Phototrophic eukaryotes were established by the engulfment of oxygenic phototrophic prokaryotes (cyanobacteria) by a heterotrophic host. This process, called primary endosymbiosis, gave rise to the taxon Archaeplastida, which comprises green plants, rhodophytes and glaucophytes. Further rounds of endosymbiotic events produced a variety of phototrophic organisms, which could accumulate α-1,4-/α-1,6-glucans (including starch) or β-1,3-/β-1,6-glucans. In this article, we review the recent progress in the study of the intracellular localization and molecular forms of storage glucan, especially starch, among the known phototrophs and related organisms.
2013 by The Japanese Society of Applied Glycoscience