A kinetic study of local lesion growth on Nicotiana glutinosa resulting from tobacco mosaic virus infection

The spread of local lesions produced by three different strains of tobacco mosaic virus was measured as a function of time. Although each virus strain had its own characteristic spreading rate, the three rates were uniform with time. A direct proportionality was observed between lesion area and extractable infectious material associated with strains U1 and U2. Strain U8 appeared to show a decrease in infectivity associated with larger lesion areas or increased age of necrosis. These kinetic studies have led to the conclusion that the processes involved in secondary infection are highly efficient ones, and that the intercellular invading unit need not be identical to the in vitro TMV rod.