Project Number: 5012-12220-008-09
Start Date: Sep 01, 2011
End Date: Aug 31, 2014
The project is designed for 3 years. Shewanella loihica strain PV4 and Anaeromyxobacter spp. will be used as models to explore the physiological controls and regulatory networks that govern nitrate reduction pathways (e.g., DNRA versus denitrification) and associated C metabolism. Tools for quantitative evaluation of pathway-specific molecular biomarkers (i.e., genes, transcripts, protein) will be designed, tested and applied to assess the prevalence of DNRA vs. denitrification pathways and determine the environmental variables (e.g., C:N ratios, pH, temperature, soil moisture, soil type) that control activity of these pathways. Cultivation-based studies, genetic approaches, tag-encoded pyrosequencing, deep sequencing, metagenomics followed by a metatranscriptome analysis, and proteomic workflows for key biomarkers (e.g., nrfA, nosZ) will be used (U Tennessee, GaTech). N flux and associated C turnover will be quantitatively assessed using mass balance approaches, which will include 13C- and 15N-labeled compounds in mesocosm studies combined with nucleic acid- and protein-targeted approaches (ARS, U Illinois).