ena-STUDY-Center of Applied Geosciences-16-12-2014-14:18:30:662-70
Rhizosphere microbial community composition affects cadmium and zinc uptake of the metal-hyperaccumulating plant Arabidopsis halleri
The remediation of metal-contaminated soils by phytoextraction depends on plant growth and plant metal accessibility. Soil microorganisms can affect the accumulation of metals by plants by either directly or indirectly stimulating plant growth and activity or by (im)mobilizing and/or complexing metals. Understanding the intricate interplay of metal-accumulating plants with their rhizosphere microbiome is an important step towards the application and optimization of phytoremediation. We studied the effect of a ‘native’ compared to a strongly disturbed (gamma-irradiated) soil microbial community on cadmium and zinc accumulation by the plant Arabidopsis halleri in soil microcosm experiments. A. halleri accumulated 100% more cadmium and 15% more zinc when grown on the untreated compared to the gamma-irradiated soil. Gamma-irradiation did not affect soil metal bioavailability or plant growth. However, it strongly altered soil microbial community composition and overall cell numbers. Pyrosequencing of 16S rRNA gene amplicons of DNA extracted from rhizosphere samples of A. halleri revealed distinct differences in microbial community richness and evenness between the untreated and gamma-irradiated soil. Classification and comparative sequence analysis allowed the identification of microbial taxa (Lysobacter, Streptomyces, and Agromyces) that might have enhanced the accumulation of Cd and Zn by A. halleri in the microcosms with the untreated soil. We discuss different mechanisms of interaction of A. halleri with its rhizosphere microbiome that might have directly or indirectly affected plant metal accumulation. Deciphering the complex interplay between A. halleri and individual microbial taxa will help to further develop soil metal phytoextraction strategies as efficient and sustainable remediation procedure.
The remediation of metal-contaminated soils by phytoextraction depends on plant growth and plant metal accessibility. Soil microorganisms can affect the accumulation of metals by plants by either directly or indirectly stimulating plant growth and activity or by (im)mobilizing and/or complexing metals. Understanding the intricate interplay of metal-accumulating plants with their rhizosphere microbiome is an important step towards the application and optimization of phytoremediation. We studied the effect of a ‘native’ compared to a strongly disturbed (gamma-irradiated) soil microbial community on cadmium and zinc accumulation by the plant Arabidopsis halleri in soil microcosm experiments. A. halleri accumulated 100% more cadmium and 15% more zinc when grown on the untreated compared to the gamma-irradiated soil. Gamma-irradiation did not affect soil metal bioavailability or plant growth. However, it strongly altered soil microbial community composition and overall cell numbers. Pyrosequencing of 16S rRNA gene amplicons of DNA extracted from rhizosphere samples of A. halleri revealed distinct differences in microbial community richness and evenness between the untreated and gamma-irradiated soil. Classification and comparative sequence analysis allowed the identification of microbial taxa (Lysobacter, Streptomyces, and Agromyces) that might have enhanced the accumulation of Cd and Zn by A. halleri in the microcosms with the untreated soil. We discuss different mechanisms of interaction of A. halleri with its rhizosphere microbiome that might have directly or indirectly affected plant metal accumulation. Deciphering the complex interplay between A. halleri and individual microbial taxa will help to further develop soil metal phytoextraction strategies as efficient and sustainable remediation procedure.