The role of cytokinin and CKX genes in regulating seed yield in barley and oilseed rape

由于世界人口的快速增长，稳定或提高农业植物的产量非常重要。作物产量的调控是一个复杂的过程，涉及许多基因，其中大多数是未知的。CKX基因已被证明在单子叶和双子叶植物的产量控制中发挥作用。这些基因编码蛋白质，这些蛋白质催化植物激素细胞分裂素的分解。本研究旨在探讨CKX基因在大麦中的作用。和油菜(Brassica napus L.)更详细地说。该项目的第一部分建议研究两个基因HvCKX2.1和HvCKX2.2在大麦产量形成中的作用，这两个基因与众所周知的水稻产量基因OsCKX2相关。这里，重点是通过基因组编辑产生的相应的Hvckx2.1和Hvckx2.2单突变体和双突变体的分子和表型特征。将在温室和田间分析突变体的生殖发育和产量形成，重点是穗和种子的发育。第二种被研究的作物是油菜，这是欧洲最重要的油料作物。申请人的研究小组发现了两个CKX基因，它们在控制库容量方面发挥着关键作用，库容量对高产非常重要。BnCKX3和BnCKX5的同时失活导致更高的细胞分裂素含量，从而激活花序分生组织和其他生殖组织。这导致形成更多的花，更多的豆荚和更多的胚珠，最终获得更高的种子产量。在拟议的项目中，将调查一个特定的Bnck x3，5油菜籽突变体种子含油量高的原因。此外，还分析了6个BnCKX3和BnCKX5等位基因对温室和大田产量形成的贡献。额外的产量基因的作用，特别是增加来源的形成，在油菜中进行了检验，在拟南芥中进行了比较。最后，从大麦和油菜的野生系、陆地系和育种系的基因组数据中探索了驯化过程中CKX基因的选择。

Due to the rapidly growing world population, stabilizing or increasing the yields of agricultural plants is of great importance. Regulation of crop yield is a complex process involving numerous genes, most of which are unknown. CKX genes have been shown to play a role in yield control in monocots and dicots. These genes code for proteins, which catalyze the breakdown of the plant hormone cytokinin. It is the aim of this proposal to investigate the role of certain CKX genes in barley (Hordeum vulgare L.) and oilseed rape (Brassica napus L.) in more detail. The first part of the project proposes to investigate the role of two genes, HvCKX2.1 and HvCKX2.2, which are related to the well-known yield gene OsCKX2 of rice, in yield formation in barley. Here, the focus is on the molecular and phenotypic characterization of corresponding Hvckx2.1 and Hvckx2.2 single and double mutants generated by genome editing. Mutant reproductive development and yield formation will be analyzed in the greenhouse and in the field, with a focus on spike and seed development. The second crop studied is oilseed rape, the most important oil crop in Europe. The applicant's research group has discovered two CKX genes that play a key role in controlling sink strength, which is important for high yields. The simultaneous inactivation of BnCKX3 and BnCKX5 leads to a higher cytokinin content and thereby to an activation of the inflorescence meristem and other reproductive tissues. This results in the formation of more flowers, more pods with more ovules, and ultimately a higher seed yield. In the proposed project, the reasons for a high oil content in the seeds of a specific Bnckx3,5 rapeseed mutant are to be investigated. Furthermore, the contribution of each of the six BnCKX3 and BnCKX5 alleles to yield formation in the greenhouse and in the field is analyzed. The effect of additional yield genes, which in particular increase source formation, is examined in oilseed rape and comparatively in Arabidopsis. Last but not least, the selection of CKX genes during domestication is explored in genomic data from wild, land and breeding lines of barley and oilseed rape.