Figure 2.

CRISPR/Cas9‐induced null mutants of BnTT8 in B. napus. (a) The BnTT8 gene model includes seven exons (box) separated by six introns (represented by the solid line). The positions of the N‐terminal MYB interaction region (MIR) domain, the WD/AD domain and the bHLH domain in the C‐terminal region are marked in the model. The vertical line in the gene model indicates the target site, and the arrow indicates the sgRNA direction. The target sequences are shown with the PAM underlined. (b) The CRISPR/Cas9 construct houses the following: a hygromycin resistance cassette consisting of the hygromycin phosphotransferase coding sequence driven by the cauliflower mosaic virus 35S promoter; a Cas9 expression cassette comprising the sequence encoding Cas9 driven by P_35S; and four sgRNAs (S1‐S4) driven by the U3d, U3b, U6‐1 and U6‐29 promoters from Arabidopsis. (c) Sequences at the sgRNA target sites of BnTT8 homozygous mutants in T₂ generation. The protospacer adjacent motif (PAM) is underlined, and nucleotide indels are marked in red, with details labelled at right, ‘a’ and ‘c’ represent the mutated alleles of the target gene on BnA09.TT8 and BnC09.TT8b, respectively. ‘aaCC’, ‘AAcc’ and ‘aacc’ represent homozygous mutations of the target gene in BnA09.TT8, BnC09.TT8b and both copies, respectively.