The genome of Cyanothece 51142, a unicellular diazotrophic cyanobacterium important in the marine nitrogen cycle

Journal Article · Tue Sep 30 00:00:00 EDT 2008 · Proceedings of the National Academy of Sciences of the United States of America, 105(39):15094-15099

DOI:https://doi.org/10.1073/pnas.0805418105· OSTI ID:946660

Welsh, Eric A; Liberton, Michelle L; Stockel, Jana; Loh, Thomas; Elvitigala, Thanura R; Wang, Chunyan; Wollam, Aye; Fulton, Robert S; Clifton, Sandra W; Jacobs, Jon M; Aurora, Rajeev; Ghosh, Bijoy K; Sherman, Louis A; Smith, Richard D; Wilson, Richard K; Pakrasi, Himadri B

Cyanobacteria are oxygenic photosynthetic bacteria that have significant roles in global biological carbon sequestration and oxygen production. They occupy a diverse range of habitats, from open ocean, to hot springs, deserts, and arctic waters. Cyanobacteria are known as the progenitors of the chloroplasts of plants and algae, and are the simplest known organisms to exhibit circadian behavior4. Cyanothece sp. ATCC 51142 is a unicellular marine cyanobacterium capable of N2-fixation, a process that is biochemically incompatible with oxygenic photosynthesis. To resolve this problem, Cyanothece performs photosynthesis during the day and nitrogen fixation at night, thus temporally separating these processes in the same cell. The genome of Cyanothece 51142 was completely sequenced and found to contain a unique arrangement of one large circular chromosome, four small plasmids, and one linear chromosome, the first report of such a linear element in a photosynthetic bacterium. Annotation of the Cyanothece genome was aided by the use of highthroughput proteomics data, enabling the reclassification of 25% of the proteins with no informative sequence homology. Phylogenetic analysis suggests that nitrogen fixation is an ancient process that arose early in evolution and has subsequently been lost in many cyanobacterial strains. In cyanobacterial cells, the circadian clock influences numerous processes, including carbohydrate synthesis, nitrogen fixation, photosynthesis, respiration, and the cell division cycle. During a diurnal period, Cyanothece cells actively accumulate and degrade different storage inclusion bodies for the products of photosynthesis and N2-fixation. This ability to utilize metabolic compartmentalization and energy storage makes Cyanothece an ideal system for bioenergy research, as well as studies of how a unicellular organism balances multiple, often incompatible, processes in the same cell.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 946660
• Report Number(s): PNNL-SA-56846; PNASA6; 16720; 14398; 15490; KP1704020; TRN: US200903%%547
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America, 105(39):15094-15099, Vol. 105, Issue 39; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ALGAE
CARBOHYDRATES
CARBON SEQUESTRATION
CELL DIVISION
CHLOROPLASTS
CYANOBACTERIA
ENERGY STORAGE
NITROGEN CYCLE
NITROGEN FIXATION
OXYGEN
PHOTOSYNTHESIS
PHOTOSYNTHETIC BACTERIA
PLASMIDS
PROTEINS
RESPIRATION
STORAGE
STRAINS
SYNTHESIS
Environmental Molecular Sciences Laboratory