title: Who is who in litter decomposition? Metaproteomics reveals major microbial players and their biogeochemical functions.
abstract: Leaf-litter decomposition is a central process in carbon cycling; however, our knowledge about the microbial regulation of this process is still scarce. Metaproteomics allows us to link the abundance and activity of enzymes during nutrient cycling to their phylogenetic origin based on proteins, the 'active building blocks' in the system. Moreover, we employed metaproteomics to investigate the influence of environmental factors and nutrients on the decomposer structure and function during beech litter decomposition. Litter was collected at forest sites in Austria with different litter nutrient content. Proteins were analyzed by 1-D-SDS-PAGE followed by liquid-chromatography and tandem mass-spectrometry. Mass spectra were assigned to phylogenetic and functional groups by a newly developed bioinformatics workflow, assignments being validated by complementary approaches. We provide evidence that the litter nutrient content and the stoichiometry of C:N:P affect the decomposer community structure and activity. Fungi were found to be the main producers of extracellular hydrolytic enzymes, with no bacterial hydrolases being detected by our metaproteomics approach. Detailed investigation of microbial succession suggests that it is influenced by litter nutrient content. Microbial activity was stimulated at higher litter nutrient contents via a higher abundance and activity of extracellular enzymes.
authors.affiliation: Department of Microbiology, Institute of Plant Biology, University of Zurich, Zollikerstrase 107, Zurich, Switzerland. Thomas.Schneider@botinst.uzh.ch
authors.forename: Thomas
authors.initials: T
authors.lastname: Schneider
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Keiblinger
authors.forename: Emanuel
authors.initials: E
authors.lastname: Schmid
authors.forename: Katja
authors.initials: K
authors.lastname: Sterflinger-Gleixner
authors.forename: Günther
authors.initials: G
authors.lastname: Ellersdorfer
authors.forename: Bernd
authors.initials: B
authors.lastname: Roschitzki
authors.forename: Andreas
authors.initials: A
authors.lastname: Richter
authors.forename: Leo
authors.initials: L
authors.lastname: Eberl
authors.forename: Sophie
authors.initials: S
authors.lastname: Zechmeister-Boltenstern
authors.forename: Kathrin
authors.initials: K
authors.lastname: Riedel
mesh_terms: D001317:Austria; D001419:Bacteria / Q000145:classification / Q000235:genetics; D044822:Biodiversity; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005658:Fungi / Q000145:classification / Q000201:enzymology / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D010802:Phylogeny; D018515:Plant Leaves / Q000737:chemistry / Q000382:microbiology*; D020543:Proteome; D040901:Proteomics; D012621:Seasons; D053719:Tandem Mass Spectrometry; D014867:Water / Q000032:analysis
chemical_list: D020543:Proteome; D014867:Water