Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2008
Publication Date: 3/27/2008
Citation: Li, R., Mock, R.G. 2008. Characterization of a flowering cherry strain of cherry necrotic rusty motttle virus. Archives of Virology 153(5):973-978. usty. Archives of Virology.
Interpretive Summary: Plant viruses, including Cherry necrotic rusty mottle virus (CNRMV), a virus with many unidentified characteristics, pose a serious threat to the production of fruiting and flowering varieties of stone fruits (almonds, apricots, cherries, nectarines, peaches, and plums). Global movement of infected stone fruit plants can contribute to virus outbreaks throughout the world. Therefore, the development of accurate and rapid virus detection tests is important to prevent the introduction and spread of viral diseases. The newly named and characterized Flowering Cherry strain of CNRMV (CNRMV-FC) was first detected by our unit in a new natural host, flowering cherry plants imported from Japan, during a routine quarantine virus test in 2003. The viruses that infected two of the imported trees were selected for further study. Tests were performed by grafting infected CNRMV-FC wood chips to a wide variety of stone fruit plants and infectivity and symptom expression were measured (host range study). The virus was also cloned and its genetic organization was determined. We compared the infectivity and symptoms of the host range and the genetic information of the CNRMV-FC with isolates of CNRMV found in Washington state and in Europe and have determined the CNRMV-FC isolates are significantly different from other known isolates of CNRMV. The genetic information gathered from this study was used to develop a molecular-based test (RT-PCR) for the detection of CNRMV and Cherry green ring mottle virus in the USDA plant quarantine program and is useful as a tool to help scientists further understand and define the characteristics of this unassigned virus.
Technical Abstract: The host range and complete nucleotide sequences of two Cherry necrotic rusty mottle virus (CNRMV) isolates (FC4 and FC5) infecting flowering cherry accessions imported from Japan are described. Of the plants tested, sweet cherry cvs. ‘Bing’, ‘Canindex’, ‘Mazzard’ and ‘Sam’, flowering cherry cv. ‘Kwanzan’, peach cvs. ‘GF 305’, ‘Boone County’ and ‘Lovell’, apricot cv. ‘Tilton’ and almond cv. ‘Peerless’ became infected, but only Canindex and Tilton showed a mild foliar mottle. Unlike previously reported CNRMV isolates, CNRMV-FC did not induce any symptoms on the woody indicator, Sam. The genomic sequences of CNRMV-FC4 and CNRMV-FC5 are 8,430 nt and 8,429 nt in length, excluding the 3’ poly (A) tail. They contain seven open reading frames encoding for a putative virus replicase (ORF1), “triple gene block” proteins (ORFs 2, 3 and 4), a coat protein (ORF5) and two proteins with unknown functions (ORFs 2a and 5a). The two CNRMV-FC isolates share 96% identity in the genomic sequences, and their genome organizations are virtually identical to that of a CNRMV German isolate (CNRMV-GER). However, they differ from CNRMV-GER by 14% in the overall nucleotide sequence and 2% (ORF2) to 30% (ORF5a) at the derived amino acid sequences of individual gene product.