Bilichak Andriy, Gaudet Daniel, Laurie John
Morden Research and Development Center, Agriculture and Agri-Food Canada, Morden, MB, Canada.
The University of Lethbridge, Lethbridge, AB, Canada.
Methods Mol Biol. 2020;2072:165-181. doi: 10.1007/978-1-4939-9865-4_14.
Recent advances in genome engineering are revolutionizing crop research and plant breeding. The ability to make specific modifications to a plant's genetic material creates opportunities for rapid development of elite cultivars with desired traits. The plant genome can be altered in several ways, including targeted introduction of nucleotide changes, deleting DNA segments, introducing exogenous DNA fragments and epigenetic modifications. Targeted changes are mediated by sequence specific nucleases (SSNs), such as zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and CRISPR (clustered regularly interspersed short palindromic repeats)-Cas (CRISPR associated protein) systems. Recent advances in engineering chimeric Cas nucleases fused to base editing enzymes permit for even greater precision in base editing and control over gene expression. In addition to gene editing technologies, improvement in delivery systems of exogenous DNA into plant cells have increased the rate of successful gene editing events. Regeneration of fertile plants containing the desired edits remains challenging; however, manipulation of embryogenesis-related genes such as BABY BOOM (BBM) has been shown to facilitate regeneration through tissue culture, often a major hurdle in recalcitrant cultivars. Epigenome reprogramming for improved crop performance is another possibility for future breeders, with recent studies on MutS HOMOLOG 1 (MSH1) demonstrating epigenetic-dependent hybrid vigor in several crops. While these technologies offer plant breeders new tools in creating high yielding, better adapted crop varieties, constantly evolving government policy regarding the cultivation of plants containing transgenes may impede the widespread adoption of some of these techniques. This chapter summarizes advances in genome editing tools and discusses the future of these techniques for crop improvement.
基因组工程的最新进展正在彻底改变作物研究和植物育种。对植物遗传物质进行特定修饰的能力为快速培育具有所需性状的优良品种创造了机会。植物基因组可以通过多种方式改变，包括靶向引入核苷酸变化、删除DNA片段、引入外源DNA片段和表观遗传修饰。靶向变化由序列特异性核酸酶（SSN）介导，如锌指核酸酶（ZFN）、转录激活样效应物核酸酶（TALEN）和CRISPR（成簇规律间隔短回文重复序列）-Cas（CRISPR相关蛋白）系统。工程化与碱基编辑酶融合的嵌合Cas核酸酶的最新进展使得碱基编辑更加精确，并能更好地控制基因表达。除了基因编辑技术外，将外源DNA导入植物细胞的递送系统的改进提高了成功的基因编辑事件的发生率。培育含有所需编辑的可育植物仍然具有挑战性；然而，对胚胎发生相关基因如BABY BOOM（BBM）的操纵已被证明有助于通过组织培养实现再生，而组织培养往往是顽固品种的主要障碍。对表观基因组进行重编程以提高作物性能是未来育种者的另一种可能性，最近对MutS同源物1（MSH1）的研究表明，表观遗传依赖的杂种优势存在于几种作物中。虽然这些技术为植物育种者提供了创造高产、适应性更强的作物品种的新工具，但政府关于转基因植物种植的政策不断变化，可能会阻碍其中一些技术的广泛应用。本章总结了基因组编辑工具的进展，并讨论了这些技术在作物改良方面的未来。
