Arabidopsis uses molecular decoy to trick pathogens

In the animal kingdom, predators use a full range of strategies, such as camouflage, speed and optical illusions, to catch their prey. Meanwhile, prey species resort to the same tactics to escape from their predators.

Such tricks are also used at the molecular level, as discovered by researchers from the CNRS, INRA, CEA and INSERM in one of the most devastating bacterial plant pathogens in the world, which bypasses plant cell defenses by preventing an immune signaling from being triggered.

Even more surprising is the fact that plant cells have developed a receptor incorporating a decoy intended to catch the invader in its own trap.

As in humans, interception of pathogens by the immune system is essential for plants, allowing them to ensure their survival, growth and productivity. Their defense responses rely entirely on genetic resistance (innate immunity) conferred by a family of receptors expressed in individual cells. These receptors are inactive until they are activated following recognition of specific pathogenic molecules, called effectors, whose objective is often to block immune pathways.

The speed at which microbial pathogens can produce new effectors that promote infection puts considerable pressure on plants, forcing them to constantly acquire new detection capabilities.

In this article, published in the journal Cell, the researchers describe a particularly ingenious defense mechanism in the model plant Arabidopsis. This mechanism enables the plant to convert the virulence activity of a bacterial effector into a trigger for a rapid immune response.