BTT EAGER: A system for the production of haploid inducer lines and cytoplasmic male sterile doubled haploids for efficient hybrid production

杂交品种是现代作物生产的基石。种子公司花了很多年开发精英自交系亲本，用于生产农民每个季节种植的杂交种子。植物育种周期中的一个主要瓶颈是需要多年才能培育出这些近亲系的事实。这个项目的目的是开发一种捷径，允许在一年内产生自交系亲本。为了实现这一目标，研究人员计划使用基因编辑技术来培育新的洋葱植株，从而极大地加快近交系的发展进程。这项工作中部署的策略也应该广泛适用于其他作物，使其对植物育种界具有普遍用途。这项工作将与华威大学的斯蒂芬·杰克逊博士合作进行。研究人员将使用CRISPR/Cas9方法将遗传变异引入洋葱的CENH3基因，以获得单倍体诱导系。单倍体诱导系是一种通过异花授粉产生的种子中有很大一部分是单倍体的植物。在化学诱导的染色体加倍后，这些单倍体后代成为可以立即用于杂交种子生产的“即刻自交系”。威斯康星大学的研究小组将使用T-DNA转化和基因轰击的方法将基因编辑试剂导入洋葱体细胞胚胎，而华威大学的研究小组将使用烟草骚动病毒(TRV)表达载体。同时部署各种基因编辑策略应该可以让研究人员快速确定哪种方法最有效地产生修饰的CENH3等位基因。为了使加倍单倍体技术在商业上用于杂交制种，产生加倍单倍体的策略必须与细胞质雄性不育育种系统兼容。因此，该项目将在细胞质雄性不育育种框架内整合单倍体诱导系的生产，以最大限度地提高实际效益和对育种者的适用性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Hybrid cultivars are a cornerstone of modern crop production. Seed companies spend many years developing elite, inbred parental lines that are used to produce the hybrid seed that farmers plant each season. A major bottleneck in the plant breeding cycle is caused by the fact that it takes many years to produce these inbred parental lines. The aim of this project is to develop a shortcut that allows inbred parental lines to be produced in a single year. To accomplish this goal, the investigators plan to use gene editing techniques to generate novel onion plants that greatly accelerate the process of inbred line development. The strategy deployed in this work should also be broadly applicable to other crops, making it of general use to the plant breeding community. This work will be carried out in collaboration with Dr. Stephen Jackson at the University of Warwick.The investigators will use CRISPR/Cas9 methods to introduce genetic variation into the CENH3 gene of onion in order to produce haploid-inducer lines. A haploid-inducer line is a plant from which a significant fraction of the seed produced by cross-pollination is haploid. Upon chemically-induced chromosome doubling, these haploid progeny become "instant inbred" lines that can be immediately used for hybrid seed production. The research team at the University of Wisconsin will use T-DNA transformation and particle bombardment methods to deliver the gene editing reagents into onion somatic embryos, while the group at the University of Warwick will use tobacco rattle virus (TRV) expression vectors. Deploying a variety of gene-editing strategies in parallel should allow the investigators to quickly determine which approach is the most effective for efficiently producing modified CENH3 alleles. In order for doubled haploid technology to be commercially useful for hybrid seed production, it is essential that the strategies for producing doubled haploids are compatible with cytoplasmic male sterile breeding systems. For this reason, this project will integrate the production of haploid inducer lines within a cytoplasmic male sterile breeding framework in order to maximize the practical benefit and applicability to breeders.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.