and Delaware

Abstract

Rose rosette disease (RRD) caused by the rose rosette emaravirus (RRV) and transmitted by the eriophyid mite Phyllocoptes fructiphilus (Pf), both native to North America, has caused significant damage to roses over the last several decades. As cultural and chemical control of this disease is difficult and expensive, a field trial was established to systematically screen rose germplasm for potential sources of resistance. One hundred and eight rose accessions representing the diversity of rose germplasm were planted in Tennessee and Delaware, managed to encourage disease development, and evaluated for symptom development and viral presence for three years. All major commercial rose cultivars were susceptible to this viral disease to varying levels. The rose accessions with no or few symptoms were species accessions from the sections Cinnamomeae, Carolinae, Bracteatae, and Systylae or hybrids with these. Among these, some were asymptomatic; they displayed no symptoms but were infected by the virus. Their potential depends on their ability to serve as a source of viruses. The next step is to understand the mechanism of resistance and genetic control of the various sources of resistance identified.

Quantification of rose rosette emaravirus (RRV) titers in eriophyoid mites: insights into viral dynamics and vector competency

“…The negative-sense, single-stranded RNA (-ssRNA) genus Emaravirus (family Fimoviridae ; order Bunyavirales ) is an emerging group of eriophyoid-transmitted viruses comprising more than 30 classified and putative species with worldwide distribution and economic impact [2,11]. Emaravirus rosae (member: rose rosette emaravirus, RRV) is considered one of the most economically significant emaraviruses, as infected plants die within two to five years after the onset of symptoms [5], affecting the profitability and sustainability of commercial operations and landscapers in the United States [7,12].…”

Genetic Diversity among Rose Rosette Virus Isolates: A Roadmap towards Studies of Gene Function and Pathogenicity

“…For example, tea roses are themselves hybrids: the floribunda rose bush is a cross between the hybrid tea rose and the polyantha rose. Windham et al (2023), in this special issue of Pathogens [27], explain that the major commercial rose cultivars are bred from genetically diverse North American, European, and Asian species or hybrids derived from several Rosa taxonomic sections [28][29][30]. Since most commercial varieties are susceptible to rose rosette disease (RRD), breeders are performing replicated trials to identify new genetic sources of RRV resistance, and this requires using a consistent inoculum and introducing good disease pressure to produce symptoms in young rose plants [28,31,32].…”