Scientists have tested a new method to protect crops from disease by making the plants manufacture antibiotics derived from bacteria.
They hope it can replace conventional antibiotics used to treat plants, removing a driver of antibiotic resistance that could spread to human diseases.
The team at Glasgow University genetically engineered plants to fight off bacterial infection on their own by producing a targeted protein antibiotic, or bacteriocin.
This was effective against the common crop bacteria Pseudomonas syringae (Ps), which causes diseases including blight and spot.
Researchers claimed Ps is responsible for about 5% of worldwide crop loss, and attacks plants including tomatoes, kiwis, peppers, soybeans, olive and fruit trees.
The team genetically modified plants to manufacture the bacteriocin putidacin L1, which is produced by a harmless soil-living relative of the disease-causing strains of Ps.
The modified test crops produced the bacteriocin throughout their life – the first time this modification has been trialled in plants – and fought off the bacterial infection without any damage to themselves or the environment.
Co-author Joel Milner said: “Our results provide proof of principle that the expression of a bacteriocin in plants can provide effective resistance against bacterial disease.
“Unlike conventional antibiotics, bacteriocins are highly targeted – in this case they act only against the Ps strains that infect plants.
“By using bacteriocins we avoid the risks associated with conventional antibiotics – that resistance will spread indiscriminately to other bacteria.”
Mr Milner added: “In fact, by replacing conventional antibiotics, we take away an important driver of resistance that could even spread to human bacterial pathogens.
“Now we know that expression of bacteriocins in crops can offer an effective strategy for managing bacterial disease, we are undertaking research to fully realise the potential of this novel method.”
Co-author Will Rooney said: “All major bacterial species produce bacteriocins so we should be able to use our research as a blueprint to tackle a wide variety of important bacterial diseases in crops like potato, rice and a variety of fruits.”
The work, funded by the Biotechnology and Biological Sciences Research Council and Wellcome, was published in the Plant Biotechnology Journal.