Chlorophyll [formula omitted] and [formula omitted] and extraplastidic carotenoids in the dinoflagellate, Peridinium foliaceum stein

Abstract

Chlorophyll c 1 and c 2 as well as fucoxanthin have been found in the binucleate dinoflagellate, Peridinium foliaceum Stein. These pigments are not characteristic of the Pyrrophyta, as typical dinoflagellates contain peridinin, not fucoxanthin, and only chlorophyll c 2 . Thus the chloroplast pigment composition of P. foliaceum lends support to the hypothesis that this species is a heterotrophic dinoflagellate hosting an algal symbiont of non-dinoflagellate origin, and is consistent with the assignment of the endosymbiont to the Chrysophyta. An investigation of the carotenes of P. foliaceum has revealed the presence of both β-carotene and γ-carotene, as well as the colorless carotenoid precursors, phytoene and phytofluene. Typically only β-carotene occurs in photosynthetic pyrrophytes and chrysophytes. Phytoene and phytofluene have not been previously detected in any naturally occurring photosynthetic alga. Preliminary evidence indicates that these unusual hydrocarbons specifically accumulate in extraplastidic oil globules in P. foliaceum, and the speculation is made that these carotenes pertain to the apochlorotic host dinoflagellate and do not originate from the chloroplasts of the endosymbiont.