RESUMEN
Novel flavonoids were formed in young leaves of apple (Malusxdomestica) after treatment with the dioxygenase inhibitor prohexadione-Ca, which is known to reduce the incidence and severity of fire blight caused by Erwinia amylovora and other plant diseases. The compounds were isolated and identified as luteoliflavan, luteoliflavan 5-glucoside, eriodictyol 7-glucoside and 6"-O-trans-p-coumaroyleriodictyol 3'-glucoside. These flavonoids represent a novel biosynthetic pathway in apple leading to the formation of 3-deoxyflavans. Concomitantly, the content of regularly occurring phenylpropanoids is also influenced by prohexadione-Ca with increasing amounts of hydroxycinnamic acids and decreasing flavan-3-ols and flavonols. The altered flavonoid metabolism may be related to the lowered pathogen incidence though the isolated novel flavonoids do not exhibit antibacterial activity.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Flavonoides/biosíntesis , Ácidos Cetoglutáricos/metabolismo , Ácidos Cetoglutáricos/farmacología , Malus/metabolismo , Oxigenasas/antagonistas & inhibidores , Ácido Clorogénico/análisis , Ácidos Cumáricos/análisis , Ácidos Cumáricos/química , Flavanonas/análisis , Flavanonas/química , Flavonoides/análisis , Flavonoides/química , Flavonoides/metabolismo , Malus/efectos de los fármacos , Resonancia Magnética Nuclear Biomolecular , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Espectrofotometría Ultravioleta , Factores de TiempoRESUMEN
Fire blight, a devastating bacterial disease in pome fruits, causes severe economic losses worldwide. Hitherto, an effective control could only be achieved by using antibiotics, but this implies potential risks for human health, livestock and environment. A new approach allows transient inhibition of a step in the flavonoid pathway, thereby inducing the formation of a novel antimicrobial 3-deoxyflavonoid controlling fire blight in apple and pear leaves. This compound is closely related to natural phytoalexins in sorghum. The approach does not only provide a safe method to control fire blight: Resistance against different pathogens is also induced in other crop plants.