Characterization of Genes Involved in Regulation of Nitrogen Fixation and Ammonium Sensing in Acetobacter diazotrophicus, an Endophyte of Sugarcane

Abstract

A. diazotrophicus is the major nitrogen fixing bacterium isolated from the leaves, stems and roots of sugarcane collected in various sites of Brazil, Australia, Mexico and Cuba and is considered to be a true endophyte based on its initial isolation from surface sterilized tissues and more recently on ultra-microscopic examinations of infected tissues. Other unique characteristics of this alpha-group proteobacteria diazotroph include the ability to grow and fix nitrogen at low pH, production of acetic acid from sucrose or glucose, and growth at high sucrose concentrations. Our objective was to isolate regulatory and ammonium assimilatory genes in order to understand what factors influence nitrogen fixation in this unique habitat.