Phytoremediation of Nitrous Oxide: Expression of Nitrous Oxide Reductase from Pseudomonas Stutzeri in Transgenic Plants and Activity thereof

Phytoremediation of Nitrous Oxide: Expression of Nitrous Oxide Reductase from Pseudomonas Stutzeri in Transgenic Plants and Activity thereof

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dc.contributor.author Wan, Shen
dc.date.accessioned 2012-02-01T16:38:59Z
dc.date.available 2012-02-01T16:38:59Z
dc.date.created 2012 en_US
dc.date.issued 2012-02-01
dc.identifier.uri http://hdl.handle.net/10393/20661
dc.description.abstract As the third most important greenhouse gas, nitrous oxide (N2O) is a stable greenhouse gas and also plays a significant role in stratospheric ozone destruction. The primary anthropogenic source of N2O stems from the use of nitrogen in agriculture, with soils being the major contributors. Currently, the annual N2O emissions from this “soil–microbe-plant” system is more than 2.6 Tg (one Tg equals a million metric tons) of N2O-N globally. My doctoral studies aimed to explore innovative strategies for N2O mitigation, in the context of environmental microbiology’s potential contribution to alleviating global warming. The bacterial enzyme nitrous oxide reductase (N2OR), naturally found in some soils, is the only known enzyme capable of catalyzing the final step of the denitrification pathway, conversion of N2O to N2. Therefore, to “scrub” or reduce N2O emissions, bacterial N2OR was heterologously expressed inside the leaves and roots of transgenic plants. Others had previously shown that the functional assembly of the catalytic centres (CuZ) of N2OR is lacking when only nosZ is expressed in other bacterial hosts. There, coexpression of nosZ with nosD, nosF and nosY was found to be necessary for production of the catalytically active holoenzyme. I have generated transgenic tobacco plants expressing the nosZ gene, as well as tobacco plants in which the other four nos genes were coexpressed. More than 100 transgenic tobacco lines, expressing nosZ and nosFLZDY under the control of rolD promoter and d35S promoter, have been analyzed by PCR, RT-PCR and Western blot. The activity of N2OR expressed in transgenic plants, analyzed with the methyl viologen-linked enzyme assay, showed detectable N2O reducing activity. The N2O-reducing patterns observed were similar to that of the positive control purified bacterial N2OR. The data indicated that expressing bacterial N2OR heterologously in plants, without the expression of the accessory Nos proteins, could convert N2O into inert N2. This suggests that atmospheric phytoremediation of N2O by plants harbouring N2OR could be invaluable in efforts to reduce emissions from crop production fields. en_US
dc.language.iso en en_US
dc.subject Greenhouse gas en_US
dc.subject Nitrous oxide en_US
dc.subject Nitrous oxide reductase en_US
dc.subject Phytoremediation en_US
dc.subject Transgenic plants en_US
dc.subject GMO crops en_US
dc.subject Global warming en_US
dc.subject Climate change en_US
dc.title Phytoremediation of Nitrous Oxide: Expression of Nitrous Oxide Reductase from Pseudomonas Stutzeri in Transgenic Plants and Activity thereof en_US
dc.type Thèse / Thesis en_US
dc.faculty.department Biochimie, microbiologie et immunologie / Biochemistry, Microbiology and Immunology en_US
dc.contributor.supervisor Altosaar, Ilimar
dc.embargo.terms immediate en_US
dc.degree.name PhD en_US
dc.degree.level doctorate en_US
dc.degree.discipline Médecine / Medicine en_US

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