Active bacterioplankton community response to dissolved ‘free’ deoxyribonucleic acid (dDNA) in surface coastal marine waters

Taylor, JD; Bird, KE; Widdicome, CE; Cunliffe, M

Abstract

Seawater contains dissolved ‘free’ DNA (dDNA) that is part of a larger <0.2 μm pool of DNA (D-DNA) including viruses and uncharacterised bound DNA. Previous studies have shown that bacterioplankton readily degrade dDNA and culture-based approaches have identified several potential dDNA-utilising taxa. This study characterised the seasonal variation in D-DNA concentrations at Station L4, a coastal marine observatory in the Western English Channel, and linked changes in concentration to cognate physicochemical and biological factors. The impact of dDNA addition on active bacterioplankton communities at Station L4 was then determined using 16S rRNA high-throughput sequencing and RNA Stable Isotope Probing (RNA SIP) with 13C-labelled diatom-derived dDNA. Compared to other major bacterioplankton orders, the Rhodobacterales actively responded to dDNA additions in amended microcosms and RNA SIP identified two Rhodobacterales populations most closely associated with the genera Halocynthiibacter and Sulfitobacter that assimilated the 13C-labelled dDNA. Here we demonstrate that dDNA is a source of dissolved organic carbon for some members of the major bacterioplankton group the Marine Roseobacter Clade. This study enhances our understanding of roles of specific bacterioplankton taxa in dissolved organic matter cycling in coastal waters with potential implications for nitrogen and phosphorus regeneration processes.

Citation

Taylor, J., Bird, K., Widdicome, C., & Cunliffe, M. (2018). Active bacterioplankton community response to dissolved ‘free’ deoxyribonucleic acid (dDNA) in surface coastal marine waters. FEMS Microbiology Ecology, 94(10), https://doi.org/10.1093/femsec/fiy132

• Journal Article Type: Article
• Acceptance Date: Jul 10, 2018
• Online Publication Date: Jul 13, 2018
• Publication Date: Jul 13, 2018
• Deposit Date: Jul 30, 2018
• Publicly Available Date: Jul 13, 2019
• Journal: FEMS Microbiology Ecology
• Print ISSN: 0168-6496
• Electronic ISSN: 1574-6941
• Publisher: Oxford University Press
• Volume: 94
• Issue: 10
• DOI: https://doi.org/10.1093/femsec/fiy132
• Publisher URL: https://doi.org/10.1093/femsec/fiy132
• Related Public URLs: https://academic.oup.com/femsec