Genome Editing - a precise and fast new breeding method

CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats/Cas protein) is based on the natural immune system of bacteria. As defence against viruses, certain bacteria are able to capture DNA from viruses and use it to create DNA segments – allowing them to directly target similar viruses in consequent attacks, cutting their DNA apart.

Researchers can use the same principle in genome editing. First step is the identification of target genes, i.e., target DNA sequence in the plant – for example, those genes that determine the plant’s susceptibility to pathogens. Guide RNA is built according to the targeted DNA sequence. Within the nucleus of the plant cell, it finds the correct location and carries Cas, the cutting enzyme, with it. The Cas cuts the targeted DNA strand, creating a double-strand break. The Cas protein can be used in combination with the cell’s natural DNA repair processes to activate or repress genes or enable specific nucleotides to be changed into different nucleotides.

There are different forms of applications of genome editing. The three types of Site-Directed Nucleases can be induced with CRISPR/Cas: SDN-1 (deletions or point mutations), SDN-2 (targeted changes of a few nucleotides) or SDN-3 (targeted insertion of genes or gene sequences, including transgenic insertions).