ISHS Acta Horticulturae 657: XIX International Symposium on Virus and Virus-like Diseases of Temperate Fruit Crops - Fruit Tree Diseases
MOLECULAR CHARACTERIZATION OF A NEW FOVEAVIRUS IN PRUNUS ACCESSIONS OF ASIAN ORIGIN |
| Authors: | A. Marais, L. Svanella-Dumas, X. Foissac, T. Candresse |
| Keywords: | Filamentous virus, aetiology, Foveaviruses, double-stranded RNA |
| Abstract:
The presence of a viral agent cross-reacting with Plum pox virus antiserum in Prunus accessions of mostly Asian origin has been previously reported. These “Prunus latent virus” (PLV) were screened using a polyvalent nested-PCR test allowing the detection of members of three viral genera, Capillo-, Fovea-, and Trichovirus. The sequencing of the amplified fragments allowed the identification of a previously uncharacterized virus belonging to the Foveavirus genus. Using purified double-stranded RNAs associated with the infected plants and a variety of PCR cloning strategies, further sequence characterization of this new agent was achieved. This approach allowed the determination of the sequence of the 3’ half of the viral genome and of a small fragment in the 5’ half region. The genomic organization and sequence comparisons with other filamentous viruses confirmed that this new viral agent is a Foveavirus. The new virus shows, however, a distinctly long 3' non-coding region of 845 nucleotides, a feature so far unique among known Foveaviruses. The coat protein shows 22.7% amino acid sequence identity with that of the Foveavirus genus type member, Apple stem pitting virus. The failure of a PPV antiserum to immunoprecipitate the in-vitro synthetized coat protein of the new virus suggested that this agent is not the PLV. The 3’ non-coding region and the coat protein gene sequences were also determined for another strain of this new Foveavirus. The two isolates shared only 61% amino acids of identity in their capsid. From the available sequence information, two pairs of detection primers were designed to evaluate the presence of this new Foveavirus in other Prunus accessions known to be infected by PLV. Preliminary results show that the new virus was detected by the two PCR assays in only six out of the eight accessions tested, confirming that PLV could be distinct from the newly characterized Foveavirus. Studies are in progress to evaluate the prevalence of this agent in Prunus germplasm. | |
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