Ribonucleic acids produced in tobacco leaves during the course of tobacco mosaic virus infection

The nucleic acids in TMV-infected tobacco leaves were analyzed mainly by MAK column to make clear the mode of virus multiplication in the host. The nucleic acids of tobacco leaf-disks infected for 5 days with TMV contained an unusual RNA that was resistant to RNase of 0.5μg/ml and had TMV-RNA type base ratio. This fraction was eluted near DNA peak on MAK column. The rate of P32 incorporation into 18s ribosomal RNA from infected leaf-disks decreased as compared with that into the same RNA from uninfected leaf-disks. Treatment of uninfected leaf-disks with MC markedly reduced the rate of P32 incorporation into all the RNA fractions, whereas, in infected leaf-disks, the same incorporation into 28s RNA which contains TMV-RNA was not affected by MC treatment.From these results, the mode of TMV multiplication in tobacco leaves at the early infection stage is discussed.