This Article Full Text Full Text (PDF) Supplemental material Other Versions of this Article: AEM.01533-07v1 73/21/6916    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zul, D. Articles by Overmann, J. Search for Related Content PubMed PubMed Citation Articles by Zul, D. Articles by Overmann, J. Agricola Articles by Zul, D. Articles by Overmann, J.

Effects of Plant Biomass, Plant Diversity, and Water Content on Bacterial Communities in Soil Lysimeters: Implications for the Determinants of Bacterial Diversity ^,

Delita Zul, Sabine Denzel, Andrea Kotz, and Jörg Overmann^*

Bereich Mikrobiologie, Department Biologie I, Ludwig-Maximilians-Universität München, Maria-Ward-Str. 1a, D-80638 München, Germany

Received 6 July 2007/ Accepted 7 September 2007

Soils may comprise tens of thousands to millions of bacterial species. It is still unclear whether this high level of diversity is governed by functional redundancy or by a multitude of ecological niches. In order to address this question, we analyzed the reproducibility of bacterial community composition after different experimental manipulations. Soil lysimeters were planted with four different types of plant communities, and the water content was adjusted. Group-specific phylogenetic fingerprinting by PCR-denaturing gradient gel electrophoresis revealed clear differences in the composition of Alphaproteobacteria, Betaproteobacteria, Bacteroidetes, Chloroflexi, Planctomycetes, and Verrucomicrobia populations in soils without plants compared to that of populations in planted soils, whereas no influence of plant species composition on bacterial diversity could be discerned. These results indicate that the presence of higher plant species affects the species composition of bacterial groups in a reproducible manner and even outside of the rhizosphere. In contrast, the environmental factors tested did not affect the composition of Acidobacteria, Actinobacteria, Archaea, and Firmicutes populations. One-third (52 out of 160) of the sequence types were found to be specifically and reproducibly associated with the absence or presence of plants. Unexpectedly, this was also true for numerous minor constituents of the soil bacterial assemblage. Subsequently, one of the low-abundance phylotypes (beta10) was selected for studying the interdependence under particular experimental conditions and the underlying causes in more detail. This so-far-uncultured phylotype of the Betaproteobacteria species represented up to 0.18% of all bacterial cells in planted lysimeters compared to 0.017% in unplanted systems. A cultured representative of this phylotype exhibited high physiological flexibility and was capable of utilizing major constituents of root exudates. Our results suggest that the bacterial species composition in soil is determined to a significant extent by abiotic and biotic factors, rather than by mere chance, thereby reflecting a multitude of distinct ecological niches.

Published ahead of print on 14 September 2007.

Supplemental material for this article may be found at http://aem.asm.org/.

Present address: GSF-Research Center for Health and Environment, Marchioninistr. 15, D-81377 München, Germany.

Present address: Max-von-Pettenkofer-Institut, Ludwig-Maximilians-Universität, Pettenkoferstr. 9a, D-80336 München, Germany.

This article has been cited by other articles:

• Koch, I. H., Gich, F., Dunfield, P. F., Overmann, J. (2008). Edaphobacter modestus gen. nov., sp. nov., and Edaphobacter aggregans sp. nov., acidobacteria isolated from alpine and forest soils. Int. J. Syst. Evol. Microbiol. 58: 1114-1122 [Abstract] [Full Text]  
• Zul, D., Wanner, G., Overmann, J. (2008). Massilia brevitalea sp. nov., a novel betaproteobacterium isolated from lysimeter soil. Int. J. Syst. Evol. Microbiol. 58: 1245-1251 [Abstract] [Full Text]