[show abstract][hide abstract] ABSTRACT: A reverse transcription-polymerase chain reaction (RT-PCR) procedure was developed to detect Amasya cherry disease (ACD) in naturally infected sweet cherry (Prunus avium) leaves sampled from Turkey. The procedure was based on detection of the presence of a mycoviral-like double-stranded RNA (dsRNA) of 5·3 kbp always found in association with ACD, which is probably caused by a fungus. Specific primers were designed to amplify a fragment of the diagnostic dsRNA. The method will improve routine diagnosis of ACD in Prunus spp.
[show abstract][hide abstract] ABSTRACT: The sequence of the four large (L) double-stranded RNAs (dsRNAs) associated with Amasya cherry disease (ACD), which has a presumed fungal aetiology, is reported. ACD L dsRNAs 1 (5121 bp) and 2 (5047 bp) potentially encode proteins of 1628 and 1620 aa, respectively, that are 37% identical and of unknown function. ACD L dsRNAs 3 (4458 bp) and 4 (4303 bp) potentially encode proteins that are 68% identical and contain the eight motifs conserved in RNA-dependent RNA polymerases (RdRp) of dsRNA mycoviruses, having highest similarity with those of members of the family Totiviridae. Both terminal regions share extensive conservation in all four RNAs, suggesting a functional relationship between them. As ACD L dsRNAs 1 and 2 do not encode RdRps, both are probably replicated by those from either ACD L dsRNA 3 or 4. Partial characterization of the equivalent L dsRNAs 3 and 4 associated with cherry chlorotic rusty spot revealed essentially identical sequences.
Journal of General Virology 11/2006; 87(Pt 10):3113-7. · 3.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: Cherry chlorotic rusty spot (CCRS) and Amasya cherry disease (ACD) display similar symptoms and are associated with a series of dsRNAs. However, a direct comparison has been lacking. Here, a side-by-side analysis confirmed that both diseases were symptomatologically very similar, as were the number (10-12) and size of their associated dsRNAs. Sequence determination of four of these dsRNAs revealed that they were essentially identical for CCRS and ACD. The largest (3399 bp), which potentially encoded a protein of 1087 aa with the eight motifs conserved in RNA-dependent RNA polymerases of dsRNA mycoviruses, had the highest similarity to those coded by dsRNA 1 of viruses belonging to the genus Chrysovirus and was termed CCRS or ACD chrys-dsRNA 1. The three closely migrating dsRNAs had the properties of the other components of a chrysovirus and in CCRS and ACD versions, respectively, were chrys-dsRNA 2 (3125 and 3128 bp), chrys-dsRNA 3 (2833 bp) and chrys-dsRNA 4 (2499 and 2498 bp), potentially encoding the major capsid protein (993 and 994 aa) and two proteins (884 and 677 aa, respectively) of unknown function. The four 5'- and 3'-UTRs shared internal similarities and had conserved GAAAAUUAUGG and AUAUGC termini, respectively. The 5'-UTRs contained the 'Box 1' motif followed by a stretch rich in CAA, CAAA and CAAAA repeats, characteristic of chrysovirus dsRNAs. Because species of the genus Chrysovirus have only been described as infecting fungi, this suggests a fungal aetiology for CCRS and ACD, a proposal supported by the properties of two other CCRS- and ACD-associated dsRNAs (see accompanying paper by Coutts et al., 2004, in this issue).
Journal of General Virology 12/2004; 85(Pt 11):3389-97. · 3.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: Two dsRNAs from cherry trees affected with cherry chlorotic rusty spot (CCRS) in Italy and Amasya cherry disease (ACD) in Turkey were sequenced and found to be essentially identical. The larger dsRNA 1 (2021 or 2006 bp, respectively) potentially encoded a protein of 621 aa containing the conserved motifs of the RNA-dependent RNA polymerases (RdRp) of dsRNA mycoviruses, having highest similarity with those in the genus Partitivirus. The smaller dsRNA 2 (1841 or 1839 bp, respectively) had properties consistent with the second genomic component of a partitivirus and potentially encoded the coat protein (CP) of 504 aa. Phylogenetic analysis based on the RdRp and CP was coincidental and indicated that species in the genus Partitivirus could be separated into two subgroups. Because species of this genus only infect fungi, these observations suggest a fungal aetiology for CCRS and ACD, further substantiating a previous proposal (see accompanying paper by Covelli et al., 2004, in this issue).
Journal of General Virology 12/2004; 85(Pt 11):3399-403. · 3.13 Impact Factor