Abstract：Azospirillum brasilense is a nitrogen fixing, plant growth promoting rhizobacterium, and it can interact with roots of several economically important cereals, such as maize, wheat, rice. NifA is a common transcriptional activator for all nitrogen fixation gene. In some diazotrophs, NifL controls negatively NifA activity. But there are not been found factors interaction with NifA in A. brasilense. The hybrid two component system protein Org35 was obtained by means of the yeast two-hybrid system with NifA as bait in our previous research. In this study, the interaction between Org35 and NifA was discussed. The results indicated the PAS domain was mediated in the interaction between Org35 and NifA.
