Up to now, most of published CRISPR/Cas applications in plants (>97%) use an SDN-1 approach, where the traits arise from knocking-out or silencing target genes. However, there is a significant potential in gene editing approaches (SDN-2) where small, targeted modifications using homology-directed repair (HDR) can confer new characteristics to key genes.
In a recent publication, a pioneering research group from the Henan Agricultural University identified a single-nucleotide polymorphism (SNP) in the ethylene receptor gene SlEIN4 in tomato, associated with fruit firmness within a GWAS study with 266 tomato accessions. By SDN-2 targeted gene editing on SlEIN4, scientists achieved significant improvements in fruit ripening and firmness.
The specific modification of the SlEIN4 gene affects the expression of enzymes involved in cell wall breakdown, producing a more robust microstructure of the fruit pericarp (the outer layer of the fruit), and ultimately an increased resistance to physical stress, improved resistance to damage during storage and transportation, extending shelf-life and reducing waste.
These results show the potential of using SDN-2 CRISPR for precise enhancement of tomato traits beyond simple gene knock-out or silencing. At HRB, we’re proud to announce that we are already offering SDN-2 commercially in tomatoes, bringing potential specific edits like the one described above to market for better crop management and sustainability.
