Cell利用基因组编辑技术改良作物数量性状

丰富的遗传变异和高效的筛选体系是限制作物育种的主要因素。基因组编辑技术开创了作物遗传改良的新途径。得益于功能基因组学的研究成果,基因组编辑技术已在控制作物质量性状的功能基因改良中得到应用。与功能基因丰富的遗传变异不同,调控功能基因表达模式的顺式调控序列的自然变异有限。挖掘和创制顺式调控序列的遗传变异,不仅有助于阐明数量性状的调控模式,而且对于作物遗传改良意义重大。最近,冷泉港实验室的番茄育种家Lippman在《Cell》杂志上详细描述了该团队利用CRISPR/Cas9体系改良番茄数量性状的实践。

文章通过系统的试验证实:(1)通过CRISPR/Cas9靶向顺式调控基序能够重建人工驯化的数量性状位点;(2)多重gRNA介导的CRISPR/Cas9对启动子区域进行编辑能够创制出新的、连续的性状变异;(3)跨代CRISPR/Cas9驱动的遗传编辑体系能够高效地筛选和评价数量性状变异;(4)新创制的顺式调控序列等位变异能够在非转基因后代中得到固定;(5)顺式调控序列保守区的变异及其对转录的影响不可以通过表型差异来预测。

可以预见,基于作物数量遗传学和全基因组关联分析的研究成果以及作物基因组编辑技术的突破和改进,通过定点修饰顺式调控序列实现对数量性状的精准操控,必将引领新一轮的育种技术革命。

Cell, 14 September 2017

Engineering Quantitative Trait Variation for Crop Improvement by Genome Editing

Author

Daniel Rodríguez-Leal, Zachary H. Lemmon, Jarrett Man, Madelaine E. Bartlett, Zachary B. Lippman*

Cold Spring Harbor Laboratory, Cold Spring Harbor, USA

Summary

Major advances in crop yields are needed in the coming decades. However, plant breeding is currently limited by incremental improvements in quantitative traits that often rely on laborious selection of rare naturally occurring mutations in gene-regulatory regions. Here, we demonstrate that CRISPR/Cas9 genome editing of promoters generates diverse cis-regulatory alleles that provide beneficial quantitative variation for breeding. We devised a simple genetic scheme, which exploits trans-generational heritability of Cas9 activity in heterozygous loss-of-function mutant backgrounds, to rapidly evaluate the phenotypic impact of numerous promoter variants for genes regulating three major productivity traits in tomato: fruit size, inflorescence branching, and plant architecture. Our approach allows immediate selection and fixation of novel alleles in transgene-free plants and fine manipulation of yield components. Beyond a platform to enhance variation for diverse agricultural traits, our findings provide a foundation for dissecting complex relationships between gene-regulatory changes and control of quantitative traits.