CRISPR Editing Opens Path to Tear-Free Onions

Scientists in Japan have unlocked a way to reduce the tear-inducing compounds in onions using CRISPR-Cas9 genome editing. By targeting and suppressing the lachrymatory factor synthase (LFS) gene, the research team successfully decreased the production of lachrymatory factor, which is the volatile chemical responsible for causing eye irritation when onions are cut. This achievement marks a milestone in onion improvement, as it is the first reported application of genome editing to modify an onion-specific trait.

To edit the target gene, root calluses were transformed using Agrobacterium carrying CRISPR tools and visual markers such as green fluorescent protein (GFP). High-performing callus lines were selected based on high and stable GFP expression. After verifying the successful mutations through molecular screening, the edited lines were regenerated using plant tissue culture. Subsequent testing confirmed that the modified plants had significantly reduced LFS enzyme activity in both their leaves and bulbs.

Although the edited plants showed morphological growth abnormalities and failed to set seed due to prolonged tissue culture, the study provides critical proof of concept for trait modification in onions. By continuing to refine these tissue culture and regeneration pathways, researchers could overcome these developmental hurdles to pave the way for commercially viable, tear-free onions with enhanced health-functional properties.

Read the abstract in Frontiers of Plant Science to learn more.