Development of an itraconazole resistance gene as a dominant selectable marker for transformation in Aspergillus oryzae and Aspergillus luchuensis

Biosci Biotechnol Biochem. 2021 Feb 24;85(3):722-727. doi: 10.1093/bbb/zbaa080.


There are only a few combinations of antifungal drugs with known resistance marker genes in the Aspergillus species; therefore, the transformation of their wild-type strains is limited. In this study, to develop the novel dominant selectable marker for itraconazole, a fungal cell membrane synthesis inhibitor, we focused on Aspergillus luchuensis cyp51A (Alcyp51A), which encodes a 14-α-sterol demethylase related to the steroid synthesis pathway. We found that the G52R mutation in AlCyp51A and the replacement of the native promoter with a high-expression promoter contributed to itraconazole resistance in Aspergillus oryzae, designated as itraconazole resistant gene (itrA). The random integration in the A. luchuensis genome of the itrA marker cassette gene also allowed for transformation using itraconazole. Therefore, we succeed in developing a novel itraconazole resistance marker as a dominant selectable marker for transformation in A. oryzae and A. luchuensis.

Keywords: Aspergillus luchuensis; Aspergillus oryzae; cyp51A; itraconazole resistance gene; selectable marker.

MeSH terms

  • Antifungal Agents / pharmacology*
  • Aspergillus / drug effects*
  • Aspergillus / genetics
  • Aspergillus oryzae / drug effects*
  • Aspergillus oryzae / genetics
  • Drug Resistance, Fungal / genetics*
  • Genes, Fungal
  • Genetic Markers*
  • Itraconazole / pharmacology*


  • Antifungal Agents
  • Genetic Markers
  • Itraconazole

Supplementary concepts

  • Aspergillus luchuensis