Analysis of differential gene expression across regions of the Aspergillus oryzae mycelium.

Kumiko Masai1, Jun-ichi Maruyama1, Harushi Nakajima2, Kazutoshi Sakamoto3, Osamu Akita3, Katsuhiko Kitamoto1.

Author address: 

1Department of Biotechnology, University of Tokyo, Tokyo, Japan. 2Department of Agricultural Chemistry, Meiji University, Kawasaki, Japan. 3National Research Institute of Brewing, Higashi-Hiroshima, Japan.


Regions of differentiation in filamentous fungi mycelia can be observed during growth on solid substrates. This suggests that each of these regions may have different functions during the life cycle of the fungus and accordingly, their characteristics being controlled by gene(s) specifically expressed in each region. Here, we propose a mycelial-scale gene expression analysis approach to determine the gene(s) responsible for this phenomenon in the industrially important filamentous fungus Aspergillus oryzae. Upon observation of a mycelium of A. oryzae, three distinct regions were detected. They were designated as tip, white and basal, based on their visual characteristics. Tip cells growing at the edge of the colony comprised the tip region, whereas aerial hyphae and developed conidiophores were observed in the white and basal regions, respectively. Differential expression of genes in the three regions was detected by RT-PCR in the preliminary analysis. Microarray analysis using the A. oryzae cDNA chip was performed to identify the genes that are specifically expressed in each region. Genes involved in the translation process were abundant in the tip region, whereas, genes encoding transporters were expressed at high levels in the basal region. This result supports the assumption that the genes expressed in each region reflect the characteristics observed in each region. Thus, this study has laid the basic foundation in the investigation of what makes each region unique. Further characterization of each region and functional analysis of selected genes will be presented.

abstract No: 


Full conference title: 

23rd Fungal Genetics Conference
    • Fungal Genetics Conference 23rd (2002)