Simultaneous modification of three homoeologs ofTaEDR1by genome editing enhances powdery mildew resistance in wheat

Summary Wheat ( Triticum aestivum L.) incurs significant yield losses from powdery mildew, a major fungal disease caused by Blumeria graminis f. sp. tritici ( Bgt ). enhanced disease resistance1 ( EDR 1) plays a negative role in the defense response against powdery mildew in Arabidopsis thaliana ; however, the edr1 mutant does not show constitutively activated defense responses. This makes EDR 1 an ideal target for approaches using new genome‐editing tools to improve resistance to powdery mildew. We cloned Ta EDR 1 from hexaploid wheat and found high similarity among the three homoeologs of EDR 1 . Knock‐down of Ta EDR 1 by virus‐induced gene silencing or RNA interference enhanced resistance to powdery mildew, indicating that Ta EDR 1 negatively regulates powdery mildew resistance in wheat. We used CRISPR /Cas9 technology to generate Taedr1 wheat plants by simultaneous modification of the three homoeologs of wheat EDR 1 . No off‐target mutations were detected in the Taedr1 mutant plants. The Taedr1 plants were resistant to powdery mildew and did not show mildew‐induced cell death. Our study represents the successful generation of a potentially valuable trait using genome‐editing technology in wheat and provides germplasm for disease resistance breeding.