Transient induction of antimicrobial 3-deoxyflavonoids does not affect pharmacological compounds in hawthorn

Hawthorn (Crataegus sp.) is a traditional medicinal plant, which shows a broad spectrum of health-related effects. Drug preparation is based on material collected from wild growing plants, which usually show variability in their secondary metabolite composition and concentration. Plantations of selected hawthorn genotypes could form the basis of a consistent homogeneous source of top-quality hawthorn drugs. However, as hawthorn is a member of the Rosaceae family, such plantations would be threatened by the bacterial disease fire blight, which currently causes dramatic economic losses in apple and pear orchards. We show that prohexadione-Ca induces the formation in Crataegus monogyna leaves of the rare class of 3-deoxyflavonoids, which are responsible for better fire blight resistance and that the quality and quantity of the health related ingredients are not negatively influenced by prohexadione-Ca treatment.