Extraction of viral double-stranded RNA from peach leaves infected with Apricot latent virus (ALV) followed by molecular cloning of synthesized cDNA and its sequencing, suggested that ALV is a new virus, whose coat protein (CP) coding region contains Apple stem pitting virus (ASPV)-related sequences. The sequenced portion of the ALV genome (1,444 nt) includes the putative CP gene and the 3' non-translated region. The 5' portion of this fragment (1-651 nt) is highly distinct whereas the 3' portion is 77% identical to the corresponding region of ASPV. Molecular hybridization experiments using a cRNA probe to ASPV with ALV-infected leaf tissue extracts also revealed that the genome of ALV contains nucleotide sequences related to that of ASPV. Western blots of tissue extracts indicated that ALV coat protein reacted with polyclonal antiserum against ASPV; however, the ALV CP differs in size from that of ASPV. ALV was graft-transmitted to several Prunus rootstocks. Based on the available sequence data, serological observations and bioassays we propose that ALV is a new species in the genus Foveavirus, typified by ASPV. ALV-specific PCR-primers and viral-specific cRNA probes developed in this investigation may be useful for detecting the virus and for studying its epidemiology and geographical distribution.
