Role of the plasmodesmata localized ACR4 and CLV1 receptor kinases in controlling stem cell fate in the root

根干细胞域的稳态是通过静止中心（QC）、干细胞和周围进入分化的细胞之间的信号传导来实现的。目前尚不清楚细胞如何相互沟通以微调增殖和分化之间的平衡。最近的研究表明，控制远端根分生组织干细胞数量的膜相关受体激酶 ACR4 和 CLV1 在胞连丝位点相互作用，表明 ACR4-CLV1 复合物可能调节根分生组织稳态所需的信号分子的运动。在这个项目中，我们计划分析 ACR4-CLV1 复合物是否以及如何控制分生组织细胞之间的连接，以及这种调节如何有助于维持根​​稳态。此外，我们将在感知 CLE40 肽后阐明 ACR4-CLV1 复合物的下游靶标。因此，我们将对 QC 进行转录谱分析，并与分选的小柱干细胞进行比较，无论是否经过 CLE40 肽处理。此外，我们将采用遗传筛选来识别调节增殖和分化之间平衡的新成分。随后的基因克隆和功能分析将扩大我们对 ACR4-CLV1 信号通路的理解。该项目中获得的结果将有助于该领域了解时空通讯如何整合根分生组织中的干细胞行为。因此，该研究项目将解决生物学中的一个基本问题：如何产生和维持具有不同身份的细胞的短程模式，以及如何通过局部信号控制细胞增殖和分化，并与整个生物体的生长需求相结合。此外，了解植物茎生态位的寿命将使研究人员能够改善植物的总体生长和生物量生产。

The homeostasis of the root stem cell domain is achieved by signaling between the quiescent centre (QC), stem cells and the surrounding cells that enter differentiation. It is not yet understood how cells communicate with each other in order to fine tune the balance between proliferation and differentiation. Recent work showed that the membrane associated receptor kinases ACR4 and CLV1, which control stem cell number in the distal root meristem, interact at the sites of plasmodesmata, suggesting that ACR4-CLV1 complexes may regulate the movement of signaling molecules necessary for root meristem homeostasis. In this project we plan to analyze if, and how, ACR4-CLV1 complexes control connectivity between meristem cells, and how this regulation contributes to the maintenance of root homeostasis. Furthermore, we will elucidate the downstream targets of ACR4-CLV1 complexes after perception of the CLE40 peptide. Therefore, we will perform transcript profiling of the QC in comparison with sorted columella stem cells, with or without CLE40 peptide treatment. Additionally, we will employ a genetic screen to identify new components regulating the balance between proliferation and differentiation. Ensuing gene cloning and functional analysis will expand our understanding of the ACR4-CLV1 signalling pathway. The results obtained in the proposed project will help the field in understanding how spatiotemporal communication integrates stem cell behaviour in the root meristem. Thus, this research project will address a fundamental problem in biology: how short range patterns of cells with different identities are generated and maintained, and how cell proliferation and differentiation is controlled by local signaling and is integrated with the growth requirements of the entire organism. Furthermore, understanding the longevity of plant stem niches will allow researchers to improve in general plant growth and biomass production.