木薯褐色条斑病毒（CBSV）和非洲木薯花叶病毒（ACMV）对作为全球第六大粮食作物的木薯生产造成严重危害，目前尚无有效防治方法，特别是缺乏CBSV抗性育种材料。由于Potyviruses的复制依赖于病毒基因组连接蛋白（VPg）与寄主eIF4E类因子的相互作用，本研究通过 Y2H、BiFC、丙氨酸扫描突变等手段确定与CBSV-VPg相互作用的木薯eIF4E 类寄主因子及与CBSV-VPg互作的关键位点，利用TALENs 和CRISPR-Cas9实现对该因子关键互作位点的定点编辑，阻断与CBSV-VPg相互作用而使CBSV不能复制，探索通过编辑寄主因子进行木薯抗CBSV分子育种新途径。再结合分子和传统育种设计，培育针对不同地区需求的广谱、安全、同时抗CBSV和ACMV可遗传的木薯新种质。本研究不仅为我国木薯抗病育种提供全新的理论和技术方法，也将为探索其它重要农作物更有效的病毒病防治新策略。

Cassava (Manihot esculenta Grantz) is an important crop that is extensively used as a source of food, and is a potential source of bio-fuel. Cassava production is severely affected by two major diseases, Cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) which are caused by African cassava mosaic virus (ACMV) and Cassava brown steak virus (CBSV), respectively. As no chemical controls are available for viral diseases, genetic resistance obtained through either traditional breeding or transgenic means are the primary approaches to protect crops from viral diseases. These approaches are often challenged by rapid overcoming of the resistant varieties soon after their release. Resistance generated via transgenic approaches, including RNAi-mediated resistance, requires the transfer of foreign genes into crops, which raises some regulatory concerns and dampens the acceptance of the resistant crops by consumers and farmers alike. In this project, we propose to modify existing host genes by editing a few critical amino acids to create incompatibility between viral proteins and host proteins, generating CBSV resistant cassava by using the newly developed TALENs (Transcription activator-like effector nucleases) and CRISPR-Cas9 (Clustered regularly interspaced short palindromic repeats). It also aims to block viral replication at the onset of infection, mitigating the risk of resistance breaking. To obtain the goal we design the the following experiments: 1) Screening cassava target gene for editing against CBSV through Y2H; 2) Mapping target interaction sites on the eIF4E or other target gene by alanine scanning mutagenesis; 3) Edit the host gene with TALENs which will be introduced into host plant either by virus vector, or bombardment. Base on the approach developed, we will try to exploit the combination of natural and gene editing resistance to ACMV and CBSV to generate safe non-transgenic Cassava with CBSV and ACMV resistant simultaneously through combining with molecular design and traditional breeding. Completion of this project will not only generate novel cassava immunity against cassava viral diseases, but also contribute to molecular immunity breeding in other important crops such as maize, wheat and rice against viral infections.