The genome-linked protein of potato leafroll virus is located downstream of the putative protease domain of the ORF1 product.

The sequence of the 32 N-terminal amino acids of the protein (VPg) which is covalently linked to the RNA of potato leafroll virus has been determined. The obtained VPg sequence mapped to position 400 to 431 of the PLRV ORF1 product, downstream of the putative protease domain and in front of the RNA-dependent RNA polymerase. Comparison with other viral sequences revealed significant similarities with the ORF1 products of beet western yellows virus, cucurbit aphid-borne yellows virus, and beet mild yellowing virus.