An international team of researchers from VIB-UGent Center for Plant Systems Biology and University of Basel has found a link between a class of enzymes and immune signals that is rapidly triggered when plants are damaged.

In plants, damaged cells send out signals to alert the surrounding tissue of the wound. These signals activate the immune system to prevent infection and promote tissue regeneration. Short protein fragments or peptides are important in the plant's immune system. These peptides are produced from precursor proteins that are ‘cut into shape' by so-called proteolytic enzymes or proteases.

There are many proteases, which means that identification of the ones important to the immune system is necessary. The teams wounded the leaves of Arabidopsis and found that a class of proteolytic enzymes called metacaspases played an important role in the plant's response which involves the release of calcium and the peptide precursor protein PROPEP1. To check this finding, they produced a plant with a mutation in the gene coding for an important metacaspase. This plant was unable to release the immune signal. To understand the speed and extent of the immune response in Arabidopsis, Simon Stael, the postdoc who led the efforts, damaged the roots with lasers and found the targeted plant cells responded quickly.

For more details, read the VIB news release.