SUMMARYThe nucleotide sequences of cDNA clones corresponding to RNA-3 and RNA-4 of beet necrotic yellow vein virus isolates F2 and G l have been determined. The cDNA of RNA-3 of isolate F2 is 1775 residues in length and contains a coding region of 219 codons. In isolate G1 this coding region has undergone an internal deletion of 354 nucleotides in such a way as to conserve a shortened reading frame. Otherwise, the RNA-3 sequences of the two isolates were closely similar. RNA-4 of isolate F2 has an extrapolated length of 1431 residues and contains an open reading frame of 282 codons. This open reading frame has undergone an internal deletion of 324 nucleotides in one cDNA clone of RNA-4(G 1) with conservation of a shortened reading flame. Sequence analysis of other RNA-4(G1) cDNA clones revealed, however, that the exact boundaries of the deletion are not always the same. RNA-3 and RNA-4 of each isolate are more than 90 % homologous for the Y-terminal 200 nucleotides. Short homologous sequences are also present in RNA-3 and RNA-4 of isolate F2 flanking the regions deleted in each of these RNAs in the G 1 isolate. These homologous sequences probably play a role in the deletion process.

SUMMARYThe complete nucleotide sequence of beet necrotic yellow vein virus (BNYVV) RNA-2 has been determined from a study of cloned cDNA. The RNA sequence is 4612 nucleotides in length, excluding the poly(A) tail. There are six long open reading frames (ORFs) in the sequence. The viral coat protein cistron is the ORF nearest to the 5' terminus and the coat protein amber termination codon is followed by a long in-phase

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