XVI International Botanical Congess

The expression of lipoxygenase (LOX) and its metabolites were analyzed in potato tubers in response to Rhizoctonia bataticola infection. Rhizoctonia infection in potato tubers induced LOX activity and the formation of 9-hydroperoxyoctadecatrienoic acid (9-HPOTrE). In the uninfected tubers, 9-hydroperoxyoctadecadienoic acid (9-HPODE) is the major product. As a result the relative ratio of HPODE to HPOTrE changed from 4:1 in uninfected to 1:4.5 in infected tubers. Since 9 HPOTrE showed potent antifungal effects, it is suggested that LOX products of ALA may be involved in the potato tuber defense mechanism.