Geng Yuan, Xie Chong, Zhang Cankui, Liu Xing, Zhou Yun
Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA.
Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA.
Plant Cell Environ. 2025 Mar;48(3):2125-2131. doi: 10.1111/pce.15286. Epub 2024 Nov 18.
A fascinating feature of land plants is their ability to continually initiate new tissues and organs throughout their lifespan, driven by a pool of pluripotent stem cells located in meristems. In seed plants, various types of meristems are initiated and maintained during the sporophyte generation, while their gametophytes lack meristems and rely on sporophyte tissues for growth. In contrast, seed-free vascular plants, such as ferns, develop meristems during both the sporophyte and gametophyte generations, allowing for the independent growth of both generations. Recent findings have highlighted both conserved and lineage-specific roles of the HAIRY MERISTEM (HAM) family of GRAS-domain transcriptional regulators in various meristems throughout the land plant lifecycle. Here, we review and discuss how HAM genes maintain meristem indeterminacy in both sporophytes and gametophytes, with a focus on studies performed in two model species: the flowering plant Arabidopsis thaliana and the fern Ceratopteris richardii. Additionally, we summarize the crucial and tightly regulated functions of the microRNA171 (miR171)-HAM regulatory modules, which define HAM spatial patterns and activities during meristem development across various meristem identities in land plants.
陆生植物一个引人入胜的特征是，在其整个生命周期中，它们能够由位于分生组织中的多能干细胞库驱动，不断产生新的组织和器官。在种子植物中，各种类型的分生组织在孢子体世代中起始并维持，而它们的配子体缺乏分生组织，依靠孢子体组织生长。相比之下，无籽维管植物，如蕨类植物，在孢子体和配子体世代均发育分生组织，使得两个世代都能独立生长。最近的研究结果突出了GRAS结构域转录调节因子的毛状分生组织（HAM）家族在陆生植物整个生命周期的各种分生组织中既保守又具有谱系特异性的作用。在这里，我们回顾并讨论HAM基因如何在孢子体和配子体中维持分生组织的不确定性，重点关注在两种模式植物中进行的研究：开花植物拟南芥和蕨类植物里氏鸟巢蕨。此外，我们总结了微小RNA171（miR171）-HAM调控模块的关键且受到严格调控的功能，这些功能在陆生植物中跨各种分生组织身份定义了HAM在分生组织发育过程中的空间模式和活性。
