背景回顾：CRISPR‐Cas is a powerful DNA double‐strand break technology with wide‐ anging applications in plant genome modification. 

受制因素：However, the efficiency of genome editing depends on various factors including plant genetic transformation processes and types of modifications desired.

提出问题：Agrobacterium infection is the preferred method of transformation and delivery of editing components into the plant cell. While this method has been successfully used to generate gene knockouts in multiple crops, precise nucleotide replacement, and especially gene insertion into a pre‐defined genomic location, remain highly challenging. 

主要研究：Here we report an efficient, selectable marker‐free site‐specific gene insertion in maize using Agrobacterium infection. 

结果1：Advancements in maize transformation and new vector design enabled increase of targeted insertion frequencies by two orders of magnitude in comparison to conventional Agrobacterium‐mediated delivery. 

结果2：Importantly, these advancements allowed not only a significant improvement of the frequency, but also of the quality of generated events. 

结论：These results further enable the application of genome editing for trait product development in a wide variety of crop species amenable to Agrobacterium‐mediated transformation.

 摘 要 

CRISPR‐Cas是一个强大的DNA双链切割技术，在植物基因组编辑领域具有十分广泛的应用。但是，基因组编辑的效率依赖于各种因素，包括植物遗传转化过程和所需修饰的类型等。农杆菌侵染是最常用的遗传转化和递送编辑组份进植物细胞的方法。该方法已经成功在多个作物系统中用于产生基因敲除突变体，但是精确的核苷酸替换，尤其是在基因组特定区域插入基因等基因组修饰仍然存在很大的挑战。本文中，作者报道了一个玉米中基于农杆菌侵染开发的有效、无选择标记、并且位点特异性的基因插入方法。与传统的农杆菌介导的遗传递送相比，玉米转化的提升和新载体的设计使得靶向插入频率提高了两个数量级。重要的是，这些提升不仅使插入频率有了显著的提高，而且也提高了生成事件的质量。本文所开发的方法进一步使基因组编辑技术应用于农杆菌介导的多种作物品种的性状产品开发成为可能。