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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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Schematic representation of how bacteria containing ACC deaminase activity lower the ethylene concentration and thereby prevent ethylene-caused inhibition of root elongation.
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pone-0111208-g002: Schematic representation of how bacteria containing ACC deaminase activity lower the ethylene concentration and thereby prevent ethylene-caused inhibition of root elongation.

Mentions: In this study, diesel contamination in soil reduced plant growth and development. It is well established that the presence of hydrocarbons adversely affects plant health and development due to their toxicity and hydrophobicity [4], [29]. However, when bacterial strain, Pantoea sp. BTRH79, was inoculated in diesel contaminated soil, it enhanced plant growth and development. Enhanced plant growth and development might be attributed to plant growth promoting activities (including ACC deaminase) of the inoculated bacterium [20], [21], [27]. In principle, bacterial ACC deaminase activity reduces the contaminant induced stress symptoms in developing plant and improves plant health and growth in the presence of contaminants as shown in Fig. 2[30]–[32]. Similarly, hydrocarbon-degrading activity of the inoculated microorganisms reduces the phytotoxicity of pollutants due to their potential to produce hydrocarbon-degrading enzymes [33]. Plant growth was further enhanced by the application of nutrients. Earlier studies also reported that the application of nutrients improved plant growth and development during remediation of polluted soil [18], [34].


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)

Schematic representation of how bacteria containing ACC deaminase activity lower the ethylene concentration and thereby prevent ethylene-caused inhibition of root elongation.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0111208-g002: Schematic representation of how bacteria containing ACC deaminase activity lower the ethylene concentration and thereby prevent ethylene-caused inhibition of root elongation.
Mentions: In this study, diesel contamination in soil reduced plant growth and development. It is well established that the presence of hydrocarbons adversely affects plant health and development due to their toxicity and hydrophobicity [4], [29]. However, when bacterial strain, Pantoea sp. BTRH79, was inoculated in diesel contaminated soil, it enhanced plant growth and development. Enhanced plant growth and development might be attributed to plant growth promoting activities (including ACC deaminase) of the inoculated bacterium [20], [21], [27]. In principle, bacterial ACC deaminase activity reduces the contaminant induced stress symptoms in developing plant and improves plant health and growth in the presence of contaminants as shown in Fig. 2[30]–[32]. Similarly, hydrocarbon-degrading activity of the inoculated microorganisms reduces the phytotoxicity of pollutants due to their potential to produce hydrocarbon-degrading enzymes [33]. Plant growth was further enhanced by the application of nutrients. Earlier studies also reported that the application of nutrients improved plant growth and development during remediation of polluted soil [18], [34].

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