Targeted Editing of the StPDS Gene using the CRISPR/Cas9 system in Tetraploid Potato
The CRISPR/Cas9 system has been applied in a variety of plants for targeted gene editing due to its accuracy, high efficiency, and low price. It has been reported that the CRISPR/Cas9 system can lead to mutation in potato, however, the mutation patterns and genotypes of CRISPR/Cas9-induced mutants in tetraploid potato plants have not yet been disclosed in detail. In the present study, the Solanum tuberosum phytoene desaturase (StPDS) gene was selected for inducing targeted mutagenesis. The obtained StPDS knockout mutants exhibited a mutation frequency of 46.67% and clear albino phenotypes. All transgenic plants were tested for the hygromycin resistance gene and a high positive transformation frequency (96.77%) was observed in all tested resistant plants. Genotype analysis of the mutants revealed that heterozygotes accounted for 35.51%, chimeras accounted for 64.29%, and no homozygotes and biallelic mutations were detected. The patterns of the detected mutations consisted mainly of 1 to 2-nucleotide insertions and deletions, followed by 2-bp replacements. In short, the results of this study prove that the CRISPR/Cas9 system is an effective approach for cultivated potato gene engineering.