Independent evolution of harmala alkaloids in medicinal Syrian rue and ayahuasca plants

Syrian rue (Peganum harmala) and ayahuasca vine (Banisteriopsis caapi) independently evolved harmala alkaloid biosynthesis, revealing convergent enzyme and pathway evolution despite >100 million years divergence.

• Why it matters: Identical neuroactive molecules arise in distantly related plants, but the genetic and biochemical routes behind this convergence—especially for harmala alkaloids used medicinally and ritually—remain unclear.
• What they did: The study combined gene expression analyses, genomics, and enzyme characterization to map harmala alkaloid biosynthesis in both species, identifying independent duplication and neofunctionalization of an ancestral serotonin-biosynthesis enzyme.
• The result: It resolved biosynthetic routes to harmala alkaloids in both plants and shows convergent evolution of specialized metabolism across enzymes, pathways, and genomes.