ARBUSCULAR MYCORRHIZAL FUNGUS-INDUCED CHANGES IN THE ACCUMULATION OF SECONDARY COMPOUNDS IN BARLEY ROOTS

Hordeum vulgare (barley) was grown in a defined nutritional medium wit h and without the arbuscular mycorrhizal fungus Glomus intraradices. H PLC of methanolic extracts from the roots of mycorrhized and non-mycor rhized plants revealed fungus-induced accumulation of some secondary m etabolites. These compounds were isolated and identified by spectrosco pic methods (NMR, MS) to be the hydroxycinnamic acid amides N-(E)-4-co umaroylputrescine, N-(E)-feruloylputrescine, N-(E)-4-coumaroylagmatine and N-(E)-feruloylagmatine, exhibiting a transient accumulation, and the cyclohexenone derivative -3-(hydroxymethyl)-5,5-dimethyl-2-cyclohe xen-1-one and -O-beta-glucuronosyl)-beta-glucopyranosyl]-butyl}- 3,5,5 -trimethyl-2-cyclohexen-1-one (blumenin), exhibiting a continuous accu mulation. A third cyclohexenone derivative, yl]-1-butenyl}-3,5,5-trime thyl-2-cyclohexen-1-one, was detectable only in minute amounts. It is suggested that accumulation of the amides in early developmental stage s of barley mycorrhization reflects initiation of a defence response. However, the continuous accumulation of the cyclohexenone derivatives. especially blumenin, seems to correlate with the establishment of a f unctional barley mycorrhiza. Copyright (C) 1997 Elsevier Science Ltd.