Erwinia amylovora, the bacterium that causes the fire blight disease in apple, triggers its infection through the DspA/E effector which interacts with the apple susceptibility protein MdDIPM4. Researchers used the CRISPR-Cas9 system to produce defective MdDIPM4 which were delivered to susceptible apples (cultivars, ‘Gala’ and ‘Golden Delicious’) using Agrobacterium tumefaciens. The results are published in the Plant Biotechnology Journal.
A total of 57 transgenic lines were generated with an editing efficiency of 75%. Out of the 57, 7 lines exhibited successful mutation leading to loss of function of MdDIPM4. These lines were exposed to fire blight and results showed a highly significant reduction of susceptibility when compared to the control. A strategy based on the heat-shock inducible FLP/FRT recombination system was applied to remove the T-DNA region containing expression cassettes of the editing machinery and selectable marker in those edited lines with reduced susceptibility to the disease.
The results provide information on the development and application of CRISPR-Cas9 for the production of edited apples with a minimal trace of exogenous DNA.
Pompili et al. 2019 Reduced fire blight susceptibility in apple cultivars using a high‐efficiency CRISPR/Cas9‐FLP/FRT‐based gene editing system. Plant Biotechnology Journal. https://doi.org/10.1111/pbi.13253
Source: Crop Biotech Update