Aspergillus oryzae has been widely used in Japanese fermentation industries, Japanese alcohol beverage, soy bean paste, soy sauce and rice vinegar for longer than a thousand of years. High potential of secretory production of proteins has led A. oryzae to extensive use in modern biotechnology. The A. oryzae genome size is very close to those of A. flavus and A. niger, and 20-30% bigger than those of A. nidulans and A. fumigatus. Comparison of A. oryzae genome with those of the two species of smaller genome size revealed existence of non-syntenic blocks (NSBs) specific to the A. oryzae genome distributed in a mosaic manner throughout its genome. The NSBs are highly enriched with the genes concerning secondary metabolism and the A. oryzae-specific genes including those expanded in the A. oryzae genome. The transcriptional expression levels of the genes on NSBs were significantly lower than those on syntenic blocks (SBs) by the DNA microarray analysis. The genes on NSBs and SBs were globally down- and up-regulated, respectively, at heat shock. In contrast, the genes on NSBs appeared globally up-regulated in solid-state cultivation (SSC), which is widely used in the Japanese fermentation industries. There are several factors known to affect expression of CCS-specific genes including low water activity and physical barrier. Considering that most of the extra homologs are involved in metabolism, the enzymes encoded on the NSB-genes might enhance the potential of degrading raw materials. Interestingly, most of the extra homologs repressed at heat-shock in submerged culture were not repressed in membrane cultivation condition, which was a mimic of SSC. These results suggest that SSC is an ideal culture condition to take advantage of utilizing the genes uniquely existing in the A. oryzae genome.
Full conference title:
9th EUROPEAN CONFERENCE ON FUNGAL GENETICS
- ECFG 9th (2008)