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的时间来开发优良的近交亲本系，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由需要多年来产生这些近交亲本系的事实引起的。 该项目的目的是开发一种捷径，使近交亲本系在一年内产生。 为了实现这一目标，研究人员计划使用基因编辑技术来产生新的洋葱植物，从而大大加快自交系发育的过程。 在这项工作中部署的战略也应该广泛适用于其他作物，使其普遍使用的植物育种界。这项工作将与沃里克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CENH 3基因，以产生单倍体诱导系。单倍体诱导系是指通过异花授粉产生的种子的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“即时近交”系。 威斯康星州大学的研究小组将使用T-DNA转化和粒子轰击方法将基因编辑试剂输送到洋葱体细胞胚中，而沃里克大学的研究小组将使用烟草拨浪鼓病毒（TRV）表达载体。 并行部署各种基因编辑策略应该使研究人员能够快速确定哪种方法对于有效地产生修饰的CENH 3等位基因最有效。 为了使双单倍体技术在商业上可用于杂交种子生产，生产双单倍体的策略必须与细胞质雄性不育育种系统相容。因此，该项目将把单倍体诱导系的生产整合到细胞质雄性不育育种框架中，以最大限度地提高育种者的实际效益和适用性。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值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.