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 Fa baceae including Cytisus praecox, Chamaecytisus hirsutus, Petteria ram entacea and Spartium junceum to parasitizing Cuscuta species were stud ied by capillary GLC. Thirty-four quinolizidine alkaloids representing the sparteine type (e.g. sparteine, lupanine, dehydro-, oxo- and hydr oxy-derivatives of sparteine and lupanine) as well as the alpha-pyrido ne type (cytisine, hydroxy-N-methylcytisine, N-formyl- and N-acetylcyt isine, N-methylcytisine etc.) were detected in the host plant, whereas Cu. reflexa and Cu. platyloba were found to accumulate only 26 quinol izidine alkaloids. In all host-parasite systems studied, the major alk aloid pattern of the haustorial region of Cuscuta resembled that found in the respective legume host plant, but except for Cu. reflexa growi ng on Ch. hirsutus differences could be observed as to quantitative co mposition. Cuscuta reflexa and Cu. platyloba infesting Cy. praecox acc umulated preferentially lupanine, whereas both Cuscuta species lacked the alkaloids alpha-isosparteine and 17-oxosparteine which were also a bsent in the phloem exudate of Cy. praecox. Anagyrine was discriminate d both in Cu. reflexa parasitizing on Pe. ramentaceae and in Cu. platy loba infesting Sp. junceum. Similar alkaloid patterns were obtained fo r 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.