Abstract
Mesophyll protoplasts isolated from plants of wheat, oat, maize (a local lesion host) and Japanese radish (normally a non-host) were efficiently infected with brome mosaic virus (BMV) without using poly-L-ornithine, and the optimum conditions for infection were very similar to those found using barley protoplasts. These results suggest that the host ranges of viruses can be extended by using protoplasts and that the conditions optimal for infection of protoplasts with BMV are determined mainly by the virus.