An important filamentous fungus Aspergillus oryzae has been used in the fermentation industry for hundreds of years to produce a large number of industrial enzymes and fermented sauces. However, the cellular mechanisms governing these processes are poorly established and understood. We are combining an improved genome annotation through building stoichiometric metabolic model and transcriptomics level to reveal these mechanisms. Using a large set of assembled Expressed Sequence Tag (EST) data and different advanced bioinformatics tools for improved annotation we identified 1,046 newly predicted genes in the genome. Furthermore, it was possible to assign putative protein functions to 398 of the newly predicted genes. Moreover, our annotation strategy resulted in assignment of new putative functions to 1,469 hypothetical proteins already present in the A. oryzae genome database. Using the improved annotated genome with available biochemical pathway databases and literature, we reconstructed the metabolic network of A. oryzae. This network contains 729 enzymes, 1,314 enzyme-encoding genes (10% of the 13,120 total predicted genes), 1,073 metabolites and 1,846 (1,053 unique) biochemical reactions. The metabolic reactions are compartmentalized into the cytosol, the mitochondria, the peroxisome and the extracellular space. Transport steps between the compartments and the extracellular space represent 281 reactions, of which 161 are unique. The metabolic model was validated and shown to correctly describe the phenotypic behavior of A. oryzae grown on different carbon sources. In addition, the model was integrated with transcriptomics data to elucidate overall metabolic response of A. oryzae to alteration of carbon sources. The model serves as an important resource for gaining further insight into our understanding of cell factory A. oryzae.
Full conference title:
9th EUROPEAN CONFERENCE ON FUNGAL GENETICS
- ECFG 9th (2008)