Non-nodular Endophytic Bacterial Symbiosis and the Nitrogen Fixation of Gluconacetobacter diazotrophicus

There is a need to reduce the negative polluting influence of mineral nitrogen fertilizers and to develop a more sustainable climate smart agriculture capable of meeting our future food security needs. Biological nitrogen fixation can have a role in this if it can be applied to the major food crop plants. Certain strains of the obligate nitrogen-fixing bacterial endophyte Gluconacetobacter diazotrophicus have the necessary attributes for this role. An 'extra-ordinary endophyte' this bacterium is one of relatively few that has mechanisms to cope with high levels of sucrose, an acidic pH, a wide range of oxygen environments, nitrogen fixation, as well as having respiratory chain attributes that make it a possible candidate eukaryote proto-mitochondria. Having a small genome relative to other endophytes, it is typical of facultative intracellular colonizers, with a life cycle that involves horizontal transfer to other high sucrose species via insects and potential vertical transfer through seeds. Every method used for demonstrating nitrogen fixation in rhizobia have been used to demonstrate nitrogen fixation in G. diazotrophicus both in vitro and in planta, and field trials demonstrate yield increases and the potential to reduce nitrogen fertilizer use, meeting both food security and climate smart agriculture needs.