title: Metagenomic analyses reveal no differences in genes involved in cellulose degradation under different tillage treatments.
abstract: Incorporation of plant litter is a frequent agricultural practice to increase nutrient availability in soil, and relies heavily on the activity of cellulose-degrading microorganisms. Here we address the question of how different tillage treatments affect soil microbial communities and their cellulose-degrading potential in a long-term agricultural experiment. To identify potential differences in microbial taxonomy and functionality, we generated six soil metagenomes of conventional (CT) and reduced (RT) tillage-treated topsoil samples, which differed in their potential extracellular cellulolytic activity as well as their microbial biomass. Taxonomic analysis of metagenomic data revealed few differences between RT and CT, and a dominance of Proteobacteria and Actinobacteria, whereas eukaryotic phyla were not prevalent. Prediction of cellulolytic enzymes revealed glycoside hydrolase families 1, 3 and 94, auxiliary activity family 8 and carbohydrate-binding module 2 as the most abundant in soil. These were annotated mainly to the phyla of Proteobacteria, Actinobacteria and Bacteroidetes. These results suggest that the observed higher cellulolytic activity in RT soils can be explained by a higher microbial biomass or changed expression levels but not by shifts in the soil microbiome. Overall, this study reveals the stability of soil microbial communities and cellulolytic gene composition under the investigated tillage treatments.
authors.affiliation: Environmental Genomics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: de Vries
authors.affiliation: Environmental Genomics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany anne.schoeler@helmholtz-muenchen.de.
authors.forename: Anne
authors.initials: A
authors.lastname: Schöler
authors.affiliation: Environmental Genomics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Ertl
authors.affiliation: University of Copenhagen, Microbiology, Universitetsparken 15, 2100 København Ø, Denmark.
authors.forename: Zhuofei
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Environmental Genomics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schloter
mesh_terms: D039903:Actinobacteria / Q000145:classification* / Q000201:enzymology / Q000235:genetics; D000383:Agriculture / Q000379:methods; D041963:Bacteroidetes / Q000145:classification* / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D002482:Cellulose / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D056890:Eukaryota / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics*; D054892:Metagenome / Q000235:genetics; D056186:Metagenomics; D020560:Proteobacteria / Q000145:classification* / Q000201:enzymology / Q000235:genetics; D017422:Sequence Analysis, DNA; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D012987:Soil; D002482:Cellulose; D006026:Glycoside Hydrolases
keywords: Agriculture; Cellulases; Cellulose degradation; Metagenomics; Microbial Communities; Reduced Tillage