Fig. 8: Efficient engineering of plant architecture through HDR.

a Schematic of the desired mutations in the wild-type OsCCD7 allele. Modifications of nucleotides added into the repair templates at the sgRNA binding and PAM sequences to avoid retargeting of the repaired sequence by VirD2-Cas9 are shown. The sgRNA binding sequence is indicated by an arrow and removal of the PAM and insertion of the EcoRI recognition sequence (underlined) is indicated by a line. Nucleotide modifications along with the corresponding amino acids are represented by capital, colored, and bold letters. The respective wild-type amino acids (capital and bold) are also shown. b Representative gels of EcoRI digestion for HDR confirmation. Target (CCD7) flanking 445 bp PCR amplified fragments were subjected to EcoRI digestion. EcoRI digestion confirmed the proper digestion to produce 270 + 175 bp fragments (indicated by arrowheads) and repair in the plants regenerated from calli bombarded with repair templates with mT-RB and Cas9-VirD2 or VirD2-Cas9. Repair templates without mT-NRB with VirD2-Cas9 and Cas9 with mT-RB repair templates were used as control. Lines confirmed with EcoRI digestion are indicated with asterisks. c Photos of plants with engineered modifications. Seed of the progeny plants were grown on soil in the greenhouse and pictures were taken 40 days after germination. d Heritability of the repaired modifications. The target (CCD7) flanking PCR amplified 445-bp fragments from the progeny plants of the selected lines were subjected to EcoRI digestion. EcoRI digestion produced 270 + 170 bp fragments in lines that had inherited the modification. Four out seventeen plants are homozygous for the EcoRI site. e Alignment of the Sanger sequencing reads and representative chromatograms of the EcoRI digestion of confirmed homozygous plants. The repair-specific nucleotide modifications are shown in blue and their exact locations are indicated by arrowheads (red). The representative chromatograms show the exact repair at the targeted locus.