Abstract:
Bioassay results confirmed the role of low
molecular weight phytotoxin in the patho-
genesis of
Verticillium albo-atrum.
The metabolites separated from 21-day-old culture fil-
trate by adsorption on the
resin Amberlite XAD-4, and furt
her chromatographed on Bio-
Gel P2 polyacrylamide gel, induced chlorosis and necrosis on the leaflets of tomato and
potato cultivars, similar to those caused by
the fungus on diseased plants. Leaflets from
tolerant cultivars were much less sensitive to
the toxin (s) than thos
e from the susceptible
ones. In the presence of toxin(s) plant tissues
and individual cells showed ion-leakage and
cell death to an extent relating to the plants reaction to the fungus. The relative specificity
observed during pathogenicity tests between po
tato and tomato and their related isolates
was shown to be related to the action of toxin (s).
