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Soil communities associated with specific plant species affect individual plants' growth and competitive ability. Limited evidence suggests that unique soil communities can also differentially influence growth and competition at the ecotype level. Previous work with Arabidopsis thaliana has shown that accessions produce distinct and reproducible rhizosphere bacterial communities, with significant differences in both species composition and relative abundance. We tested the hypothesis that soil communities uniquely affect the growth and reproduction of the plant accessions with which they are associated. Specifically, we examined the growth of four accessions when exposed to their own soil communities and the communities generated by each of the other three accessions. To do this we planted focal accessions inside a ring of six plants that created a “background” soil community. We grew focal plants in this design in three separate soil treatments: non-sterile soil, sterilized soil, and “preconditioned” soil. We preconditioned soil by growing accessions in non-sterile soil for six weeks before the start of the experiment. The main experiment was harvested after seven weeks of growth and we recorded height, silique number, and dry weight of each focal plant. Plants grown in the preconditioned soil treatment showed less growth relative to the non-sterile and sterile soil treatments. In addition, plants in the sterile soil grew larger than those in non-sterile soil. However, we saw no interaction between soil treatment and background accession. We conclude that the soil communities have a negative net impact on Arabidopsis thaliana growth, and that the unique soil communities associated with each accession do not differentially affect growth and competition of study species.


Originally published in the open access journal PLoS ONE:

This work was supported by the U.S. National Science Foundation, through a Graduate Research Fellowship to AGA and through grant IOS-0847691 to RK, JSD, ACC, and M. Shiaris. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


Public Library of Science (PLoS)


© 2011 Aguilera et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.



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