Induction of clovamide by jasmonic acid in red clover

The effect of jasmonic acid (JA) on the secondary metabolism of 5-day-old r ed clover seedlings was investigated. Induction of the formation of four co mpounds was found in roots after treatment with 50 mu M JA for 48 h, while no induction was observed in the shoots. These compounds, whose formation w as induced by JA addition, were isolated and identified as caffeoyl DOPA (c lovamide), caffeoyltyrosine, p-coumaroyl DOPA and p-coumaroyltyrosine by io n-spray MS and H-1 NMR analyses, and by chemical synthesis. Among them, clo vamide was the most abundant, while the other amides represented only a min or portion. Clovamide started to increase in amount 24-36 h after treatment and reached a maximum after 96 h (2.81 nmol/mg fr. wt.). The induction of their formation was observed even with 5 mu M of JA, and the amount increas ed with concentrations up to 100 mu M. Treatment with 1 mM CuCl2, which eli cits accumulation of the phytoalexin maackiain in red clover, caused a decr ease in clovamide amount. (C) 2000 Elsevier Science Ltd. All lights reserve d.