Studies on the formation of tobacco mosaic virus ribonucleic acid. 8. Fate of parental viral RNA in the host cell.

Fate of parental viral RNA in the host cell was determined with the use of P(32)-labeled tobacco mosaic virus (TMV)-RNA as inoculum. There was a wide variation in the retention of TMV-RNA that was rubbed on the tobacco leaf surface. On the average, about 0.73 mug of viral RNA was retained by tobacco leaf. About 63 per cent of the retained RNA was degraded in the leaf cells. On the average, about 0.27 mug of TMV-RNA was conserved in a tobacco leaf. The conserved parental TMV-RNA was remarkably stable and was located in the nuclear fraction of leaf homogenate. It could be isolated in an undegraded form and was RNase-sensitive, presumably single-stranded. About 2 per cent of it was associated with progeny TMV.