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Unicellular cyanobacterium symbiotic with a single-celled eukaryotic alga

TitleUnicellular cyanobacterium symbiotic with a single-celled eukaryotic alga
Publication TypeJournal Article
Year of Publication2012
AuthorsThompson AW, Foster RA, Krupke A, Carter BJ, Musat N, Vaulot D, Kuypers MMM, Zehr JP
JournalScience
Volume337
Pagination1546–1550
Keywords2012, MicroB3, rcc, sbr{\_}phyto{\_}dipo, SBR{\_}Phyto{\_}DPO
Abstract

Symbioses between nitrogen (N)2–fixing prokaryotes and photosynthetic eukaryotes are important for nitrogen acquisition in N-limited environments. Recently, a widely distributed planktonic uncultured nitrogen-fixing cyanobacterium (UCYN-A) was found to have unprecedented genome reduction, including the lack of oxygen-evolving photosystem II and the tricarboxylic acid cycle, which suggested partnership in a symbiosis. We showed that UCYN-A has a symbiotic association with a unicellular prymnesiophyte, closely related to calcifying taxa present in the fossil record. The partnership is mutualistic, because the prymnesiophyte receives fixed N in exchange for transferring fixed carbon to UCYN-A. This unusual partnership between a cyanobacterium and a unicellular alga is a model for symbiosis and is analogous to plastid and organismal evolution, and if calcifying, may have important implications for past and present oceanic N2 fixation.

URLhttp://www.sciencemag.org/content/337/6101/1546.abstract
DOI10.1126/science.1222700