TRANSFER OF QUINOLIZIDINE ALKALOIDS FROM VARIOUS HOST PLANTS OF THE FABACEAE TO PARASITIZING CUSCUTA-SPECIES

Transfer of quinolizidine alkaloids from various host plants of the Fabaceae including Cytisus praecox, Chamaecytisus hirsutus, Petteria ramentacea and Spartium junceum to parasitizing Cuscuta species were studied by capillary GLC. Thirty-four quinolizidine alkaloids representing the sparteine type (e.g. sparteine, lupanine, dehydro-, oxo- and hydroxy-derivatives of sparteine and lupanine) as well as the alpha-pyridone type (cytisine, hydroxy-N-methylcytisine, N-formyl- and N-acetylcytisine, N-methylcytisine etc.) were detected in the host plant, whereas Cu. reflexa and Cu. platyloba were found to accumulate only 26 quinolizidine alkaloids. In all host-parasite systems studied, the major alkaloid pattern of the haustorial region of Cuscuta resembled that found in the respective legume host plant, but except for Cu. reflexa growing on Ch. hirsutus differences could be observed as to quantitative composition. Cuscuta reflexa and Cu. platyloba infesting Cy. praecox accumulated preferentially lupanine, whereas both Cuscuta species lacked the alkaloids alpha-isosparteine and 17-oxosparteine which were also absent in the phloem exudate of Cy. praecox. Anagyrine was discriminated both in Cu. reflexa parasitizing on Pe. ramentaceae and in Cu. platyloba infesting Sp. junceum. Similar alkaloid patterns were obtained for Cu. reflexa and Cu. platyloba growing on Cy. praecox indicating that alkaloid uptake and transport within the parasite are independent of the respective Cuscuta species.