Sequestration of polyacetylenes by the parasite Orobanche hederae (Orobanchaceae) from its host Hedera helix (Araliaceae)

Orobanche hederae Duby and its host Hedera helix L. were collected in the North Italian Trentino-Südtirol region and analyzed for their content of polyacetylenes. Both, the host plant (Hedera) and the parasite (Orobanche) contained the polyacetylene falcarinol and two of its dehydroderivatives. The contents of polyacetylenes in Hedera decrease from roots via stems to leaves and contents in Orobanche are only about one-tenth of the contents in the Hedera roots it parasites on. Moreover, relative contents of the more polar polyacetylenes are higher in Orobanche than in Hedera, implying a bias toward the sequestration of more polar compounds.Sequestration of secondary metabolites is a well-known phenomenon in insect–plant interactions. In contrast, sequestration of bioactive secondary metabolites from one species of higher plants to another has received relatively little attention. Furthermore, this is the first report of polyacetylenes being sequestered by another plant species.