Alterations in the soluble protein patterns of tobacco and cowpea leaves following inoculation with tobacco necrosis virus

Changes in the soluble protein composition of both tobacco and cowpea leaves following inoculation with tobacco necrosis virus (TNV R/1 : 1.5/19 : S/S : S/Fu [1]) have been investigated by the techniques of disc-electrophoresis. Both changes in relative amounts of proteins, and novel proteins have been observed. Changes in the protein constitution of soluble extracts were observed by densitometer tracings of polyacrylamide gels, and have been shown to be different for the two host plants, with other differences found by acid or alkaline extraction of protein. Acidic extraction of soluble protein appeared to be preferential for the new proteins found in infected leaves. In cowpea leaves the stimulation of new proteins seems to be related to symptom severity, with larger amounts found in necroticised tissue. The possible function of these proteins, and their rôle in induced resistance studies is discussed