Jasmonic acid (JA) and 12-oxophytodienoic acid (OPDA) are signal molecules involved in the stress and defense responses in plants. A full-length cDNA clon of OPR3 encoding 12-oxophytodienoate reductase 3, key enzyme involved in the biosynthesis of JA from linolenic acid was obtained from a Solanum tuberosum cDNA library. Sequence analysis showed that OPR3 encoded a polypeptide of 400 amino acids with a predicted molecular mass of 43.9 kDa and pI of 7.72. The deduced amino acid sequence of OPR3 showed high similarities to other 12-oxophytodienoate reductases. A peroxisomal signal sequence indicates OPR3 probable location in peroxisome. Levels of OPR3 mRNA accumulated in potato leaves reaching maximum levels within 1 hr of mechanical wounding. Elevated levels of JA were correlated to expression of the OPR3 gene.