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| Titel |
Metaproteome analysis of the microbial community during leaf litter decomposition - the impact of stoichiometry and temperature perturbations |
| VerfasserIn |
K. M. Keiblinger, T. Schneider, S. Leitner, I. Hämmerle, K. Riedel, S. Zechmeister-Boltenstern |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250060696
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| Zusammenfassung |
| Leaf litter decomposition is the breakdown of dead plant material, a terrestrial ecosystem
process of paramount importance. Nutrients released during decomposition play a key role
for microbial growth and plant productivity. These processes are controlled by abiotic factors,
such as climate, and by biotic factors, such as litter nutrient concentration and stoichiometry
(carbon:nutrient ratio) and activity of soil organisms. Future climate change scenarios predict
temperature perturbations, therefore following changes of microbial community
composition and possible feedbacks on ecosystem processes are of key interest;
especially as our knowledge about the microbial regulation of these processes is still
scarce.
Our aim was to elucidate how temperature perturbations and leaf litter stoichiometry
affect the composition of the microbial decomposer community. To this end a terrestrial
microcosm experiment using beech (Fagus sylvatica) litter with different stoichiometry was
conducted. In a semi-quantitative metaproteomics approach (1D-SDS PAGE combined with
liquid chromatography and tandem mass spectrometry; unique spectral counting) we used the
intrinsic metabolic function of proteins to relate specific microbial activities to their
phylogenetic origin in multispecies communities.
Decomposer communities varied on litter with different stoichiometry so that microbial
decomposers (fungi and bacteria) were favoured in litter with narrow C:nutrient ratios. The
fungal community was dominated by Ascomycota (Eurotiomycetes, Sordariomycetes) and
Basidiomycota (Agaricomycetes) and the bacterial community was dominated by
Proteobacteria, Actinobacteria and Firmicutes. The extracellular enzymes we detected
belonged mainly to classes of xylanases, pectinases, cellulases and proteases and were almost
exclusively of fungal origin (particularly Ascomycota). Temperature stress (heat and frost)
evoked strong changes in community composition, enzyme activities, dissolved organic
nitrogen and litter pH. Freeze treatments resulted in increased fungal abundance and a decline
in residual plant litter material, indicating slightly accelerated decomposition. Extracellular
enzyme activities were especially blocked by heat treatment. Using metaproteomics enabled
us to link the composition of the microbial community to its ecosystem function. |
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