中文摘要：

CRISPR (定期聚类短 palindromic 重复的 interspaced )/Cas9 系统，是为指向的染色体修正的一种最新发达的技术，成功地在很多种被使用了。在这研究，我们使用了这种技术在玉米执行指向的染色体修正。标记基因 Zmzb7 为指向被选择。sgRNA-Cas9 构造被转变成玉米原物，和 indel (插入和删除) 变化能被检测。有期望的白化体显型的一棵变异的幼苗从屏蔽从 10 个胼胝事件产生的 120 棵幼苗被获得。在玉米的变化效率包含不同颜色的区域也被调查。有在玉米着丝点或 pericentromere 区域的不同表示层次的 12 个地点被选择。sgRNA-Cas9 构造被转变成定序转变原物 genomic DNA 跟随的原物。结果证明在包含不同颜色的区域的基因能被 CRISPR/Cas9 系统高效地指向，不管他们是否被表示。同时，离开目标变化没在没有 PAM 的类似的地点被发现(protospacer 邻近的主题) 或有超过二失配。一起，我们的结果证明 CRISPR/Cas9 系统在玉米是为在 euchromatic 和包含不同颜色的区域的染色体修正的一个柔韧、有效的工具。

英文摘要：

CRISPR （clustered regularly interspaced short palindromic repeats）/Cas9 system, which is a newly developed technology for targeted genome modification, has been successfully used in a number of species. In this study, we applied this technology to carry out targeted genome modification in maize. A marker gene Zmzb7 was chosen for targeting. The sgRNA-Cas9 construct was transformed into maize protoplasts, and indel （insertion and deletion） mutations could be detected. A mutant seedling with an expected albino phenotype was obtained from screening 120 seedlings generated from 10 callus events. Mutation efficiency in maize heterochromatic regions was also investigated. Twelve sites with different expression levels in maize centromeres or pericentromere regions were selected. The sgRNA- Cas9 constructs were transformed into protoplasts followed by sequencmg the transformed protoplast genomic DNA. The results show that the genes in heterochromatic regions could be targeted by the CRISPR/Cas9 system efficiently, no matter whether they are expressed or not. Meanwhile, off-target mutations were not found in the similar sites having no PAM （protospacer adjacent motif） or having more than two mismatches. Together. our results show that the CRISPR/Cas9 system is a robust and efficient tool for genome modification in both euchromatic and heterochromatic regions in maize.