title: Differential Response of Acidobacteria Subgroups to Forest-to-Pasture Conversion and Their Biogeographic Patterns in the Western Brazilian Amazon.
abstract: Members of the phylum Acidobacteria are among the most abundant soil bacteria on Earth, but little is known about their response to environmental changes. We asked how the relative abundance and biogeographic patterning of this phylum and its subgroups responded to forest-to-pasture conversion in soils of the western Brazilian Amazon. Pyrosequencing of 16S rRNA genes was employed to assess the abundance and composition of the Acidobacteria community across 54 soil samples taken using a spatially nested sampling scheme at the landscape level. Numerically, Acidobacteria represented 20% of the total bacterial community in forest soils and 11% in pasture soils. Overall, 15 different Acidobacteria subgroups of the current 26 subgroups were detected, with Acidobacteria subgroups 1, 3, 5, and 6 accounting together for 87% of the total Acidobacteria community in forest soils and 75% in pasture soils. Concomitant with changes in soil chemistry after forest-to-pasture conversion-particularly an increase in properties linked to soil acidity and nutrient availability-we observed an increase in the relative abundances of Acidobacteria subgroups 4, 10, 17, and 18, and a decrease in the relative abundances of other Acidobacteria subgroups in pasture relative to forest soils. The composition of the total Acidobacteria community as well as the most abundant Acidobacteria subgroups (1, 3, 5, and 6) was significantly more similar in composition across space in pasture soils than in forest soils. These results suggest that preponderant responses of Acidobacteria subgroups, especially subgroups 1, 3, 4, 5, and 6, to forest-to-pasture conversion effects in soils could be used to define management-indicators of agricultural practices in the Amazon Basin. These acidobacterial responses are at least in part through alterations on acidity- and nutrient-related properties of the Amazon soils.
authors.affiliation: Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo Piracicaba, Brazil.
authors.forename: Acacio A
authors.initials: AA
authors.lastname: Navarrete
authors.affiliation: Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo Piracicaba, Brazil.
authors.forename: Andressa M
authors.initials: AM
authors.lastname: Venturini
authors.affiliation: Department of Biology, Institute of Ecology and Evolution, University of Oregon Eugene, OR, USA.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Meyer
authors.affiliation: Department of Biology, Institute of Ecology and Evolution, University of Oregon Eugene, OR, USA.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Klein
authors.affiliation: Department of Plant, Soil and Microbial Sciences, Center for Microbial Ecology, Michigan State University East Lansing, MI, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Tiedje
authors.affiliation: Department of Biology, Institute of Ecology and Evolution, University of Oregon Eugene, OR, USA.
authors.forename: Brendan J M
authors.initials: BJ
authors.lastname: Bohannan
authors.affiliation: Department of Microbiology, University of Massachusetts Amherst, MA, USA.
authors.forename: Klaus
authors.initials: K
authors.lastname: Nüsslein
authors.affiliation: Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo Piracicaba, Brazil.
authors.forename: Siu M
authors.initials: SM
authors.lastname: Tsai
authors.affiliation: Department of Land, Air and Water Resources, University of California, Davis Davis, CA, USA.
authors.forename: Jorge L M
authors.initials: JL
authors.lastname: Rodrigues
keywords: 16S rRNA gene; Acidobacteria; community similarity; land-use change; spatial scale; tropical rainforest