Prime editing efficiently generates W542L and S621I double mutations in two ALS genes of maize

A novel and universal CRISPR/Cas-derived precision genome editing technology named prime editing was developed. However, low prime editing efficiency was shown in transgenic rice lines. We reasoned that enhancing pegRNA expression would be able to improve prime editing efficiency. In this report, we used two strategies to enhance pegRNA expression and constructed a prime editing vector harboring two pegRNA variants for W542L and S621I double mutations in ZmALS1 and ZmALS2. As compared with previous reports in rice, we achieved much higher prime editing efficiency in maize. Our results are inspiring and provide a direction for optimization of plant prime editors.