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.