Analysis of nif and regulatory genes in Acetobacter diazotrophicus

The focus of our collaborative research program is the identification and characterization of nif and related regulatory genes of Acetobacter diazotrophicus in order to understand what factors influence nitrogen fixation in this unique diazotroph. To date, the following genes have been isolated from genomic libraries and are being analyzed: nifHDK, nifA, nifB, nifV, nifE and ntrBC. In addition, Nif− mutants have been constructed by insertional mutagenesis. These mutants are currently being used in inoculation experiments of sterile sugarcane plants to determine whether nitrogen fixed by A. diazotrophicus is significant for plant nutrition.