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Whole Cell Bacterial Biosensor for Glutamine and Applications to Plants and Microbes

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dc.contributor.advisor Raizada, Manish Tessaro, Michael 2012-01-09 2012-02-03T19:15:08Z 2012-02-03T19:15:08Z 2012-02-03
dc.description.abstract Glutamine (Gln) is a critical intermediate in nitrogen metabolism in all organisms. Here, a whole cell biosensor (GlnLux) for Gln was constructed by transforming a bacterial Gln auxotroph with a constitutive lux reporter. The biosensor was optimized for sensitivity, linearity, efficiency, specificity and robustness to permit detection of Gln in vitro and in vivo. The optimized GlnLux biosensor achieved nanomolar sensitivity with Gln standards. Extracts from only 1 mg of maize (Zea mays L.) leaf tissue were sufficient for Gln detection by GlnLux. Measurements of Gln in leaf extracts by GlnLux correlated with quantification by high performance liquid chromatography (Spearman r = 0.95). GlnLux permitted indirect in planta imaging of Gln using a CCD camera, enabling identification of plants that had been fertilized with nitrogen. Imaging using GlnLux also resolved predicted spatial differences in leaf Gln concentration. In a second application, it was demonstrated that GlnLux embedded into agar permits non-destructive screening of co-inoculated bacterial colonies for biological nitrogen fixation (BNF). GlnLux agar was able to distinguish a Bradyrhizobium japonicum wild type strain (nif+) from a mutant strain defective in nitrogenase (nif-) following ≥8 h of co-incubation. The technology was used to screen a bacterial endophyte diversity library cultured from Zea mays (L.) seeds for biological nitrogen fixation. en_US
dc.description.sponsorship OMAFRA en_US
dc.language.iso en en_US
dc.rights.uri *
dc.subject Biosensor en_US
dc.subject Glutamine en_US
dc.subject Plant Nitrogen Status en_US
dc.subject Biological Nitrogen Fixation en_US
dc.subject Whole-cell biosensor en_US
dc.title Whole Cell Bacterial Biosensor for Glutamine and Applications to Plants and Microbes en_US
dc.type Thesis en_US Plant Agriculture en_US Master of Science en_US Department of Plant Agriculture en_US

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