Distribution of acI-Actinorhodopsin genes in Baltic Sea salinity gradients indicates adaptation of facultative freshwater photoheterotrophs to brackish waters
2014 (English)In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 16, no 2, 586-597 p.Article in journal (Refereed) PublishedText
Knowledge onActinobacteriarhodopsin gene (actR)diversity and spatial distribution is scarce. The BalticSea is characterized by strong salinity gradientsleading to the coexistence of marine and freshwaterbacteria and hence is an ideal study area to elucidatethe dispersion and phylogenetic affiliation ofactRindependence on salinity. ActRDGGE fingerprints insummer 2008 revealed between 3 and 19 distinctbands within a salinity range of 2.4–27 PSU. Environ-mentalactRclone sequences were obtained from sta-tions distributed along the whole salinity gradient.Overall, 20 differentactRsequence groups (opera-tional taxonomic units) were found, with up to 11different ones per station. Phylogenetically, theactRsequences were predominantly (80%) affiliated with freshwater acI-Actinobacteriawhose 16S rRNA geneaccounted for 2–33% of total 16S rRNA genes in both the Bothnian Sea and central Baltic Sea. However, atsalinities above 14 PSU, acI-16S rRNA gene accounted for less than 1%. In contrast, the diversity of actRremained high. Changes in actRgene diversity were significantly correlated with salinity, oxygen, silica orabundance of Synechococcussp. Our results demonstrate a wide distribution of freshwater actRalong theBaltic Sea salinity gradient indicating that some fresh-water Actinobacteriamight have adapted to higher salinities.
Place, publisher, year, edition, pages
2014. Vol. 16, no 2, 586-597 p.
IdentifiersURN: urn:nbn:se:uu:diva-279795DOI: 10. 1111/1462-2920.12185OAI: oai:DiVA.org:uu-279795DiVA: diva2:908958