当前水稻品种的快速升级改良急需精准而高效的育种技术。新型基因组精准编辑工具-引导编辑技术（Prime Editing，PE），能够在不诱导基因组产生DSB及不提供外源DNA修复模板的情况下在靶位点实现所有12种单碱基间的自由转换，多碱基的精准插入或缺失。因此，该技术完美契合了作物精准改良的需求，未来必将成为水稻精准育种的核心技术。然而，根据最近已发表的及我们前期未发表的工作表明PE技术在水稻中编辑效率很低。本项目针对PE技术效率低下的突出问题，在前期研究的基础上，通过深入剖析水稻引导编辑器各元件如何影响编辑效率，进而筛选出有利于提高水稻引导编辑效率的元件。在此基础上，通过综合叠加、组合各种有利元件，构建适合于水稻的高效率引导编辑器，并尝试将其应用于水稻主栽品种农艺性状的精准定向改良。本项目的研究将为水稻甚至其它主要农作物的精准定向改良提供强有力的技术支撑，具有广阔的应用前景。

The precise and efficient breeding technologies are urgently needed for the rapid improvement of rice elite varieties. Prime editing (PE), a novel precise genome engineering tool, was recently developed that can introduce all 12 base-to-base conversions, precise small indels and their combinations into target site without requiring DNA double-strand break formation and homology-directed repair. Therefore, it holds great promise for precision breeding of crops. However, our unpublished work and other’s recent work indicate that prime editors have relatively low efficiencies in rice. In this project, we will use a reporter system that was established in our previous study to conduct step-by-step optimization of the structure of prime editors to improve their efficiencies in rice. We will systematically probe the relationship between pegRNA structure and prime editing efficiency and also test the effect of different Cas9 proteins (or variants) and reverse transcriptase on editing frequency. Then, we will combine the beneficial components to construct the highly efficient prime editors and use them for trait improvement in elite rice varieties. The findings from this project will be very important for advancing precision breeding in rice and other crops.