I t is well established that chloroplasts in green and red algae are derived from a primary endosymbiotic event between a cyanobacterium and a eukaryotic organism 1 billion years ago (Fig. 1; refs. 1 and 2). Although these two groups account for many of the world’s photosynthetic species, most other major taxonomic groups of photosynthetic organisms (stramenopiles—including diatoms, phaeophytes...

The dinoflagellates are a large group of unicellular alge in marine and fresh water. Some are an endosymbiont of marine animals. Photosynthetic dinoflagellates have peridinin, a light-harvesting carotenoid. In addition, a unique carotenoid, P457, was found from Amphinidium. The presence of P457 in Symbiodinium derived from marine animals has not been reported. We reconfirmed the molecular struc...

Relative to the large number of photosynthetic dinoflagellate species, only a select few possess proteinaceous, carotenoid-rich eyespots which have been demonstrated in other algae act phototactic responses. The proteins comprising different categories are positioned or near peridinin-containing plastid membranes composed primarily two galactolipids, mono- and digalactosyldiacylglycerol (MGDG D...