Agronomy Department, University of Florida Institute of Food and Agricultural Sciences, Gainesville, FL, USA.
DOE Center for Advanced Bioenergy and Bioproducts Innovation, Gainesville, FL, USA.
Plant Genome. 2023 Jun;16(2):e20298. doi: 10.1002/tpg2.20298. Epub 2023 Jan 24.
Many of the world's most important crops are polyploid. The presence of more than two sets of chromosomes within their nuclei and frequently aberrant reproductive biology in polyploids present obstacles to conventional breeding. The presence of a larger number of homoeologous copies of each gene makes random mutation breeding a daunting task for polyploids. Genome editing has revolutionized improvement of polyploid crops as multiple gene copies and/or alleles can be edited simultaneously while preserving the key attributes of elite cultivars. Most genome-editing platforms employ sequence-specific nucleases (SSNs) to generate DNA double-stranded breaks at their target gene. Such DNA breaks are typically repaired via the error-prone nonhomologous end-joining process, which often leads to frame shift mutations, causing loss of gene function. Genome editing has enhanced the disease resistance, yield components, and end-use quality of polyploid crops. However, identification of candidate targets, genotyping, and requirement of high mutagenesis efficiency remain bottlenecks for targeted mutagenesis in polyploids. In this review, we will survey the tremendous progress of SSN-mediated targeted mutagenesis in polyploid crop improvement, discuss its challenges, and identify optimizations needed to sustain further progress.
许多世界上最重要的作物都是多倍体。它们的细胞核中存在两套以上的染色体，并且多倍体的生殖生物学通常异常，这给常规的育种带来了障碍。每个基因的同源拷贝数量更多，使得随机突变育种成为多倍体的一项艰巨任务。基因组编辑技术的出现彻底改变了多倍体作物的改良，因为可以同时编辑多个基因拷贝和/或等位基因，同时保留优良品种的关键特性。大多数基因组编辑平台都采用序列特异性核酸酶（SSN）在目标基因处产生 DNA 双链断裂。这种 DNA 断裂通常通过易错的非同源末端连接过程进行修复，这常常导致移码突变，导致基因功能丧失。基因组编辑增强了多倍体作物的抗病性、产量构成和终用途品质。然而，候选靶标的鉴定、基因型分析和高诱变效率的要求仍然是多倍体中靶向诱变的瓶颈。在这篇综述中，我们将调查 SSN 介导的靶向突变在多倍体作物改良方面的巨大进展，讨论其面临的挑战，并确定需要进行哪些优化以维持进一步的进展。
