Cis-jasmone is a highly appreciated fragrance and plant-derived signal molecule that controls pollination, attracts parasitoids of attacking herbivores, and serves as an intra- and interspecific signal that controls gene expression. cis-Jasmone is produced from linolenic acid along the jasmonic acid cascade. In addition to the conversion of jasmonic acid into cis-jasmone, a novel pathway might exist that converts cis-oxophytodienoic acid (OPDA), an early precursor of jasmonic acid, into iso-OPDA. The planar iso-OPDA is degraded by beta-oxidation to 3,7-didehydrojasmonic acid, which yields cis-jasmone by spontaneous decarboxylation. The degradation of iso-OPDA to cis-jasmone is demonstrated for many plant species and the yeast Saccharomyces cerevisiae.