Southern bean mosaic virus RNA remains associated with swollen virions during translation in wheat germ cell-free extracts.

L-[35S]Methionine-labeled translation complexes were prepared by incubating either swollen intact southern bean mosaic virus (SBMV) particles or unencapsidated SBMV RNA in a wheat germ extract. The complexes were analysed by sucrose gradient centrifugation and by electron microscopy and dot blot hybridization of fractions from these gradients. In these complexes, 80 S ribosomes appeared to be associated with intact or near intact particles, suggesting that SBMV particles disassemble only after their RNA has initiated translation. This is in contrast to some other isometric viruses, such as turnip yellow mosaic virus, which appear to release their RNA rapidly prior to translation.