Methyl jasmonate induced accumulation of kalopanaxsaponin I in Nigella sativa.

Hydroponically cultivated Nigella sativa L. plants treated with methyl jasmonate (MeJA) showed a twelve-fold increase in levels of the monodesmosidic triterpene saponins alpha-hederin and kalopanaxsaponin I (KsI) in the leaves. We will demonstrate that these two saponins accounted for approximately 10% of the dry plant matter, of which 93% was KsI and 7% alpha-hederin. To address the molecular basis of saponin induction by MeJA, we cloned and characterized the beta-amyrin synthase gene (NsbetaAS1) encoding one of the key enzymes in triterpene saponin biosynthesis. As expected, NsbetaAS1 transcription was induced by MeJA and led to the production of beta-amyrin when over-expressed in yeast.