Scopolin, a Biochemical Marker for Resistance to Thielaviopsis basicola in Callus and Crown-Gall Tissue Cultures of Tobacco

Scopolin concentration increased in tissue cultures where Thielaviopsis basicola growth ceased (primary and established callus cultures of the resistant tobacco cultivar Ky 170) while it decreased in tissue cultures where fungal growth persisted (primary and established callus cultures of the susceptible tobacco cultivar Ky 151 and crown-gall cultures of Ky 170 and Ky 151). The concentration of chlorogenic acid, scopoletin, and two other unknown soluble phenols varied after inoculation and no, correlation with tissue culture resistance could be established. Incorporation of Agrobacterium tumefaciens T-DNA in the genome of both cultivars induced a drastic reduction of scopolin in inoculated tissue cultures. T-DNA incorporation had less, influence on uninoculated tissues. Scopolin at concentrations found in tissue cultures was not toxic to the fungus.