Maintenance and Function of the Barley Root Apical Meristem

根尖分生组织（RAM）中的干细胞生态位（stem cell niche， SCN）为植物整个根系的建立和维持提供了必要的干细胞池。到目前为止，大多数关于RAMs的研究都是在拟南芥模式植物中进行的。本研究表明，除了植物激素生长素和细胞分裂素外，一些关键转录因子（TFs）如WUSCHEL RELATED HOMEOBOX 5、over1 -4和SHORTROOT and SCARECROW在RAM维持中发挥重要作用。在复杂的相互作用中，这些tf调节静止的中心定位和分裂，这对功能性SCN和功能性RAM至关重要。在像大麦这样的单子叶谷物中，对控制从干细胞命运到分化的必要的严格但也灵活的调控的分子因素知之甚少。初步实验表明，在大麦RAM的SCN中观察到的更大的干细胞池产生额外的细胞层，这是一个更复杂的分子调控。此外，一些预测的同源分子调控因子不表达或在不同细胞中表达，表明大麦RAM与拟南芥相比具有不同的功能。为了了解谷物RAM是如何组织、维持及其功能的，我们的目标是i)识别迄今为止未知的调节大麦RAM的分子因子作为谷物模型，此外，ii)仔细检查来自拟南芥的已知分子因子的同源物，以了解它们在大麦RAM维持中的功能相关性。

The stem cell niche (SCN) in the root apical meristem (RAM) provides the pool of stem cells necessary for the establishment and maintenance of the whole root system of a plant. Until now, most of the research on RAMs has been carried out in the eudicot model plant Arabidopsis thaliana. Here, it was shown that in addition to the phytohormones auxin and cytokinin, some of the key transcription factors (TFs) e.g., WUSCHEL RELATED HOMEOBOX 5, PLETHORA 1-4 and SHORTROOT and SCARECROW play important roles in RAM maintenance. In an intricate interplay these TFs regulate quiescent center positioning and divisions, which is crucial to a functional SCN and therefore also for a functional RAM. In monocot cereals like barley very little is known about the molecular factors controlling the necessary tight but also flexible regulation from stem cell fate to differentiation. Primary experiments suggest a more elaborate molecular regulation of the observed bigger stem cell pool in the SCN of the barley RAM generating also additional cell layers. Moreover, some predicted homologous molecular regulators are not expressed or in different cells indicating different functions in the barley RAM compared to Arabidopsis. To understand how the RAM of cereals is organized, maintained and how it functions, we aim to i) identify until now unknown molecular factors regulating the barley RAM as a cereal model and, in addition, ii) scrutinize the homologs of known molecular factors from Arabidopsis for their functional relevance in barley RAM maintenance.