Characterization of two different apricot latent virus variants associated with peach asteroid spot and peach sooty ringspot diseases

International audience; Peach asteroid spot (PAS) and peach sooty ringspot (PSRS) are two diseases of stone fruit trees of unknown aetiology. The use of a cRNA probe of the newly described Apricot latent virus (ApLV), a tentative member of the Foveavirus genus, indicated the presence of cross-hybridizing agents in PAS isolate LA2 and in PSRS isolates Caserta 12 and Clava J4. Analysis of dsRNA patterns revealed in each case the presence of a major dsRNA band of about 9.6 kbp. The purified dsRNAs were used to obtain cDNA clones for isolates LA2 and Caserta 12. Sequence analysis of a 1.1 kbp cDNA clone from isolate LA2 showed very high homology with the known ApLV sequence, indicating that this isolate represents a closely related variant of ApLV. Sequence analysis of a 3.06 kbp Caserta 12 cDNA clone representing the 3′ region of the genome revealed a genomic organization similar to that reported for other members of the Foveavirus genus, including the triple gene block and a large, 43.6 kDa coat protein. Sequence comparison with the CP gene of ApLV, the only sequenced region so far for this virus, showed an overall homology of 78%. These results indicate that the foveavirus represented by the Caserta 12 isolate of PSRS disease may be regarded as a distant variant of ApLV. The present results indicate that the viral agents associated with peach asteroid spot and peach sooty ringspot diseases might be variants of the recently described ApLV.