TY - JOUR
T1 - Selection for Cu-tolerant bacterial communities with altered composition, but unaltered richness, via long-term Cu exposure
AU - Berg, Jeanette
AU - Brandt, Kristian Koefoed
AU - Abu Al-Soud, Waleed
AU - Holm, Peter Engelund
AU - Hansen, Lars H.
AU - Sørensen, Søren Johannes
AU - Nybroe, Ole
PY - 2012/10
Y1 - 2012/10
N2 - Toxic metal pollution affects the composition and metal tolerance of soil bacterial communities. However, there is virtually no knowledge concerning the responses of members of specific bacterial taxa (e.g., phyla or classes) to metal toxicity, and contradictory results have been obtained regarding the impact of metals on operational taxonomic unit (OTU) richness. We used tagcoded pyrosequencing of the 16S rRNA gene to elucidate the impacts of copper (Cu) on bacterial community composition and diversity within a well-described Cu gradient (20 to 3,537 μg g-1) stemming from industrial contamination with CuSO4 more than 85 years ago. DNA sequence information was linked to analysis of pollution-induced community tolerance (PICT) to Cu, as determined by the [3H]leucine incorporation technique, and to chemical characterization of the soil. PICT was significantly correlated to bioavailable Cu, as determined by the results seen with a Cu-specific bioluminescent biosensor strain, demonstrating a specific community response to Cu. The relative abundances of members of several phyla or candidate phyla, including the Proteobacteria, Bacteroidetes, Verrumicrobia, Chloroflexi, WS3, and Planctomycetes, decreased with increasing bioavailable Cu, while members of the dominant phylum, the Actinobacteria, showed no response and members of the Acidobacteria showed a marked increase in abundance. Interestingly, changes in the relative abundances of classes frequently deviated from the responses of the phyla to which they belong. Despite the apparent Cu impacts on Cu resistance and community structure, bioavailable Cu levels did not show any correlation to bacterial OTU richness (97% similarity level). Our report highlights several bacterial taxa responding to Cu and thereby provides new guidelines for future studies aiming to explore the bacterial domain for members of metal-responding taxa.
AB - Toxic metal pollution affects the composition and metal tolerance of soil bacterial communities. However, there is virtually no knowledge concerning the responses of members of specific bacterial taxa (e.g., phyla or classes) to metal toxicity, and contradictory results have been obtained regarding the impact of metals on operational taxonomic unit (OTU) richness. We used tagcoded pyrosequencing of the 16S rRNA gene to elucidate the impacts of copper (Cu) on bacterial community composition and diversity within a well-described Cu gradient (20 to 3,537 μg g-1) stemming from industrial contamination with CuSO4 more than 85 years ago. DNA sequence information was linked to analysis of pollution-induced community tolerance (PICT) to Cu, as determined by the [3H]leucine incorporation technique, and to chemical characterization of the soil. PICT was significantly correlated to bioavailable Cu, as determined by the results seen with a Cu-specific bioluminescent biosensor strain, demonstrating a specific community response to Cu. The relative abundances of members of several phyla or candidate phyla, including the Proteobacteria, Bacteroidetes, Verrumicrobia, Chloroflexi, WS3, and Planctomycetes, decreased with increasing bioavailable Cu, while members of the dominant phylum, the Actinobacteria, showed no response and members of the Acidobacteria showed a marked increase in abundance. Interestingly, changes in the relative abundances of classes frequently deviated from the responses of the phyla to which they belong. Despite the apparent Cu impacts on Cu resistance and community structure, bioavailable Cu levels did not show any correlation to bacterial OTU richness (97% similarity level). Our report highlights several bacterial taxa responding to Cu and thereby provides new guidelines for future studies aiming to explore the bacterial domain for members of metal-responding taxa.
U2 - 10.1128/AEM.01071-12
DO - 10.1128/AEM.01071-12
M3 - Journal article
C2 - 22904046
SN - 0099-2240
VL - 78
SP - 7438
EP - 7446
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
IS - 20
ER -