Potential of the TCE-degrading endophyte Pseudomonas putida W619-TCE to improve plant growth and reduce TCE phytotoxicity and evapotranspiration in poplar cuttings.
ABSTRACT The TCE-degrading poplar endophyte Pseudomonas putida W619-TCE was inoculated in poplar cuttings, exposed to 0, 200 and 400 mg l(-1) TCE, that were grown in two different experimental setups. During a short-term experiment, plants were grown hydroponically in half strength Hoagland nutrient solution and exposed to TCE for 3 days. Inoculation with P. putida W619-TCE promoted plant growth, reduced TCE phytotoxicity and reduced the amount of TCE present in the leaves. During a mid-term experiment, plants were grown in potting soil and exposed to TCE for 3 weeks. Here, inoculation with P. putida W619-TCE had a less pronounced positive effect on plant growth and TCE phytotoxicity, but resulted in strongly reduced amounts of TCE in leaves and roots of plants exposed to 400 mg l(-1) TCE, accompanied by a lowered evapotranspiration of TCE. Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), which are known intermediates of TCE degradation, were not detected.
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ABSTRACT: Recently, there has been an increased effort to enhance the efficacy of phytoremediation of contaminated environments by exploiting plant-microbe interactions. The combined use of plants and endophytic bacteria is an emerging approach for the clean-up of soil and water polluted with organic compounds. In plant-endophyte partnerships, plants provide the habitat as well as nutrients to their associated endophytic bacteria. In response, endophytic bacteria with appropriate degradation pathways and metabolic activities enhance degradation of organic pollutants, and diminish phytotoxicity and evapotranspiration of organic pollutants. Moreover, endophytic bacteria possessing plant growth-promoting activities enhance the plant's adaptation and growth in soil and water contaminated with organic pollutants. Overall, the application of endophytic bacteria gives new insights into novel protocols to improve phytoremediation efficiency. However, successful application of plant-endophyte partnerships for the clean-up of an environment contaminated with organic compounds depends on the abundance and activity of the degrading endophyte in different plant compartments. Although many endophytic bacteria have the potential to degrade organic pollutants and improve plant growth, their contribution to enhance phytoremediation efficiency is still underestimated. A better knowledge of plant-endophyte interactions could be utilized to increase the remediation of polluted soil environments and to protect the foodstuff by decreasing agrochemical residues in food crops.Chemosphere 07/2014; 117C:232-242. · 3.14 Impact Factor
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ABSTRACT: Endophytes have been isolated from a large diversity of plants and have shown to enhance the remediation efficiency of plants, but little information is available on the influence of endophytic bacteria on phytoremediation of widespread environmental contaminants such as polyaromatic hydrocarbons (PAHs). In this study we selected a naturally occurring endophyte for its combined ability to colonize plant roots and degrade phenanthrene in vitro. Inoculation of two different willow clones and a grass with Pseudomonas putida PD1 was found to promote root and shoot growth and protect the plants against the phytotoxic effects of phenanthrene. In addition there was 25-40% removal of phenanthrene from soil by the willow and grasses inoculated with PD1 when compared to the uninoculated controls. Epifluorescent microscopy using fluorescent protein tagging of PD1 confirmed the presence of bacteria inside the root tissue. Inoculation of willows with PD1 consistently improved the growth and health when grown in hydroponic systems with high concentrations of phenanthrene. To our knowledge this is the first time that the inoculation of willow plants has been shown to improve the degradation of PAHs and improve the health of the host plants, demonstrating the potential wide benefit to the field of natural endophyte-assisted phytoremediation.Environmental science & technology. 10/2014;