背景回顾：Having a sense of direction is a fundamental cellular trait that can determine cell shape, division orientation, or function, and ultimately the formation of a functional, multicellular body. 

细胞极性：Cells acquire and integrate directional information by establishing discrete subcellular domains along an axis with distinct molecular profiles, a process known as cell polarization. 

提出问题：Insight into the principles and mechanisms underlying cell polarity has been propelled by decades of extensive research mostly in yeast and animal models. Our understanding of cell polarity establishment in plants, which lack most of the regulatory molecules identified in other eukaryotes, is more limited, but significant progress has been made in recent years.

主要内容-1：In this review, we explore how plant cells coordinately establish stable polarity axes aligned with the organ axes, highlighting similarities in the molecular logic used to polarize both plant and animal cells. 

主要内容-2：We propose a classification system for plant cell polarity events and nomenclature guidelines. 

主要内容-3：Finally, we provide a deep phylogenetic analysis of polar proteins and discuss the evolution of polarity machineries in plants.

 摘 要 

具有方向感是一种基本的细胞特征，其可以决定细胞的形状、分裂方向或功能，并最终决定一个功能性多细胞生物体的形成。细胞沿着不同分子特征的体轴，通过建立离散的亚细胞区域，来获取和整合方向信息，这一过程称为细胞极化。数十年的广泛研究推动了我们对于细胞极性基本原理和机制的深入了解，而相关的知识主要是来自于酵母和动物模型。植物缺乏其它真核生物中所鉴定的大多数调节分子，我们对于植物细胞极性建立的理解比较有限，但近年来相关领域取得了重大进展。本文中，作者探讨了植物细胞如何协调建立与器官轴对应的稳定极性轴，并突出了植物和动物中用于极化的分子逻辑的相似性。另外，作者还提出了一套用于植物细胞极性事件的分类系统和命名指南。最后，作者对极性蛋白进行了深入的系统发育分析，并讨论了植物极性机制的演化。