Abstract
RNA from particles of isolate H of strawberry latent ringspot virus (SLRV) comprises species of mol. wt. 2.9 x 106 (RNA-1), 1.4 x 106 (RNA-2) and 0.4 x 106 (RNA-3). Isolates obtained by inoculating plants with RNA-1 plus RNA-2 lacked RNA-3, even after repeated subculturing. RNA-3 was produced when it was inoculated in mixtures with the RNA of such isolates, but not when it was inoculated alone. Most of the nucleotide sequence of RNA-3 was absent from either RNA-1 or RNA-2. RNA-3 is therefore a satellite RNA. SLRV isolates containing or lacking satellite RNA induced indistinguishable symptoms in test plants. Like the genome RNA of SLRV, satellite RNA was found to be polyadenylated and to be bound covalently to protein. Satellite RNA induced the synthesis of a 38000 mol. wt. polypeptide in rabbit reticulocyte lysates. Several properties of SLRV satellite RNA therefore resemble those of tomato black ring virus satellite RNA.