Fig. 3

Donor DNA with 40-bp short homologous arms mediated albA gene insertion by the novel CRISPR/Cas9 system in A. niger. a Schematic diagram of albA gene insertion mediated by integrating the donor DNA with 40-bp micro-homologous arms. The donor DNA MHi-albA-hph was co-transformed with linear sgRNA constructs and the Cas9-expressing plasmid pCas9 into wild-type A. niger G1. DSBs were generated by Cas9 under the guide of the sgRNA and were then repaired by HR with the integration of MHi-albA-hph. b Diagnostic PCR analysis of the genetic context of DSBs in albino colonies. Correct integration of the hph marker at the albA locus: 1697 bp (albA-g-F/hph-R) and 1934 bp (hph-F/albA-g-R). M, DNA ladder; 1-11, 11 albino colonies XM6.1-6.11; 12, one black colony XM6.12 without albA insertion