Homologies between the genomes of a carlavirus (lily symptomless virus) and a potexvirus (lily virus X) from lily plants

Abstract

cDNA clones complementary to the 3'-terminal regions of the genomic RNAs of the carlavirus lily symptomless virus and the potexvirus lily virus X (LVX) have been sequenced. The carlavirus RNA sequence contains five open reading frames (ORFs) coding for proteins of Mr 25,374, 11,631, 6960, 32,041 (coat protein) and 16,121, which are all very similar in size, amino acid sequence and relative position in the genome to proteins encoded by two different potato carlaviruses. The first four of these proteins also show considerable amino acid sequence similarity to proteins encoded by RNA of potexviruses, and the relative position of the ORFs on the carlavirus genome strongly resembles that in the potexvirus genomes. The LVX cDNA clone contains three ORFs encoding proteins of Mr 23,574, 11,767 and 21,569 (coat protein). A small ORF immediately 5' of the coat protein ORF, which has been found in other potexvirus genomes, is not present in the LVX genome. Thus, the data confirm the close taxonomic relationship between carlaviruses and potexviruses and reveal some differences in genome organization among the potexviruses.