Unusual marine unicellular symbiosis with the nitrogen-fixing cyanobacterium UCYN-A
2017 (English)In: Nature Microbiology, E-ISSN 2058-5276, Vol. 2, no 1, 16214Article, review/survey (Refereed) Published
Nitrogen fixation - the reduction of dinitrogen (N-2) gas to biologically available nitrogen (N) - is an important source of N for terrestrial and aquatic ecosystems. In terrestrial environments, N-2-fixing symbioses involve multicellular plants, but in the marine environment these symbioses occur with unicellular planktonic algae. An unusual symbiosis between an uncultivated unicellular cyanobacterium (UCYN-A) and a haptophyte picoplankton alga was recently discovered in oligotrophic oceans. UCYN-A has a highly reduced genome, and exchanges fixed N for fixed carbon with its host. This symbiosis bears some resemblance to symbioses found in freshwater ecosystems. UCYN-A shares many core genes with the 'spheroid bodies' of Epithemia turgida and the endosymbionts of the amoeba Paulinella chromatophora. UCYN-A is widely distributed, and has diversified into a number of sublineages that could be ecotypes. Many questions remain regarding the physical and genetic mechanisms of the association, but UCYN-A is an intriguing model for contemplating the evolution of N-2-fixing organelles.
Place, publisher, year, edition, pages
Nature Publishing Group, 2017. Vol. 2, no 1, 16214
Research subject Ecology, Microbiology
IdentifiersURN: urn:nbn:se:lnu:diva-62066DOI: 10.1038/nmicrobiol.2016.214ISI: 000396366300020PubMedID: 27996008OAI: oai:DiVA.org:lnu-62066DiVA: diva2:1086624