H2020 PhageFire Project: An effective and environmentally friendly solution to control fire blight caused by Erwinia amylovora in pome fruit crops

Innovative Targeted Phage Therapy Eradicates Fire Blight Disease. A team of EU-funded researchers has unveiled a first-of-its-kind technology that uses natural viruses to combat fire blight in pome fruits. This non-toxic solution evolves with bacteria, completely eliminating the disease wherever it resides on the plant.

Fire blight is a devastating bacterial disease caused by Erwinia amylovora that affects many plants in the rose family, especially pome fruits such as apples, pears, and quinces. Originally from North America, it spread to Europe in the 1950s and is now found worldwide, causing significant crop damage each year by infecting blossoms and killing spurs and fruit tissue. Despite strict regulations, it remains the most destructive disease in pome fruit orchards.

The EU-funded PhageFire project aimed to improve fire blight control in pome fruit by developing a biopesticide using bacteriophages (natural viruses) that specifically target Erwinia amylovora strains. These bacteriophages utilize lytic activity, meaning they can penetrate and break down the bacterial cells responsible for fire blight. An environmentally friendly alternative to fire blight control: "Next season, we will be introducing, for the first time on the market, a safe and non-toxic solution for pome fruit growers to combat fire blight using phage therapy," notes project coordinator Borja de Santos Prieto.

"PhageFire is a carefully crafted cocktail containing selected bacteriophages specifically targeting the bacterium Erwinia amylovora, without harming other organisms. Our product can reach bacteria wherever they are found: on flowers, branches, wood, cankers, and other host species; they're not just competing for space," adds de Santos Prieto. "It's environmentally friendly and doesn't generate resistance, aligning with sustainable agricultural practices promoted by the European Commission."

Furthermore, PhageFire comes in a liquid form that is easy to apply using typical agricultural equipment. Overcoming Challenges Characterizing bacteriophages involved intensive laboratory work. It began with the isolation of the bacteriophages and the identification of their genes, followed by testing their lytic capacity and improving their resistance to adverse environmental conditions such as UV radiation. Extensive literature research was also conducted to identify the best ways to protect these cocktails in the laboratory, ensuring they perform well in the field. Project partners conducted more than ten field trials in pome fruit orchards in accordance with European standards. Industrial production technology is now ready to meet demand, with the capacity to produce PhageFire in large 5,000-liter biofermenters. Bright prospects for phage therapies.

Despite its long history, phage research and applications remain a thriving field with immense potential. "Given that phage therapy is really new at this point, our industrial partners have successfully developed a cutting-edge product, positioning PhageFire as a market-leading solution to combat fire blight, a problem that previously lacked a specific remedy," says de Santos Prieto. Thanks to the industrial partners' expertise in bacteriophage applications, there is potential to develop similar technologies for other problems. As the project coordinator points out, current methods are costly and involve removing infected branches, uprooting trees, using copper-based sprays, or nonspecific treatments that fail to eliminate the bacteria.

Therefore, growers are forced to coexist with fire blight bacteria, which leads to inevitable economic and production losses. "PhageFire goes a step further by killing the bacteria, effectively eradicating the disease completely. It leaves no residue, as the bacteriophages degrade naturally once the bacteria are gone. This helps improve the productivity of top fruit growers, ensuring a reliable supply of fruit," concludes de Santos Prieto. Consumers can therefore benefit from more consistent availability and potentially better prices, while enjoying healthier fruit thanks to the reduced need for chemical treatments.