<i>Cyanophora paradoxa</i> Genome Elucidates Origin of Photosynthesis in Algae and Plants

TLDR

The primary endosymbiotic origin of the plastid in eukaryotes more than 1 billion years ago led to the evolution of algae and plants. The study analyzes draft genome and transcriptome data from the basally diverging alga Cyanophora paradoxa to provide evidence for a single origin of the primary plastid in the eukaryote supergroup Plantae. The authors examined draft genome and transcriptome data from Cyanophora paradoxa to investigate plastid origins. C.

Abstract

The primary endosymbiotic origin of the plastid in eukaryotes more than 1 billion years ago led to the evolution of algae and plants. We analyzed draft genome and transcriptome data from the basally diverging alga Cyanophora paradoxa and provide evidence for a single origin of the primary plastid in the eukaryote supergroup Plantae. C. paradoxa retains ancestral features of starch biosynthesis, fermentation, and plastid protein translocation common to plants and algae but lacks typical eukaryotic light-harvesting complex proteins. Traces of an ancient link to parasites such as Chlamydiae were found in the genomes of C. paradoxa and other Plantae. Apparently, Chlamydia-like bacteria donated genes that allow export of photosynthate from the plastid and its polymerization into storage polysaccharide in the cytosol.