title: Abundant Trimethylornithine Lipids and Specific Gene Sequences Are Indicative of Planctomycete Importance at the Oxic/Anoxic Interface in Sphagnum-Dominated Northern Wetlands.
abstract: Northern wetlands make up a substantial terrestrial carbon sink and are often dominated by decay-resistant Sphagnum mosses. Recent studies have shown that planctomycetes appear to be involved in degradation of Sphagnum-derived debris. Novel trimethylornithine (TMO) lipids have recently been characterized as abundant lipids in various Sphagnum wetland planctomycete isolates, but their occurrence in the environment has not yet been confirmed. We applied a combined intact polar lipid (IPL) and molecular analysis of peat cores collected from two northern wetlands (Saxnäs Mosse [Sweden] and Obukhovskoye [Russia]) in order to investigate the preferred niche and abundance of TMO-producing planctomycetes. TMOs were present throughout the profiles of Sphagnum bogs, but their concentration peaked at the oxic/anoxic interface, which coincided with a maximum abundance of planctomycete-specific 16S rRNA gene sequences. The sequences detected at the oxic/anoxic interface were affiliated with the Isosphaera group, while sequences present in the anoxic peat layers were related to an uncultured planctomycete group. Pyrosequencing-based analysis identified Planctomycetes as the major bacterial group at the oxic/anoxic interface at the Obukhovskoye peat (54% of total 16S rRNA gene sequence reads), followed by Acidobacteria (19% reads), while in the Saxnäs Mosse peat, Acidobacteria were dominant (46%), and Planctomycetes contributed to 6% of the total reads. The detection of abundant TMO lipids in planctomycetes isolated from peat bogs and the lack of TMO production by cultures of acidobacteria suggest that planctomycetes are the producers of TMOs in peat bogs. The higher accumulation of TMOs at the oxic/anoxic interface and the change in the planctomycete community with depth suggest that these IPLs could be synthesized as a response to changing redox conditions at the oxic/anoxic interface.
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, Texel, The Netherlands Elisha.Moore@nioz.nl.
authors.forename: Eli K
authors.initials: EK
authors.lastname: Moore
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, Texel, The Netherlands.
authors.forename: Laura
authors.initials: L
authors.lastname: Villanueva
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, Texel, The Netherlands.
authors.forename: Ellen C
authors.initials: EC
authors.lastname: Hopmans
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, Texel, The Netherlands.
authors.forename: W Irene C
authors.initials: WI
authors.lastname: Rijpstra
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, Texel, The Netherlands.
authors.forename: Anchelique
authors.initials: A
authors.lastname: Mets
authors.affiliation: S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia.
authors.forename: Svetlana N
authors.initials: SN
authors.lastname: Dedysh
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, Texel, The Netherlands Utrecht University, Faculty of Geosciences, Utrecht, The Netherlands.
authors.forename: Jaap S
authors.identifier: http://orcid.org/0000-0002-8683-1854
authors.initials: JS
authors.lastname: Sinninghe Damsté
mesh_terms: D061271:Acidobacteria / Q000737:chemistry / Q000302:isolation & purification; D001419:Bacteria / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D059014:High-Throughput Nucleotide Sequencing; D017404:In Situ Hybridization, Fluorescence; D008055:Lipids / Q000032:analysis* / Q000737:chemistry; D010084:Oxidation-Reduction; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012426:Russia; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D044003:Sphagnopsida / Q000737:chemistry / Q000235:genetics / Q000382:microbiology*; D013548:Sweden; D053833:Wetlands
chemical_list: D008055:Lipids; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012987:Soil