Abstract
Local lesions induced by an ordinary strain of tobacco mosaic virus (TMV-OM) appeared 8-12hr earlier than those by a bean strain of tobacco mosaic virus (TMV-B) both on Nicotiana glutinosa and on Nicotiana tabacum ‘Xanthi nc’. This was supported by the multiplication curves of the two strains. No difference was found in the time of local lesion appearance between intact TMV and its RNA for both the TMV-OM and TMV-B. When the inoculated plants which had been incubated at 32C for 2 or 3 days were transferred to 25C or when the inoculated leaves were treated with actinomycin D at 32C, local lesion by TMV-OM appeared 4.9-5.5hr earlier than those by TMV-B. These results suggest that the local lesion formation is composed of two distinct phases, a phase of virus multiplication and that of tissue degeneration, and that processes of these phases are both affected strongly by the genetic nature of the strains.
