VIEW ARTICLE

Inhibition of the Multiplication of Bromegrass Mosaic Virus in Barley by the Antibiotic Blasticidin S. J. Kummert, Laboratoire de Pathologie végétale, Faculté des Sciences agronomiques, 5800 Gembloux, Belgium; J. Semal, Laboratoire de Pathologie végétale, Faculté des Sciences agronomiques, 5800 Gembloux, Belgium. Phytopathology 61:10-14. Accepted for publication 3 July 1970. DOI: 10.1094/Phyto-61-10.

The effect of blasticidin S (BcS) on the multiplication of bromegrass mosaic virus (BMV) in barley was investigated. Virus synthesis was evaluated (i) by spectrophotometric measurement of the virus content of the leaves; (ii) by measuring the virus-induced RNA polymerase activity (VPA) in cell-free leaf extracts, as assayed by incorporation of tritiated uridine-5’-triphosphate (UTP-³H) in the presence of actinomycin D. The action of BcS on virus-induced pathological effects was also investigated. Virus synthesis was inhibited in leaf 1, or delayed in leaf 2, when BcS was applied to one-leaf seedlings at 3 hr after inoculation with BMV; this was correlated with a similar inhibition or delay of VPA as measured in leaf extracts prepared from BcS-treated infected plants, together with a reduction of pathogenic effect. BcS added in vitro to the UTP-³H-incorporating system had no effect. It is concluded (i) that BcS acts at an early phase of infection, presumably at the level of the virus-induced RNA polymerase system; and (ii) that VPA, as measured in vitro, reflects a functional step which is a prerequisite for the in vivo synthesis of BMV.