Azotobacter vinelandii is an important model organism for the study of nitrogen fixation, iron-sulfur clusters, alginate biosynthesis, and cyst formation. The complete genome of A. vinelandii DJ was published in 2009. In this chapter we present updated and expanded information for this genome. We present a new phylogeny of pseudomonadaceae that takes into account fully sequenced genomes that have been published since 2009. This phylogeny is in agreement with a previously published phylogeny but is more detailed. We investigate the origin of nitrogen fixation-related genes in A. vinelandii DJ, concluding that they were most likely inherited from an ancestor shared with Pseudomonas stutzeri andTeredinibacter turnerae. We hypothesize that a horizontal gene transfer event including nitrogen fixation genes may have happened between a Gammaproteobacterium ancestor and a Betaproteobacterium ancestor. We conclude by providing information on the presence of group II introns and CRISPR genes in the A. vinelandii DJ genome.
