The identified receptor is called FLS3 (an abbreviation for flagellin-sensing receptor 3). As well as tomatoes, the receptor is found in potatoes and peppers. The receptor has been identified by scientists working at the Boyce Thompson Institute and Virginia Tech.
In these particular crops, the receptor senses a particular type of crop-damaging bacterial disease and allows the plant to halt the rate of infection spread. The receptor detects an appendage on the invasive bacterial species called the flagellum (which helps the bacterium move through a fluid). On sensing the organism, the FLS3 receptor binds to a flagellin protein (called flgII-28) and this initiates an immune response against the bacterium.
Bacterial speck is caused by a bacterium called Pseudomonas syringae. Damage from the disease ranges from a light spotting of the foliage to almost complete defoliation of the plant. It can devastate an entire crop.
The receptor was identified because not all tomatoes seem to possess it. For example, the researchers discovered that the Yellow Pear tomato did not respond to flgII-28. By examining the differences between different tomato plants, the receptor was pinpointed.
Commenting on the future possibilities, lead scientist Professor Gregory Martin explains: “This is an interesting example of a receptor that appears to have evolved fairly recently because it is only found in a small group of plants. This discovery sets up the possibility of introducing FLS3 into other economically important crop plants, which might provide resistance to bacterial pathogens that is not naturally present in other plants.”
Such genetic modification will not be straightforward and more work is required to assess how two molecules can physically interact.
The identification of the receptor has been described in the journal Nature Plants. The research article is titled “Tomato receptor FLAGELLIN-SENSING 3 binds flgII-28 and activates the plant immune system.”
