背景回顾：In cell–cell communication, noncell-autonomous transcription factors play vital roles in controlling plant stem cell fate.  

前期基础：We previously reported that AUXIN RESPONSE FACTOR3 (ARF3), a member of the ARF family with critical roles in floral meristem maintenance and determinacy, has a distinct accumulation pattern that differs from the expression domain of its encoding gene in the shoot apical meristem (SAM). 

提出问题：However, the biological meaning of this difference is obscure. 

结果1-ARF3的细胞自主性作用：Here, we demonstrate that ARF3 expression in Arabidopsis (Arabidopsis thaliana) is mainly activated at the periphery of the SAM by auxin where ARF3 cell autonomously regulates the expression of meristem–organ boundary-specific genes, such as CUP-SHAPED COTYLEDON1-3 (CUC1-3), BLADE ON PETIOLE1-2 (BOP1-2), and TARGETS UNDER ETTIN CONTROL3 (TEC3) to regulate the arrangement of organs in regular pattern, a phenomenon referred to as phyllotaxis. 

结果2-ARF3的非细胞自主性作用：We also show that ARF3 is translocated into the organizing center where it represses cytokinin activity and WUSCHEL expression to regulate meristem activity noncell-autonomously. 

结论：Therefore, ARF3 acts as a molecular link that mediates the interaction of auxin and cytokinin signaling in the SAM while coordinating the balance between meristem maintenance and organogenesis. Our findings reveal an ARF3-mediated coordination mechanism through cell–cell communication in dynamic SAM maintenance. 

 摘 要 

在细胞间通讯过程中，非细胞自主性转录因子在控制植物干细胞命运中发挥至关重要的作用。作者先前的研究揭示了一个在花分生组织维持和有限性方面发挥重要作用的ARF基因家族的成员ARF3，该蛋白与其编码基因在茎尖分生组织（SAM）中的表达域具有完全不同的模式。但是，该现象的生物学意义还不清楚。本文中，作者发现拟南芥中ARF3基因在SAM周边的表达主要受到生长素的激活，而ARF3则会以细胞自主性的方式调控分生组织与器官边界特异基因CUC1-3、BOP1-2及TEC3的表达，从而确保器官以正常的模式排列，该现象即成为叶序。作者还发现，ARF3能够被转运至组织中心，在这里ARF3会抑制细胞分裂素的活性和WUS基因的表达，从而以非细胞自主性的方式调控分生组织活性。因此，ARF3作为一个分子桥梁，连接了SAM中生长素与细胞分裂素信号转导间的互作，协调分生组织维持和器官形成之间的平衡。本文的发现揭示了ARF3通过细胞间通讯介导的协调机制，从而作用于SAM的动态维持。

 刘西岗