Transposon mutagenesis using a resident DNA transposon Crawler in Aspergillus oryzae industrial strains

Hironobu Ogasawara[1] Tsutomu Satoh[1] Hiroshi Konno[1] Yoji Hata[2] Saori Takahashi[3] Katsuya Gomi[

Author address: 

1Akita Konno Co. Ltd., Akita, Japan, 2Research Institute, Gekkeikan Sake Co. Ltd., Kyoto, Japan, 3Akita Res. Inst. Food and Brewing, Akita, Japan, 4Graduate School of Agricultural Science, Tohoku University, Sendai, Japan


An active DNA transposon Crawler isolated from the genome of industrially important fungus Aspergillus oryzae transposes under extreme stress conditions. The DNA sequencing surveys revealed that the Crawler element is widely distributed among A. oryzae and A. sojae strains, which are commonly used in Japanese traditional fermentation manufacturing. In the present study, we analyzed the relationship between various stress stimuli and inhibition of cryptic splicing of the Crawler mRNA by qRT-PCR to enhance the frequency of Crawler-mediated mutagenesis in an A. oryzae industrial strain, AOK139. Under the optimized stress conditions, in which conidiospores were treated for 6 hr in 20 mM CuSO4 or at 528451;, various phenotypic mutants different from the parent strain were isolated. These mutants exhibited white color in conidiospores, less number of spores formed, shortened aerial hyphae, thin colony mat and so on. DNA sequencing analysis of a white conidia mutant revealed that Crawler was newly inserted within a coding region of wA gene encoding polyketide synthase, which resulted in wA deficiency. The insertion occurred also at a TA site with duplication according to the manner of Crawler transposition. These results suggested that transposon mutagenesis using active Crawler is potentially valuable to improve characteristics of A. oryzae industrial strains.

abstract No: 


Full conference title: 

    • ECFG 10th (2010)