Maintenance and Function of Barley Shoot Meristems

植物茎分生组织的建立、维持和终止在拟南芥等优生植物中得到了广泛的研究，并阐明了在不同的生长期调节这些复杂干细胞生态位活动的基因调控网络。草的结构及其复杂的花序非常独特，并依赖于多样化的分生组织，其调节和功能尚未阐明。先前在玉米和水稻上的研究表明，一些控制拟南芥分生组织发育的关键信号通路和转录因子网络在禾本科植物中只有部分保守。尽管谷物干细胞系统对于更基本的植物干细胞系统的概念理解具有巨大的重要性，但谷物干细胞系统仍然是一个未被开发的领域。我们已经开始研究大麦分生组织和干细胞的调控，以我们对拟南芥信号通路的了解为起点。我们发现，CLAVATA类信号通路也在大麦中发挥作用，并控制大麦花序中不同分生组织的增殖。我们使用定向突变策略来产生作用于干细胞调节的多个受体激酶的突变，并开始研究它们的表达模式。我们的初步数据表明，在不同的大麦分生组织中，保守的多肽激活受体激酶信号通路控制着生长和分化，但它们的调节、表达模式及其在植物发育中的整合是非常不同的，并且是禾本科植物所特有的。我们建议通过诱导突变和表达研究来探索CLE多肽和CLAVATA-家族受体信号在大麦干细胞系统中的功能，并为不同的地上分生组织类型产生单细胞RNA测序信息，以确定它们的特征基因表达谱。通过将我们的结果与我们的财团合作伙伴在大麦、玉米和担子草干细胞调控方面密切相关的工作结合起来，我们将共同加深对谷类植物干细胞系统的理解。

Establishment, maintenance and termination of plant shoot meristems has been extensively studied in eudicots such as Arabidopsis, and gene regulatory networks that adjust the activities of these complex stem cell niches during changing growth periods have been elucidated. The architecture of grass and their complex inflorescences is very distinct, and relies upon diversified meristems whose regulation and functions have not yet been elucidated. Studies in maize and rice previously showed that some of the key signalling pathways and transcription factor networks which were found to control Arabidopsis meristem development are only partially conserved in grasses. Despite their enormous importance for a more fundamental conceptual understanding of plant stem cell systems, cereal stem cell systems still represent an underexplored territory. We have started to investigate barley meristem and stem cell regulation using our knowledge on Arabidopsis signalling pathways as a starting point. We found that a CLAVATA-like signalling pathway operates also in barley, and controls the proliferation of different meristems in the barley inflorescence. We used a targeted mutagenesis strategy to generate mutants for multiple receptor kinases that act in stem cell regulation, and started to study their expression patterns. Our preliminary data indicate that conserved peptide activated receptor kinase signalling pathways control growth and differentiation in the diverse barley meristems, but that their regulation, expression patterns and their integration into plant development is very distinct and specialised for grasses. We propose here to explore the functions of CLE peptide and CLAVATA-family receptor signalling in barley stem cell systems using induced mutations and expression studies, and generate single cell RNA sequencing information for the different above-ground meristem types to identify their characteristic gene expression profiles. By integrating our results with those of our consortium partners that are working on closely related aspects of stem cell regulation in barley, maize and Brachypodium, we will jointly develop a deeper understanding of stem cell systems of cereal plants.