Presence of proanthocyanidins in mutant green Sarracenia indicate blockage in late anthocyanin biosynthesis between leucocyanidin and pseudobase

Abstract

The insectivorous pitcher plant genus Sarracenia contains several species with mutants which lack red pigment in leaves, flowers and growth point. Mutants and wild-type contain various glycosides of the flavonols quercetin and kaempferol and we hypothesized that the blockage in the mutant occurred between either dihydroflavonols and leucoanthocyanidin or between leucoanthocyanidin and the end product anthocyanin. Acid hydrolysis and acid addition were used to quantify and qualify spectral characteristics of intermediates. Aqueous phase extracts of leaves demonstrated the end product was most likely an anthocyanin because of red color, absorption at 530 nm and miscibility with amyl alcohol. Mutants and wild-type plants in Sarracenia purpurea and S. rubra ssp. jonesii are capable of producing proanthocyanidins while only wild-type contain pseudobase. Sarracenia purpurea mutants had a significantly greater accumulation of proanthocyanidins than wild-type while there was no such significant difference in S. rubra ssp. jonesii. These results suggest that the mutant is blocked in a late stage of anthocyanin biosynthesis between leucocyanidin and pseudobase. While mutants may accumulate precursors, additional investigation is needed. Sarracenia may serve as useful plants for research since the highly modified carnivorous and absorptive leaves may be fed suspected intermediates in this last step of anthocyanin synthesis.