title: Unearthing the Ecology of Soil Microorganisms Using a High Resolution DNA-SIP Approach to Explore Cellulose and Xylose Metabolism in Soil.
abstract: We explored microbial contributions to decomposition using a sophisticated approach to DNA Stable Isotope Probing (SIP). Our experiment evaluated the dynamics and ecological characteristics of functionally defined microbial groups that metabolize labile and structural C in soils. We added to soil a complex amendment representing plant derived organic matter substituted with either (13)C-xylose or (13)C-cellulose to represent labile and structural C pools derived from abundant components of plant biomass. We found evidence for (13)C-incorporation into DNA from (13)C-xylose and (13)C-cellulose in 49 and 63 operational taxonomic units (OTUs), respectively. The types of microorganisms that assimilated (13)C in the (13)C-xylose treatment changed over time being predominantly Firmicutes at day 1 followed by Bacteroidetes at day 3 and then Actinobacteria at day 7. These (13)C-labeling dynamics suggest labile C traveled through different trophic levels. In contrast, microorganisms generally metabolized cellulose-C after 14 days and did not change to the same extent in phylogenetic composition over time. Microorganisms that metabolized cellulose-C belonged to poorly characterized but cosmopolitan soil lineages including Verrucomicrobia, Chloroflexi, and Planctomycetes.
authors.affiliation: School of Integrative Plant Sciences, Cornell University Ithaca, NY, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Pepe-Ranney
authors.affiliation: School of Integrative Plant Sciences, Cornell University Ithaca, NY, USA.
authors.forename: Ashley N
authors.initials: AN
authors.lastname: Campbell
authors.affiliation: School of Integrative Plant Sciences, Cornell University Ithaca, NY, USA.
authors.forename: Chantal N
authors.initials: CN
authors.lastname: Koechli
authors.affiliation: Department of Biological Sciences, Butler University Indianapolis, IN, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Berthrong
authors.affiliation: School of Integrative Plant Sciences, Cornell University Ithaca, NY, USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Buckley
keywords: DNA-SIP; carbon cycle; cellulose; decomposition; soil; stable isotope probing; trophic; verrucomicrobia