Comprehensive analysis of transcription factors involving conidiation in Aspergillus oryzae

Masahiro Ogawa1, Masafumi Tokuoka1, Ken-ichiro Matsushima1, Tadashi Takahashi1, Tomomi Toda2, Masayuki Machida2, Yasuji Koyama1

Author address: 

1Noda Institute for Scientific Research, Noda 399, Noda, Chiba 278-0037, Japan, Japan, 2National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan, Japan


Focused studies of the conidiation control in Aspergilli have been carried out in A. nidulans12288;and A. fumigatus. Understanding of the conidiation control in koji-mold A. oryzae is important to improve productivity in the Japanese fermentation food, such as soy sauce, miso, and sake. However, little is known about the conidiation control in A. oryzae. Recently, it is reported that conidiation control in A. fumigatus is different from that of A. nidulans1). Thus, we are interested in examining whether the regulatory mechanism of conidiation is different among A. oryzae and other Aspergilus species. We constructed a series of A. oryzae mutants in which each ortholog of the A. nidulans conidiation regulators genes (brlA, fluG, flbA, flbB, flbC, flbD, flbE, abaA or wetA) was disrupted. The fluG, brlA, abaA and wetA orthologs disruption mutants of A. oryzae showed the fluffy, bristle, abacus, and wet-white phenotypes, respectively, as has been shown in the corresponding disruption mutants of A. nidulans. Moreover, disruption of the flbA ortholog caused loss of conidiation and reduction of the aerial hyphal extension. The flbB, flbC, flbD, and flbE orthologs disruption mutants of A. oryzae exhibited the delayed conidiation phenotype. These results suggest that upstream regulation mechanism for conidiation in A. oryzae is similar to that in A. nidulans, which is shown to be different from that in A. fumigatus. In contrast, the brlA ortholog disruption mutant showed the identical phenotypes among A. oryzae, A nidulans and A. fumigatus, suggesting that the role of brlA in downstream conidiation regulation is conserved among these species. Additionally, the function of the abaA and wetA are likely conserved in A. oryzae and A. nidulans, given the similarity of mutant phenotypes between the two species. Results of DNA microarray analysis with these disruption mutants were consistent with the above-mentioned findings. Finally, we obtained the novel conidiation mutants from a comprehensive disruption library of the transcription control genes in A. oryzae. We will also report results of analysis with these disruption mutants

abstract No: 


Full conference title: 

    • ECFG 9th (2008)