THE COMPLETE SEQUENCE OF THE GENOMIC RNAS OF SPINACH LATENT VIRUS

We describe the sequence for the complete genome of spinach latent vir us (SpLV). Comparisons of this genome with that of the only other comp lete genome described for a species within the genus Ilarvirus (citrus leaf rugose virus - CiLRV) indicate that while there are marked diffe rences between the RNA 3 of the two viruses, their respective RNAs 1 a nd 2 share many similarities. However, the putative 2a protein of SpLV contains a C2H2 type ''zinc finger''-like motif located towards the c arboxy terminal of the protein which is absent in CiLRV and has not be en reported for other members of the family Bromoviridae. A second ope n reading frame (2b), located at a similar position to that described for the cucumoviruses, occurs in the RNA 2 of both SpLV and CiLRV. The putative coat protein of SpLV is similar to that of citrus variegatio n virus (CVV) and asparagus virus 2 (AV-2), both members of subgroup 2 of the ilarviruses, We have subsequently demonstrated a serological r elationship between SpLV and other viruses in subgroup 2 and suggest t hat SpLV should be included in this subgroup rather than remain in a s eparate group (subgroup 6). However, while the putative movement prote in of SpLV is remarkably similar to that of AV-2, it shows little rela tionship with the corresponding protein of CVV and the lack of similar ity suggests that a recombination event may have occurred in the past. The relationship between the genera Alfamovirus and Ilarvirus is disc ussed in the light of the data for the genome of SpLV and recently pub lished information for other members of the genus Ilarvirus.