Peatland Acidobacteria with a dissimilatory sulfur metabolism

摘要: Sulfur-cycling microorganisms impact organic matter decomposition in wetlands and consequently greenhouse gas emissions from these globally relevant environments. However, their identities physiological properties are largely unknown. By applying a functional metagenomics approach to an acidic peatland, we recovered draft genomes of seven novel Acidobacteria species with the potential for dissimilatory sulfite (dsrAB, dsrC, dsrD, dsrN, dsrT, dsrMKJOP) or sulfate respiration (sat, aprBA, qmoABC plus dsr genes). Surprisingly, also encoded DsrL, which so far was only found sulfur-oxidizing microorganisms. Metatranscriptome analysis demonstrated expression acidobacterial sulfur-metabolism genes native peat soil upregulation diverse anoxic microcosms. This indicated active pathway, which, however, might operate reverse sulfur oxidation disproportionation as proposed Desulfurivibrio alkaliphilus. that harbored reduction additionally enzymes liberate organosulfonates, suggested compounds complementary energy sources. Further metabolic potentials included polysaccharide hydrolysis sugar utilization, aerobic respiration, several fermentative capabilities, hydrogen oxidation. Our findings extend both, known genetic taxonomic diversity DsrAB-based metabolism, highlight new fundamental niches facultative anaerobic based on exploitation inorganic molecules conservation.