A Novel Site-Specific Integration System for Genetic Modification of Aspergillus flavus

G3 (Bethesda). 2020 Feb 6;10(2):605-611. doi: 10.1534/g3.119.400699.


Aspergillus flavus is a fungus that produces aflatoxin B1, one of the most carcinogenic secondary metabolites. Understanding the regulation mechanism of aflatoxin biosynthesis in this fungus requires precise methods for genomic integration of mutant alleles. To avoid the disadvantage of DNA integration into the genome by non-homologous or ectopic recombination, we developed a novel strategy for site-specific integration of foreign DNA by using a carboxin-resistant sdh2R allele (His 249 Leu). Our results demonstrated that the transformants were generated with a high efficiency (>96%) of correct integration into the sdh2-lcus of the genome of A. flavus NRRL 3357. The advantage of this method is that introduction of the eGFP expression cassette into the sdh2-locus had little effect on fungal growth and virulence while also being rapid and efficient. This system will be a valuable tool for genetic manipulation in A. flavus To the best of our knowledge, this is the first report on the efficient site-specific integration at the sdh2-locus in the genome of Aspergillus.

Keywords: Aspergillus flavus; sdh2-locus; site-specific integration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aflatoxin B1 / analysis
  • Aflatoxin B1 / biosynthesis
  • Aflatoxin B1 / chemistry
  • Amino Acid Sequence
  • Aspergillus flavus / genetics*
  • Chromatography, High Pressure Liquid
  • Ectopic Gene Expression
  • Genes, Fungal*
  • Genetic Vectors / genetics
  • Iron-Sulfur Proteins / chemistry
  • Iron-Sulfur Proteins / genetics
  • Mutagenesis, Insertional*
  • Phenotype
  • Transformation, Genetic


  • Iron-Sulfur Proteins
  • Aflatoxin B1