Blackleg is an economically damaging agricultural disease that affects a wide range of crops, including carrots, tomatoes and onions but it is best known for causing soft rot in potatoes by producing an enzyme that breaks down the host's cell walls.

Researchers at the University of Cambridge, funded by Britain's Biotechnology and Biological Sciences Research Council, discovered that if they inactivated a gene called relA, the bacteria's ability to export enzymes was also abolished.

"We have shown the production of cell wall degrading enzymes is genetically linked to not only signaling abilities, but also to the bacterium's nutritional status," said research leader Martin Welch. "This has important implications for researchers looking for new ways to control the disease.

"By improving our understanding of how Erwinia carotovora rots the plant, we can reveal additional, possibly novel targets for the eventual development of anti-rot agents," he added. "We have also opened up the potential to develop pesticides."

The research recently appeared in the Journal of Bacteriology.