利用高通量碱基编辑技术创制抗除草剂水稻新种质

Rice is the stable food for most people in China and also one of the basic cereal crops in the world. Weed control is one of the major problems in rice production, and it is also a technical problem in direct seeding rice and upland rice production. Develop herbicide-resistant rice varieties is the most effective way to control weeds in the field. For a long time, herbicide-resistant germplasm were developed mainly by chemical and physical mutagenic breeding or introducing resistance genes from microorganisms. Base editors enable precise base alterations in the target gene without inducing DNA double-stranded breaks, and thus are important tools for overcoming the disadvantages of traditional mutagenic breeding and avoiding the GMO regulation. In order to exploit potential unknown herbicide-resistant mutations in rice, we plan to introduce saturation mutations in three herbicide target enzymes, ALS, EPSPS and HPPD, via high-throughput base editing technology. We will further introduce different elite herbicide-resistant mutations into rice cultivars in future, to deal with the growing problems of weed resistance.

水稻是世界上最重要的粮食作物之一，也是多数中国人的主粮。防治杂草是水稻生产的主要问题之一，也是困扰直播稻和旱稻生产的技术难题。培育具有除草剂抗性的水稻品种是防治田间杂草危害最经济、有效的途径。一直以来，培育抗除草剂种质资源主要通过在微生物中挖掘抗性基因或利用化学和物理诱变的方法筛选抗性突变体。碱基编辑技术能够在不引入DNA双链断裂也不需要修复模板的情况下实现安全、高效、精准的碱基替换，借助该技术一方面能够规避转基因风险，另一方面能够极大的克服传统诱变育种的弊端，定向高效地创制系列点突变。本项目拟以水稻为材料，选择三个在生产上具有巨大应用潜力的除草剂靶标酶：ALS，EPSPS和HPPD，利用高通量碱基编辑技术对其关键功能域进行饱和突变，充分挖掘潜在的未知抗性突变并且对所获得的突变体进行除草剂抗性及农艺性状评价，为今后利用不同抗性突变进行聚合育种，创制抗多种除草剂的非转基因水稻新种质打下基础。

防治杂草是水稻生产的主要问题之一，培育具有除草剂抗性的水稻品种是防治田间杂草危害最经济、有效的途径。本项目以水稻为材料，选择多个在生产上具有重要应用潜力的除草剂靶标酶：ALS、EPSPS、HPPD和ACCase，利用高通量碱基编辑技术对其关键功能域进行饱和突变，充分挖掘潜在的抗性突变并且对所获得的突变体进行除草剂抗性及农艺性状评价。我们在以上四个靶标酶上均筛选出具有抗性效果的点突变，其中在ACCase上筛选出二十多个抗性突变。同时我们也发现大多数具有抗性的点突变存在抗性不强，或者影响水稻的农艺性状等问题，因此在田间生产中应用需要综合其它技术手段。总体上，本项目创制了一批具有除草剂抗性效果的非转基因水稻新种质，为今后在水稻里聚合多种优良抗性以应对越来越严重的杂草抗性问题作充分的准备。