question: Which is the major phytoalexin in alfalfa (Medicago sativa L.)?
answer: The major phytoalexin in alfalfa (Medicago sativa L.) is the isoflavonoid (-)-medicarpin (or 6aR, 11aR)-medicarpin. Medicarpin is synthesized via the isoflavonoid branch of phenylpropanoid metabolism.