title: Proteome analysis of fungal and bacterial involvement in leaf litter decomposition.
abstract: Fungi and bacteria are key players in the decomposition of leaf litter, but their individual contributions to the process and their interactions are still poorly known. We combined semi-quantitative proteome analyses (1-D PAGE-LC-MS/MS) with qualitative and quantitative analyses of extracellular degradative enzyme activities to unravel the respective roles of a fungus and a bacterium during litter decomposition. Two model organisms, a mesophilic Gram-negative bacterium (Pectobacterium carotovorum) and an ascomycete (Aspergillus nidulans), were grown in both, pure culture and co-culture on minimal medium containing either glucose or beech leaf litter as sole carbon source. P. carotovorum grew best in co-culture with the fungus, whereas growth of A. nidulans was significantly reduced when the bacterium was present. This observation suggests that P. carotovorum has only limited capabilities to degrade leaf litter and profits from the degradation products of A. nidulans at the expense of fungal growth. In accordance with this interpretation, our proteome analysis revealed that most of the extracellular biodegradative enzymes (i.e. proteases, pectinases, and cellulases) in the cultures with beech litter were expressed by the fungus, the bacterium producing only low levels of pectinases.
authors.affiliation: Institute of Plant Biology, Department of Microbiology, University of Zurich, Zurich, Switzerland. Thomas.Schneider@botinst.uzh.ch
authors.forename: Thomas
authors.initials: T
authors.lastname: Schneider
authors.forename: Bertran
authors.initials: B
authors.lastname: Gerrits
authors.forename: Regula
authors.initials: R
authors.lastname: Gassmann
authors.forename: Emanuel
authors.initials: E
authors.lastname: Schmid
authors.forename: Mark O
authors.initials: MO
authors.lastname: Gessner
authors.forename: Andreas
authors.initials: A
authors.lastname: Richter
authors.forename: Tom
authors.initials: T
authors.lastname: Battin
authors.forename: Leo
authors.initials: L
authors.lastname: Eberl
authors.forename: Kathrin
authors.initials: K
authors.lastname: Riedel
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology*; D044602:Cellulases / Q000378:metabolism; D016973:Pectobacterium carotovorum / Q000201:enzymology* / Q000254:growth & development; D010447:Peptide Hydrolases / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry* / Q000378:metabolism*; D010940:Plant Proteins / Q000032:analysis*; D011096:Polygalacturonase / Q000378:metabolism; D020543:Proteome / Q000032:analysis*
chemical_list: D010940:Plant Proteins; D020543:Proteome; D044602:Cellulases; D011096:Polygalacturonase; D010447:Peptide Hydrolases