Maintenance and Function of Barley Shoot Meristems

植物茎分生组织的建立、维持和终止已经在真双子叶植物如拟南芥中被广泛研究，并且已经阐明了在变化的生长期期间调节这些复杂干细胞小生境的活性的基因调控网络。草及其复杂花序的结构非常独特，并且依赖于多样化的分生组织，其调节和功能尚未阐明。先前在玉米和水稻中的研究表明，一些被发现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仅部分保守。尽管其巨大的重要性，更基本的概念理解植物干细胞系统，谷物干细胞系统仍然是一个未充分探索的领域。我们已经开始调查大麦分生组织和干细胞的调控，利用我们的知识拟南芥信号通路作为起点。我们发现CLAVATA样信号通路也在大麦中起作用，并控制大麦花序中不同分生组织的增殖。我们使用靶向诱变策略来产生在干细胞调节中起作用的多个受体激酶的突变体，并开始研究它们的表达模式。我们的初步数据表明，保守的肽激活受体激酶信号通路控制不同的大麦分生组织的生长和分化，但它们的调节，表达模式和整合到植物发育是非常独特的，专门为草。我们建议在这里探索CLE肽和CLAVATA家族受体信号转导在大麦干细胞系统中的功能，使用诱导突变和表达研究，并产生单细胞RNA测序信息的不同地上分生组织类型，以确定其特征基因表达谱。通过将我们的研究结果与我们的合作伙伴的研究成果相结合，这些合作伙伴正在研究大麦，玉米和短柄草中干细胞调控的密切相关方面，我们将共同对谷类植物的干细胞系统有更深入的了解。

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.