The Transcriptional Cycle Is Suited to Daytime N₂ Fixation in the Unicellular Cyanobacterium "Candidatus Atelocyanobacterium thalassa" (UCYN-A).

ABSTRACT: Symbiosis between a marine alga and a N₂-fixing cyanobacterium (Cyanobacterium UCYN-A) is geographically widespread in the oceans and is important in the marine N cycle. UCYN-A is uncultivated and is an unusual unicellular cyanobacterium because it lacks many metabolic functions, including oxygenic photosynthesis and carbon fixation, which are typical in cyanobacteria. It is now presumed to be an obligate symbiont of haptophytes closely related to Braarudosphaera bigelowii N₂-fixing cyanobacteria use different strategies to avoid inhibition of N₂ fixation by the oxygen evolved in photosynthesis. Most unicellular cyanobacteria temporally separate the two incompatible activities by fixing N₂ only at night, but, surprisingly, UCYN-A ap

SUBMITTER: Munoz-Marin MDC 

PROVIDER: S-EPMC6315102 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature