Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil
Reduced bioavailability to soil microorganisms is probably the most limiting factor in the bioremediation of polycyclic aromatic hydrocarbons PAH-polluted soils. We used sunflowers planted in pots containing soil to determine the influence of the rhizosphere on the ability of soil microbiota to reduce PAH levels. The concentration of total PAHs decreased by 93% in 90 days when the contaminated soil was cultivated with sunflowers, representing an improvement of 16% compared to contaminated soil without plants. This greater extent of PAH degradation was consistent with the positive effect of the rhizosphere in selectively stimulating the growth of PAH-degrading populations. Molecular analysis revealed that the increase in the number of degraders was accompanied by a dramatic shift in the structure of the bacterial soil community favoring groups with a well-known PAH-degrading capacity, such as Sphingomonas (α-Proteobacteria), Commamonas and Oxalobacteria (β-Proteobacteria), and Xhanthomonas (γ-Proteobacteria). Other groups that were promoted for which degrading activity has not been reported included Methylophyllus (β-Proteobacteria) and the recently described phyla Acidobacteria and Gemmatimonadetes. We also conducted mineralization experiments on creosote-polluted soil in the presence and absence of sunflower root exudates to advance our understanding of the ability of these exudates to serve as bio-stimulants in the degradation of PAHs. By conducting greenhouse and mineralization experiments, we separated the chemical impact of the root exudates from any root surface phenomena, as sorption of contaminants to the roots, indicating that sunflower root exudates have the potential to increase the degradation of xenobiotics due to its influence on the soil microorganisms, where sunflower root exudates act improving the availability of the contaminant to be degraded. We characterized the sunflower exudates in vitro to determine the total organic carbon (TOC) and its chemical composition. Our results indicate that the rhizosphere promotes the degradation of PAHs by increasing the biodegradation of the pollutants and the number and diversity of PAH degraders. We propose that the biostimulation exerted by the plants is based on the chemical composition of the exudates.
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Pergamon Press
2013-02
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Subjects: | Rhizosphere, Microbial community structure, Bioremediation, PAHs, Sunflower root exudates, Biodegradation, |
Online Access: | http://hdl.handle.net/10261/80136 |
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dig-irnas-es-10261-801362018-09-13T08:29:56Z Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil Tejeda Agredano, M. C. Gallego, Sara Vila, Joaquim Ortega Calvo, J. J. Cantos, Manuel Rhizosphere Microbial community structure Bioremediation PAHs Sunflower root exudates Biodegradation Reduced bioavailability to soil microorganisms is probably the most limiting factor in the bioremediation of polycyclic aromatic hydrocarbons PAH-polluted soils. We used sunflowers planted in pots containing soil to determine the influence of the rhizosphere on the ability of soil microbiota to reduce PAH levels. The concentration of total PAHs decreased by 93% in 90 days when the contaminated soil was cultivated with sunflowers, representing an improvement of 16% compared to contaminated soil without plants. This greater extent of PAH degradation was consistent with the positive effect of the rhizosphere in selectively stimulating the growth of PAH-degrading populations. Molecular analysis revealed that the increase in the number of degraders was accompanied by a dramatic shift in the structure of the bacterial soil community favoring groups with a well-known PAH-degrading capacity, such as Sphingomonas (α-Proteobacteria), Commamonas and Oxalobacteria (β-Proteobacteria), and Xhanthomonas (γ-Proteobacteria). Other groups that were promoted for which degrading activity has not been reported included Methylophyllus (β-Proteobacteria) and the recently described phyla Acidobacteria and Gemmatimonadetes. We also conducted mineralization experiments on creosote-polluted soil in the presence and absence of sunflower root exudates to advance our understanding of the ability of these exudates to serve as bio-stimulants in the degradation of PAHs. By conducting greenhouse and mineralization experiments, we separated the chemical impact of the root exudates from any root surface phenomena, as sorption of contaminants to the roots, indicating that sunflower root exudates have the potential to increase the degradation of xenobiotics due to its influence on the soil microorganisms, where sunflower root exudates act improving the availability of the contaminant to be degraded. We characterized the sunflower exudates in vitro to determine the total organic carbon (TOC) and its chemical composition. Our results indicate that the rhizosphere promotes the degradation of PAHs by increasing the biodegradation of the pollutants and the number and diversity of PAH degraders. We propose that the biostimulation exerted by the plants is based on the chemical composition of the exudates. Support for this research was provided by the Spanish Ministry of the Economy and Competitiveness (grants CGL2007-64199, CGL2010-22068-C02-01 and CGL2010-22068-C02-02). Peer Reviewed 2013-07-24T10:57:53Z 2013-07-24T10:57:53Z 2013-02 2013-07-24T10:57:53Z artículo http://purl.org/coar/resource_type/c_6501 issn: 0038-0717 Soil Biology and Biochemistry 57: 830-840 (2013) http://hdl.handle.net/10261/80136 10.1016/j.soilbio.2012.08.008 en http://dx.doi.org/10.1016/j.soilbio.2012.08.008 open Pergamon Press |
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Rhizosphere Microbial community structure Bioremediation PAHs Sunflower root exudates Biodegradation Rhizosphere Microbial community structure Bioremediation PAHs Sunflower root exudates Biodegradation |
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Rhizosphere Microbial community structure Bioremediation PAHs Sunflower root exudates Biodegradation Rhizosphere Microbial community structure Bioremediation PAHs Sunflower root exudates Biodegradation Tejeda Agredano, M. C. Gallego, Sara Vila, Joaquim Ortega Calvo, J. J. Cantos, Manuel Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil |
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Reduced bioavailability to soil microorganisms is probably the most limiting factor in the bioremediation of polycyclic aromatic hydrocarbons PAH-polluted soils. We used sunflowers planted in pots containing soil to determine the influence of the rhizosphere on the ability of soil microbiota to reduce PAH levels. The concentration of total PAHs decreased by 93% in 90 days when the contaminated soil was cultivated with sunflowers, representing an improvement of 16% compared to contaminated soil without plants. This greater extent of PAH degradation was consistent with the positive effect of the rhizosphere in selectively stimulating the growth of PAH-degrading populations. Molecular analysis revealed that the increase in the number of degraders was accompanied by a dramatic shift in the structure of the bacterial soil community favoring groups with a well-known PAH-degrading capacity, such as Sphingomonas (α-Proteobacteria), Commamonas and Oxalobacteria (β-Proteobacteria), and Xhanthomonas (γ-Proteobacteria). Other groups that were promoted for which degrading activity has not been reported included Methylophyllus (β-Proteobacteria) and the recently described phyla Acidobacteria and Gemmatimonadetes. We also conducted mineralization experiments on creosote-polluted soil in the presence and absence of sunflower root exudates to advance our understanding of the ability of these exudates to serve as bio-stimulants in the degradation of PAHs. By conducting greenhouse and mineralization experiments, we separated the chemical impact of the root exudates from any root surface phenomena, as sorption of contaminants to the roots, indicating that sunflower root exudates have the potential to increase the degradation of xenobiotics due to its influence on the soil microorganisms, where sunflower root exudates act improving the availability of the contaminant to be degraded. We characterized the sunflower exudates in vitro to determine the total organic carbon (TOC) and its chemical composition. Our results indicate that the rhizosphere promotes the degradation of PAHs by increasing the biodegradation of the pollutants and the number and diversity of PAH degraders. We propose that the biostimulation exerted by the plants is based on the chemical composition of the exudates. |
format |
artículo |
topic_facet |
Rhizosphere Microbial community structure Bioremediation PAHs Sunflower root exudates Biodegradation |
author |
Tejeda Agredano, M. C. Gallego, Sara Vila, Joaquim Ortega Calvo, J. J. Cantos, Manuel |
author_facet |
Tejeda Agredano, M. C. Gallego, Sara Vila, Joaquim Ortega Calvo, J. J. Cantos, Manuel |
author_sort |
Tejeda Agredano, M. C. |
title |
Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil |
title_short |
Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil |
title_full |
Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil |
title_fullStr |
Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil |
title_full_unstemmed |
Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil |
title_sort |
influence of the sunflower rhizosphere on the biodegradation of pahs in soil |
publisher |
Pergamon Press |
publishDate |
2013-02 |
url |
http://hdl.handle.net/10261/80136 |
work_keys_str_mv |
AT tejedaagredanomc influenceofthesunflowerrhizosphereonthebiodegradationofpahsinsoil AT gallegosara influenceofthesunflowerrhizosphereonthebiodegradationofpahsinsoil AT vilajoaquim influenceofthesunflowerrhizosphereonthebiodegradationofpahsinsoil AT ortegacalvojj influenceofthesunflowerrhizosphereonthebiodegradationofpahsinsoil AT cantosmanuel influenceofthesunflowerrhizosphereonthebiodegradationofpahsinsoil |
_version_ |
1777664628086538240 |