Lipidomics und funktionelle Genetik des terrestrischen mikrobiellen Stickstoffkreislaufs

• Antragsteller: Professor Dr. Lorenz Schwark
• Fachliche Zuordnung: Mineralogie, Petrologie und Geochemie
• Förderung: Förderung von 2013 bis 2018
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 235042618

The nitrogen cycle as a key element in shaping the biosphere is influenced by microbes capable of N fixation and transformation into components suitable for macrobiota. These complex reactions are carried out by a large variety of microbes, many of which are still uncultivable and hence poorly known. Progress in microbial ecology via genetics and proteomics in the last two decades has shown the N-cycle to be far more complex than previously thought. We here propose to extend knowledge on N-cycling microbes by complementary application of lipidomics to a variety of samples from highly diverse terrestrial ecosystems (upland and paddy soil, tidal flat, marsh, lake, river, wetland, peat), where molecular genetic characterization has been conducted already and will be extended by the co-PIs. Thus a very significant scientific progress can be achieved at excellent return on investment costs. Statistical treatment of lipidomics and functional genetics data sets will facilitate attributing diagnostic membrane lipids to specific microbial producers. Based on previous work we propose the GDGT thaumarchaeol to be diagnostic for archaeal nitrifiers, caldarchaeol isomers for methanogenic euryarchaea, branched GDGT and C19cyclopropyl-PLFA for denitrifying bacteria, heterocyst glycolipids for cyanophytes, and ladderanes for anammox bacteria. Different time domains will be covered by intact polar phospho- and glycolipids from viable biomass and core lipids integrating microbial communities and activity over centennia/millennia. In parallel it is envisaged to verify denitrifying bacteria as a source for ubiquitous branched GDGT of unknown biosynthetic origin that are empirically used as molecular paleothermometers.

• DFG-Verfahren: Sachbeihilfen
• Internationaler Bezug: China
• Großgeräte: Präparative HPLC
• Gerätegruppe: 1350 Flüssigkeits-Chromatographen (außer Aminosäureanalysatoren 317), Ionenaustauscher
• Beteiligte Personen: Dr. Li-Mei Zhang; Professor Guibing Zhu, Ph.D.