Phage therapy against pear and apple fire blight

Fire blight caused by the bacterium Erwinia amylovora (Ea) is one of the most serious infectious diseases of pome fruits. The invention is about the use of a bacteriophage as biological control of pomaceous fire blight.

Title of the patent Composition and method for preventing infections of vegetable tissues caused by Erwinia amylovora
Thematic area Chemistry and biotechnology
Ownership Alma Mater Studiorum – Università di Bologna
Inventors Umberto Mazzucchi, Carla Lucchese, Antonio Mazzucchi
Protection Italy
Licensing status Available for licensing agreement
Keywords Fire blight , Erwinia amylovora, phage therapy, biological control, lytic phage, pome
Filed on Apr 30, 2013

Fire blight caused by the bacterium Erwinia amylovora (Ea) is one of the most serious infectious diseases of pome fruits. The disease endemic exposes the fruit growers to the risk of serious direct (e.g. crop loss, fight costs) and indirect (e.g. future productive capacity of the orchard) damage. In favorable weather conditions, the disease can destroy an orchard of young trees during a single growing season.

The invention foresees the use of the phage M9, lytic for Ea (primary target), selected for its ability to cause lysis in 29 Ea strains typical of Northern Italy and to be propagated in laboratory on a strain of Pantoea vagans, a saprophytic, non-pathogenic enterobacterium (secondary target), which commonly cohabits as epiphyte in the same niche of the pathogen Ea. Consequently the lytic M9 phages, distributed well in advance on pomaceous trees, are able to persist indefinitely at the expense of the secondary target populations and may already be present on the host plant at the moment of immigration of Ea cells.

Phage M9 only multiplies in the presence of the target bacterium or bacteria taxonomically closely related to it; it disappears rapidly from the niche on which it is applied in the absence of target bacteria; it can be applied simultaneously with eukaryotic or prokaryotic organisms used as biopharmaceutical antagonists or competitors of harmful even when they differ from the secondary target in the same sub-ecosystem, possibly enhancing the effect. Phage M9 lacks of toxicity or adverse effects to eukaryotic organisms. With the aim of controlling fire blight in pome fruits, the invention can replace both copper and antibiotics and can be alternative or complementary or synergistic to other bio-pharmaceuticals. The permanence of phage M9, highly conditioned by environmental and microbial factors, can be ensured through the presence of wild strains of P.vagans or other P.vagans-related enterobacteria in the environment. The phage can be conveyed ahead by the contamination of the soil in which the plants are sold.