Metabolic profiling of oxylipins upon salicylate treatment in barley leaves - preferential induction of the reductase pathway by salicylate

In barley leaves, 13-lipoxygenases (13-LOXs) are induced by salicylate (SA) and jasmonate. Here, we show by metabolic profiling that upon SA treatment, free linolenic acid and linoleic acid accumulate in a 10:1 ratio reflecting their relative occurrence in leaf tissues. Furthermore, 13-LOX-derived products are formed and specifically directed into the reductase branch of the LOX pathway leading mainly to the accumulation of (13S,9Z,11E,15Z)-13-hydroxy-9,11,15-octadecatrienoic acid (13-HOT). Under these conditions, no accumulation of other products of the LOX pathway has been found. Moreover, exogenously applied 13-HOT led to PR1b expression suggesting for the time a role of hydroxy polyenoic fatty acid derivatives in plant defense reactions. (C) 1999 Federation of European Biochemical Societies.