During pathogen attacks, plants activate a molecular signaling cascade to switch on its defense mechanisms, one of which involves sacrificing host cells to the pathogen. This process is called cell death response and ensures that only a few host cells die. Tomatoes use this mechanism when they are attacked by a bacterial pathogen known as Pseudomonas syringae pv. tomato, which causes speck disease.

In a study at Boyce Thompson Institute, scientists introduce a protein, called Mai1, which plays a role in this missing link. They found that when the expression of Mai1 is muted, the plants could no longer defend themselves against pathogens using the cell death response. As a result, these plants were more susceptible to bacterial infection.

The identification of this protein as a central regulator of immunity in tomato has advanced the understanding of plant signaling mechanisms. The research suggests that Mai1 has a central role in immunity that likely can not be substituted by other proteins.

For more details, read the news article from the University of Illinois Crop Sciences and the research article in Molecular Plant-Microbiome Interactions.