Distinct ecological niches of marine symbiotic N2-fixing cyanobacterium Candidatus Atelocyanobacterium thalassa sublineages
2017 (English)In: Journal of Phycology, ISSN 0022-3646, E-ISSN 1529-8817Article in journal (Refereed) Epub ahead of print
A recently described symbiosis between the metabolically streamlined nitrogen-fixing cyanobacterium UCYN-A and a single-celled eukaryote prymnesiophyte alga is widely distributed throughout tropical and subtropical marine waters, and is thought to contribute significantly to nitrogen fixation in these regions. Several UCYN-A sublineages have been defined based on UCYN-A nitrogenase (nifH) sequences. Due to the low abundances of UCYN-A in the global oceans, currently existing molecular techniques are limited for detecting and quantifying these organisms. A targeted approach is needed to adequately characterize the diversity of this important marine cyanobacterium, and to advance understanding of its ecological importance. We present findings on the distribution of UCYN-A sublineages based on high throughput sequencing of UCYN-A nifH PCR amplicons from 78 samples distributed throughout many major oceanic provinces. These UCYN-A nifH fragments were used to define oligotypes, alternative taxonomic units defined by nucleotide positions with high variability. The data set was dominated by a single oligotype associated with the UCYN-A1 sublineage, consistent with previous observations of relatively high abundances in tropical and subtropical regions. However, this analysis also revealed for the first time the widespread distribution of the UCYN-A3 sublineage in oligotrophic waters. Furthermore, distinct assemblages of UCYN-A oligotypes were found in oligotrophic and coastally influenced waters. This unique data set provides a framework for determining the environmental controls on UCYN-A distributions and the ecological importance of the different sublineages.
Place, publisher, year, edition, pages
John Wiley & Sons, 2017.
Candidatus Atelocyanobacterium thalassa, UCYN-A, nifH, Nitrogen fixation, Nitrogenase, Oligotyping
Research subject Ecology, Microbiology
IdentifiersURN: urn:nbn:se:lnu:diva-62271DOI: 10.1111/jpy.12505PubMedID: 27992651OAI: oai:DiVA.org:lnu-62271DiVA: diva2:1088522