Project description:Model endophyte Azoarcus sp. BH72 is known to contribute fixed nitrogen to its host Kallar grass by nitrogen fixation and also expresses nitrogenase genes endophytically in rice seedlings in gnotobiotic culture. Availability of fixed nitrogen is one of the important signals regulating the transcription of nitrogenase genes and hence nitrogen fixing activity. Therefore, we analysed global transcription in response to differences in the nitrogen source. Transcription profiles of cells grown microaerobically (0.6% oxygen) on minimal medium with nitrogen (N2-fixing) versus ammonium (combined nitrogen) were compared using a genome-wide microarray approach and differences in the gene expression profile were monitored.
Project description:Model endophyte Azoarcus sp. BH72 is known to contribute fixed nitrogen to its host Kallar grass by nitrogen fixation and also expresses nitrogenase genes endophytically in rice seedlings in gnotobiotic culture. Availability of fixed nitrogen is one of the important signals regulating the transcription of nitrogenase genes and hence nitrogen fixing activity. Therefore, we analysed global transcription in response to differences in the nitrogen source. Transcription profiles of cells grown microaerobically (0.6% oxygen) on minimal medium with nitrogen (N2-fixing) versus ammonium (combined nitrogen) were compared using a genome-wide microarray approach and differences in the gene expression profile were monitored. RNA from cells grown on nitrogen-free synthetic medium under nitrogen fixation (experiment) and combined nitrogen source as ammonium chloride (control) was used for two-color whole-genome microarray approach.
Project description:In this study we show the transcriptional analysis after shifting the Ustilago maydis from media with ammonium as a nitrogen source to media lacking ammonium. From these, 49 genes were up-regulated and 41 were down-regulated. The functional description and gene ontology terms associated to the diferentially expressed genes revealed that various key pathways were represented, including, secondary metabolism, the metabolism of nitrogen, amino acid, fatty acid and amino sugar, among others, suggesting that the interplay of U. maydis with its N2 fixing bacterial endosymbiont is a flexible process that may be active during the adaptation to the fungus to the different nitrogen sources, and possibly during its pathogenic style of life.
Project description:In this study, expression analysis using electrochemically synthesized Combimatrix 12K DNA microarrays was validated in G sulfurreducens. Growth under nitrogen fixing conditions and growth in ammonium amended medium, respectively, were the experimental and control conditions. Expression analysis using this platform was also compared to expression analysis on whole cDNA microarrays. Keywords: two-condition comparison
Project description:Nitrogen is major nutrient for plant growth. Two forms for inorganic nitrogen are available for plant, ammonium and nitrate. External status of them affects largely plant growth and production. Generally, root is a sole organ to uptake nitrogen. Hence, identifying regulatory genes depend on nitrogen status in roots is important to improve sustainable production or rice. To isolate the candidate gene, array experiments were performed. Consequently, we isolated genes which showed marked accumulation in deficient and sufficient concentrations of ammonium in roots.
