Abstract
Background: Plants selectively attract particular soil microorganisms, in particular consumers of root-excreted compounds.
It is unclear to what extent cultivar type and/or growth stage affect this process.
Methodology/Principal Findings: DNA-based pyrosequencing was used to characterize the structure of bacterial
communities in a field cropped with potato. The rhizospheres of six cultivars denoted Aveka, Aventra, Karnico, Modena,
Premiere and Desiree, at three growth stages (young, flowering and senescence) were examined, in addition to
corresponding bulk soils. Around 350,000 sequences were obtained (5,700 to 38,000 per sample). Across all samples, rank
abundance distributions best fitted the power law model, which indicates a community composed of a few highly
dominant species next to numerous rare species. Grouping of the sequences showed that members of the Actinobacteria,
Alphaproteobacteria, next to as-yet-unclassified bacteria, dominated. Other groups that were consistently found, albeit at
lower abundance, were Beta-, Gamma- and Deltaproteobacteria and Acidobacteria. Principal components analyses revealed
that rhizosphere samples were significantly different from corresponding bulk soil in each growth stage. Furthermore,
cultivar effects were found in the young plant stage, whereas these became insignificant in the flowering and senescence
stages. Besides, an effect of time of season was observed for both rhizosphere and bulk soils. The analyzed rhizosphere
samples of the potato cultivars were grouped into two groups, in accordance with the allocation of carbon to starch in their
tubers, i.e. Aveka, Aventra and Karnico (high) versus Premiere and Desiree (low) and thus replicates per group were
established.
Conclusions: Across all potato cultivars, the young plant stages revealed cultivar-dependent bacterial community
structures, which disappeared in the flowering and senescence stages. Furthermore, Pseudomonas, Beta-, Alpha- and
Deltaproteobacteria flourished under different ecological conditions than the Acidobacteria.
It is unclear to what extent cultivar type and/or growth stage affect this process.
Methodology/Principal Findings: DNA-based pyrosequencing was used to characterize the structure of bacterial
communities in a field cropped with potato. The rhizospheres of six cultivars denoted Aveka, Aventra, Karnico, Modena,
Premiere and Desiree, at three growth stages (young, flowering and senescence) were examined, in addition to
corresponding bulk soils. Around 350,000 sequences were obtained (5,700 to 38,000 per sample). Across all samples, rank
abundance distributions best fitted the power law model, which indicates a community composed of a few highly
dominant species next to numerous rare species. Grouping of the sequences showed that members of the Actinobacteria,
Alphaproteobacteria, next to as-yet-unclassified bacteria, dominated. Other groups that were consistently found, albeit at
lower abundance, were Beta-, Gamma- and Deltaproteobacteria and Acidobacteria. Principal components analyses revealed
that rhizosphere samples were significantly different from corresponding bulk soil in each growth stage. Furthermore,
cultivar effects were found in the young plant stage, whereas these became insignificant in the flowering and senescence
stages. Besides, an effect of time of season was observed for both rhizosphere and bulk soils. The analyzed rhizosphere
samples of the potato cultivars were grouped into two groups, in accordance with the allocation of carbon to starch in their
tubers, i.e. Aveka, Aventra and Karnico (high) versus Premiere and Desiree (low) and thus replicates per group were
established.
Conclusions: Across all potato cultivars, the young plant stages revealed cultivar-dependent bacterial community
structures, which disappeared in the flowering and senescence stages. Furthermore, Pseudomonas, Beta-, Alpha- and
Deltaproteobacteria flourished under different ecological conditions than the Acidobacteria.
| Original language | English |
|---|---|
| Journal | P L o S One |
| Volume | 6 |
| Issue number | 8 |
| Pages (from-to) | e23321 (1-10) |
| Number of pages | 11 |
| ISSN | 1932-6203 |
| DOIs | |
| Publication status | Published - 1 Aug 2011 |