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Nutrients can enhance the abundance and expression of alkane hydroxylase CYP153 gene in the rhizosphere of ryegrass planted in hydrocarbon-polluted soil.

Arslan M, Afzal M, Amin I, Iqbal S, Khan QM - PLoS ONE (2014)

Bottom Line: Results obtained from these experiments showed that the bacterial inoculation improved plant growth and hydrocarbon degradation and these were further enhanced by nutrients application.The abundance and expression of CYP153 gene in the rhizosphere of ryegrass was found to be directly associated with the level of applied nutrients.It is thus concluded that the combination between vegetation, inoculation with pollutant-degrading bacteria and nutrients amendment was an efficient approach to reduce hydrocarbon contamination.

View Article: PubMed Central - PubMed

Affiliation: Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan; Earth Sciences Department, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia.

ABSTRACT
Plant-bacteria partnership is a promising strategy for the remediation of soil and water polluted with hydrocarbons. However, the limitation of major nutrients (N, P and K) in soil affects the survival and metabolic activity of plant associated bacteria. The objective of this study was to explore the effects of nutrients on survival and metabolic activity of an alkane degrading rhizo-bacterium. Annual ryegrass (Lolium multiflorum) was grown in diesel-contaminated soil and inoculated with an alkane degrading bacterium, Pantoea sp. strain BTRH79, in greenhouse experiments. Two levels of nutrients were applied and plant growth, hydrocarbon removal, and gene abundance and expression were determined after 100 days of sowing of ryegrass. Results obtained from these experiments showed that the bacterial inoculation improved plant growth and hydrocarbon degradation and these were further enhanced by nutrients application. Maximum plant biomass production and hydrocarbon mineralization was observed by the combined use of inoculum and higher level of nutrients. The presence of nutrients in soil enhanced the colonization and metabolic activity of the inoculated bacterium in the rhizosphere. The abundance and expression of CYP153 gene in the rhizosphere of ryegrass was found to be directly associated with the level of applied nutrients. Enhanced hydrocarbon degradation was associated with the population of the inoculum bacterium, the abundance and expression of CYP153 gene in the rhizosphere of ryegrass. It is thus concluded that the combination between vegetation, inoculation with pollutant-degrading bacteria and nutrients amendment was an efficient approach to reduce hydrocarbon contamination.

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Experimental setup illustrating different treatments.Ryegrass vegetated in uncontaminated soil (A), ryegrass vegetated in uncontaminated soil and inoculated with Pantoea sp. strain BTRH79 (B), inoculation of Pantoea sp. strain BTRH79 in diesel contaminated soil (C), ryegrass vegetated in diesel contaminated soil (D), ryegrass vegetated in diesel contaminated soil and inoculated with Pantoea sp. strain BTRH79 (E), ryegrass vegetated in diesel contaminated soil treated with lower level of fertilize and inoculated with Pantoea sp. strain BTRH79 (F), and ryegrass vegetated in diesel contaminated soil treated with higher level of fertilizer and inoculated with Pantoea sp. strain BTRH79 (G).
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pone-0111208-g001: Experimental setup illustrating different treatments.Ryegrass vegetated in uncontaminated soil (A), ryegrass vegetated in uncontaminated soil and inoculated with Pantoea sp. strain BTRH79 (B), inoculation of Pantoea sp. strain BTRH79 in diesel contaminated soil (C), ryegrass vegetated in diesel contaminated soil (D), ryegrass vegetated in diesel contaminated soil and inoculated with Pantoea sp. strain BTRH79 (E), ryegrass vegetated in diesel contaminated soil treated with lower level of fertilize and inoculated with Pantoea sp. strain BTRH79 (F), and ryegrass vegetated in diesel contaminated soil treated with higher level of fertilizer and inoculated with Pantoea sp. strain BTRH79 (G).

Mentions: Growth parameters (root fresh and dry biomass, shoot fresh and dry biomass, average shoot length, average shoot diameter and shoot network length) were estimated to assess the influence of nutrients and bacterial application on plant growth and biomass production (Tables 1 and 2, Fig. 1). In polluted soil, plants showed significantly less growth and biomass production than the plants vegetated in uncontaminated soil. However, bacterial inoculation and nutrients application enhanced plant growth and biomass production. Maximum plant growth and biomass production were obtained when inoculum was applied in the soil containing high concentration of nutrients. Bacterial inoculum in uncontaminated soil improved plant growth but not significantly.


Nutrients can enhance the abundance and expression of alkane hydroxylase CYP153 gene in the rhizosphere of ryegrass planted in hydrocarbon-polluted soil.

Arslan M, Afzal M, Amin I, Iqbal S, Khan QM - PLoS ONE (2014)

Experimental setup illustrating different treatments.Ryegrass vegetated in uncontaminated soil (A), ryegrass vegetated in uncontaminated soil and inoculated with Pantoea sp. strain BTRH79 (B), inoculation of Pantoea sp. strain BTRH79 in diesel contaminated soil (C), ryegrass vegetated in diesel contaminated soil (D), ryegrass vegetated in diesel contaminated soil and inoculated with Pantoea sp. strain BTRH79 (E), ryegrass vegetated in diesel contaminated soil treated with lower level of fertilize and inoculated with Pantoea sp. strain BTRH79 (F), and ryegrass vegetated in diesel contaminated soil treated with higher level of fertilizer and inoculated with Pantoea sp. strain BTRH79 (G).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215983&req=5

pone-0111208-g001: Experimental setup illustrating different treatments.Ryegrass vegetated in uncontaminated soil (A), ryegrass vegetated in uncontaminated soil and inoculated with Pantoea sp. strain BTRH79 (B), inoculation of Pantoea sp. strain BTRH79 in diesel contaminated soil (C), ryegrass vegetated in diesel contaminated soil (D), ryegrass vegetated in diesel contaminated soil and inoculated with Pantoea sp. strain BTRH79 (E), ryegrass vegetated in diesel contaminated soil treated with lower level of fertilize and inoculated with Pantoea sp. strain BTRH79 (F), and ryegrass vegetated in diesel contaminated soil treated with higher level of fertilizer and inoculated with Pantoea sp. strain BTRH79 (G).
Mentions: Growth parameters (root fresh and dry biomass, shoot fresh and dry biomass, average shoot length, average shoot diameter and shoot network length) were estimated to assess the influence of nutrients and bacterial application on plant growth and biomass production (Tables 1 and 2, Fig. 1). In polluted soil, plants showed significantly less growth and biomass production than the plants vegetated in uncontaminated soil. However, bacterial inoculation and nutrients application enhanced plant growth and biomass production. Maximum plant growth and biomass production were obtained when inoculum was applied in the soil containing high concentration of nutrients. Bacterial inoculum in uncontaminated soil improved plant growth but not significantly.

Bottom Line: Results obtained from these experiments showed that the bacterial inoculation improved plant growth and hydrocarbon degradation and these were further enhanced by nutrients application.The abundance and expression of CYP153 gene in the rhizosphere of ryegrass was found to be directly associated with the level of applied nutrients.It is thus concluded that the combination between vegetation, inoculation with pollutant-degrading bacteria and nutrients amendment was an efficient approach to reduce hydrocarbon contamination.

View Article: PubMed Central - PubMed

Affiliation: Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan; Earth Sciences Department, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia.

ABSTRACT
Plant-bacteria partnership is a promising strategy for the remediation of soil and water polluted with hydrocarbons. However, the limitation of major nutrients (N, P and K) in soil affects the survival and metabolic activity of plant associated bacteria. The objective of this study was to explore the effects of nutrients on survival and metabolic activity of an alkane degrading rhizo-bacterium. Annual ryegrass (Lolium multiflorum) was grown in diesel-contaminated soil and inoculated with an alkane degrading bacterium, Pantoea sp. strain BTRH79, in greenhouse experiments. Two levels of nutrients were applied and plant growth, hydrocarbon removal, and gene abundance and expression were determined after 100 days of sowing of ryegrass. Results obtained from these experiments showed that the bacterial inoculation improved plant growth and hydrocarbon degradation and these were further enhanced by nutrients application. Maximum plant biomass production and hydrocarbon mineralization was observed by the combined use of inoculum and higher level of nutrients. The presence of nutrients in soil enhanced the colonization and metabolic activity of the inoculated bacterium in the rhizosphere. The abundance and expression of CYP153 gene in the rhizosphere of ryegrass was found to be directly associated with the level of applied nutrients. Enhanced hydrocarbon degradation was associated with the population of the inoculum bacterium, the abundance and expression of CYP153 gene in the rhizosphere of ryegrass. It is thus concluded that the combination between vegetation, inoculation with pollutant-degrading bacteria and nutrients amendment was an efficient approach to reduce hydrocarbon contamination.

Show MeSH
Related in: MedlinePlus