转录因子FAM调控拟南芥茎端和根端分生组织形成和维持的分子机理研究

植物的分生组织是植物器官发生和形态建成的主要细胞来源。尽管对于分生组织发育的机理有了一定的认识，但调控茎端和根端干细胞分化和维持的上游关键因子还知之甚少。我们筛选到一个拟南芥功能未知的bHLH转录因子的突变体，其茎端分生组织比野生型明显变大，STM、WUS、CLV3等干细胞关键调控基因表达显著上调，暗示该转录因子作用于它们的上游，将其命名为FAT SHOOT MERISTEM（FAM）。FAM在茎端和根端分生组织中均特异表达。除茎端表型外，fam突变体根端干细胞的分化也出现异常。说明FAM是调控茎端和根端分生组织发育的关键因子。本项目拟进一步研究FAM调控茎端和根端分生组织干细胞分化和维持的生物学功能；分析FAM与已知干细胞关键调控因子的关系；鉴定FAM调控的靶基因，进而建立FAM调控顶端分生组织干细胞功能的分子遗传网络。研究结果将为理解植物顶端分生组织形成和维持的机理提供新的重要信息。

Plant architecture is mainly determined by the developmental regulation of shoot or root apical meristems. Although the molecular mechanism underlying meristem development has been studied, the functions of the essential upstream regulators of stem cell specification remain to be further explored. We have identified a basic helix–loop–helix (bHLH) transcription factor named FAM. fam mutants show larger size of shoot meristem and more rosette leaves than those in the wild-type plants. Interestingly, the roots of fam show the reduced numbers and disordered arrangement of columella cells. These results suggest that FAM functions as a conserved regulator in both shoot and root meristem maintenance. Here, we will analyze the molecular functions of FAM in the regulation of stem cell specification and maintenance, reveal physical and genetic interactions between FAM and other identified essential stem cell regulators, and dissect the targets and downstream transcriptional pathway of FAM in regulating stem cell function. Our results will provide new information for the framework in meristem development of plant.