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| Loy, A; Küsel, K; Lehner, A; Drake, HL; Wagner, M: Microarray and Functional Gene Analyses of Sulfate-Reducing Prokaryotes in Low-Sulfate, Acidic Fens Reveal Cooccurrence of Recognized Genera and Novel Lineages, Applied and Environmental Microbiology, Vol. 70, No. 12, 6998-7009 (2004) | |
Abstract:
Low sulfate, acidic (approximately pH 4) fens at the Lehstenbach catchment (Fichtelgebirge, Germany) are unusual habitats for sulfate-reducing prokaryotes (SRPs) that have been postulated to facilitate the retention of sulfur and protons in these ecosystems. Despite the low in situ availability of sulfate (20 to 200 µM in the soil solution) and acidic conditions (soil and soil solution pHs approximate 4 and 5, respectively), upper peat layers of the soils from two fens (Schlöppnerbrunnen I and II) of this catchment displayed significant sulfate-reducing capacities. 16S rRNA gene-based oligonucleotide microarray analyses revealed stable diversity patterns of recognized SRPs in the upper 30 cm of both fens. Members of the family “Syntrophobacteraceae” were detected in both fens while signals specific for the genus Desulfomonile were only observed in soils from Schlöppnerbrunnen I. These results were confirmed and extended by comparative analyses of environmentally retrieved 16S rRNA and dissimilatory (bi)sulfite reductase (dsrAB) gene sequences; Desulfobacca-like dsrAB sequences were obtained from both fens. Hypotheses on the ecophysiological role of these three SRP groups in the fens were formulated and based on the known physiological properties of their cultured relatives. In addition to these recognized SRP lineages, six novel dsrAB-types that were phylogenetically unrelated to all known SRPs were detected in the fens. These dsrAB sequences had no features indicative of pseudogenes and likely represent novel, deeply branching sulfate- or sulfite-reducing prokaryotes that are specialized colonists of low sulfate habitats. |
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