Methyl jasmonate induced accumulation of kalopanaxsaponin I in Nigella sativa

Hydroponically cultivated Nigella sativa L. plants treated with methyl jasmonate (MeJA) showed a twelvefold 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 (Ns beta AS1) encoding one of the key enzymes in triterpene saponin biosynthesis. As expected, Ns beta AS1 transcription was induced by MeJA and led to the production of p-amyrin when over-expressed in yeast. (C) 2009 Elsevier Ltd. All rights reserved.