Lipoxygenase activity increment in infected tomato [Lycopersicon esculentum] leaves and oxidation product of linolenic acid by its in vitro enzyme reaction

Our previous findings concerning the lipoxygenase (LOX) activity increment in infected rice plants and anti-fungus activity of resulting oxygenated fatty acids have prompted us to examine whether LOX activity increases in higher plants in response to infection with pathogens peculiar to individual plants. This study found that LOX activity increases in several kinds of infected higher plants, particularly in infected tomato leaves. Linolenic acid is oxidized to 9S-hydroperoxy-10E 12Z, 15Z-octadecatrienoic acid by the action of tomato LOX. This finding provides another example concerning the LOX activity increment in infected higher plant. The oxidation products had antimicrobial activity toward several kinds of pathogens.