Insect attack-wound in plant cells stimulate huge number of signal molecules to induce and activate defense system. Among these one of the intracellular signal molecules are small peptide systemin (18AAs long) produced by proteolytic cleavage in wounded cells from prosystemin (200As) precursor protein. Systemin then bind to its SR-160 (Systemin Cell Surface Receptor) protein (160 kD) and activate phospholipase A2 (PLA-2) that releases linolenic acid, which is initial precursor for JA biosynthesis. |
