Reconstruction and validation of genome-scale metabolicmodel for Gluconacetobacter diazotrophicus; a plant growthpromoting bacterium

Gluconacetobacter diazotrophicus is an acid tolerant, gram negative and obligate aerobe bacterium whose genome is fully sequenced. It has important agricultural value such as nitrogen fixation, producing plant promoting enhancers, increasing solubility of zinc and phosphorus and increasing plant's resistance against certain bacteria or fungi. It also produces industrially and pharmaceutically valuable carboxyl acid gluconic acid which is used as antiseptic and chelating agents. Unlike other diazotrophs, G. diazotrophicus is an endophyte bacterium living within the plant without causing any harm. Its natural host is sugarcane: a monocot plant with high sugar content. There are studies about plant growth promoting and nitrogen fixation characteristics but the underlying metabolic pathways are not fully understood. Adopting a system biology approach; reconstructing the genome-scale metabolic model (GSMM) for the Gluconacetobacter diazotrophicus and applying Flux Balance Analysis (FBA), can not only help us to find the carbon flux of its metabolism but also to elucidate how it works and responds to the environmental factors. Consequently, the analysis of the GSMM can be also used for determining the target pathways for metabolic engineering considering utilitarian exploitation of the organism. In the light of the above, a genome-scale metabolic model for G. diazotrophicus consisting of 1754 reactions, 1629 metabolites and 848 genes was constructed.