Detection and partial characterization of two distinct walnut isolates of cherry leaf roll virus (CLRV)

Two new cherry leaf roll virus (CLRV) isolates (Ah and Ad) were isolated and detected from traditionally-grown walnuts that showed severe apical necrosis and chlorotic spots in systemically infected Cheneopodium amaranticolor, in the eastern part of Turkey. The 404 and 405 bp long DNA fragments of the 3'-non-coding region of both isolates from PCR reactions were cloned and sequenced. A significant genetic variability (up to 14% divergence between sequences) was found within the 3' terminal region of viral genome of CLRV Turkish isolates compared with the isolates in databases. The sequence of Ad isolate was found to share 84 to 98% and the Ah isolate was found to share 85 to 97% nucleotide identity with corresponding sequences of the selected world isolates. An RNA riboprobe generated for CLRV-Ad isolate reacted also with the CLRV-Ah isolate in dot blot molecular hybridization test. Positive reactions were still visible in hybridization test when the extracts of infected fresh and dried leaf tissues of C. amaranticolor diluted 1:20. Western blot analysis revealed that the molecular mass of the coat protein of about 52 kDa for both isolates.