Transcriptional Analysis of an Ammonium-Excreting Strain of Azotobacter vinelandii Deregulated for Nitrogen Fixation

The transcriptional differences found during stationary-phase ammonium accumulation show a strong contrast between the deregulated (nifL disrupted) and wild-type strain, and to what was reported for the wild-type strain under exponential growth related to key processes involved in driving the process of nitrogen fixation in A. vinelandii. These results further illuminate a number of additional genes associated with siderophore synthesis, molybdate transfer and electron transfer that are likely associated with biological nitrogen fixation. Overall design: Azotobacter vinelandii was grown in standard Burk's media and standard Burk's media containing 20 mM Ammonium sulfate. Azotobacter vinelandii mutant strain deregulated for nitrogen fixation was grown in standard Burk's media. All samples were harvested at various time points, total RNA was extracted and mRNA was enriched. Libraries were constructed, and RNA was sequenced using Illumina paired-end reads.