Induction of antimicrobial 3-deoxyflavonoids in pome fruit trees controls fire blight.

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.

Following spread of fire blight in Western, Central and Southern Europe by molecular differentiation of Erwinia amylovora strains with PFGE analysis.

Fire blight has been detected recently in several areas of northern Spain and north-eastern Italy. To follow spread of the disease within Europe, more than 120 Erwinia amylovora strains isolated from 1957-1900 in England, France, Germany, The Netherlands, Belgium, Poland, Italy and Spain were assayed using pulsed-field gel electrophoresis (PFGE) analysis of genomic DNA after XbaI digestion. Pattern types Pt1 and Pt4 were found for strains from England.