How was photosynthesis established in eukaryotes? To gain insights into this fundamental step in the evolution of our planet, a grant has been awarded to Dr. Debashish Bhattacharya at the University of Iowa and Dr. Jeffrey Boore at SymBio Corporation to determine to high coverage the 140 million base pair nuclear genome sequence of the unicellular alga Cyanophora paradoxa. Cyanophora is a member of the remaining group of photosynthetic eukaryotes (Glaucophyta) that still lacks a complete genome sequence. The single cyanobacterial primary endosymbiosis that gave rise to all plastids (e.g., chloroplasts) occurred in the common ancestor of Cyanophora, other algae, and plants. This was a pivotal and ancient (~1.5 billion years ago) event in the Earth's history that laid the foundation for modern terrestrial ecosystems. A critical step in plastid establishment was the transfer of endosymbiont genes to the "host" nucleus. It is unclear however whether this massive transfer was limited to genes strictly involved in plastid metabolism or whether the host profited from the captured genome to explore other novel functions via recruitment of genes from the cyanobacterium. The Cyanophora genome sequence will enable scientists to rigorously test this idea in a relatively "simple" algal model. Beyond its contribution to understanding endosymbiosis, the Cyanophora genome sequence will allow countless other insights which include identifying a set of core genes shared by algae and plants that can be studied in detail to understand the origin of plant-specific characters. In addition the Cyanophora genome will be invaluable for guiding the annotation of the genomes of plants and other protists.
Although this is a basic science project, the Cyanophora project has the potential to accelerate education and interest at all levels in protists and their genomes. The research team will incorporate the findings of this study into several outreach efforts. The principles of high throughput genomics will be incorporated into several courses offered at the University of Iowa as well as in the NSF-funded undergraduate summer "Workshop on Comparative Evolutionary Genomics", the findings of the study will be published in the Microbial Life Educational Resources web page at the micro*scope web site http://starcentral.mbl.edu/microscope/portal.php, two graduate students and several undergraduates will be trained at the University of Iowa, and the PI will recruit one or more minority summer student per year through the AGEP program at Iowa.
