CRISPR-based editing of the omega- and gamma-gliadin gene clusters reduces wheat immunoreactivity without affecting grain protein quality
Wheat immunotoxicity is associated with abnormal reaction to gluten-derived peptides. Attempts to reduce immunotoxicity using breeding and biotechnology often affect dough quality. Here, the multiplexed CRISPR-Cas9 editing of cultivar Fielder was used to modify gluten-encoding genes, specifically focusing on omega- and gamma-gliadin gene copies, which were identified to be abundant in immunoreactive peptides based on the analysis of wheat genomes assembled using the long-read sequencing technologies. The whole genome sequencing of an edited line showed mutation or deletion of nearly all omega-gliadin and half of the gamma-gliadin gene copies and confirmed the lack of editing in the alpha/beta-gliadin genes. The estimated 75% and 64% reduction in omega- and gamma-gliadin content, respectively, had no negative impact on the end-use quality characteristics of grain protein and dough. A 47-fold immunoreactivity reduction compared to non-edited line was demonstrated using antibodies against immunotoxic peptides. Our results indicate that the targeted CRISPR-based modification of the omega- and gamma-gliadin gene copies determined to be abundant in immunoreactive peptides by analyzing high-quality genome assemblies is an effective mean for reducing immunotoxicity of wheat cultivars while minimizing the impact of editing on protein quality.